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Sample records for effective mechanical property

  1. Effects of irradiation on mechanical properties

    International Nuclear Information System (INIS)

    Server, W.L.; Griesbach, T.J.; Dragunov, Y.; Amaev, A.

    1998-01-01

    As a result of the popularity of the Agencies report 'Neutron Irradiation Embrittlement of Reactor Pressure Vessel Steels' of 1975, it was decided that another report on this broad subject would be of use. In this report, background and contemporary views on specially identified areas of the subject are considered as self-contained chapters, written by experts. The effects of irradiation on the mechanical properties of reactor pressure vessel steels are explained. This chapter provides some background on the critical elements controlling neutron damage effects. Distinction is made between vessels made in the USA and in the former USSR

  2. effects of sulphur addition on addition on and mechanical properties

    African Journals Online (AJOL)

    User

    234-8034714355. 8034714355. 1. EFFECTS OF SULPHUR ADDITION ON. ADDITION ON. 2. AND MECHANICAL PROPERTIES O. 3. 4. C. W. Onyia. 5. 1DEPT. OF METALLURGICAL AND MATERIALS. 6. 2, 4DEPT. OF METALLURGICAL ...

  3. The Effect of Bedding Structure on Mechanical Property of Coal

    Directory of Open Access Journals (Sweden)

    Zetian Zhang

    2014-01-01

    Full Text Available The mechanical property of coal, influencing mining activity considerably, is significantly determined by the natural fracture distributed within coal mass. In order to study the effecting mechanism of bedding structure on mechanical property of coal, a series of uniaxial compression tests and mesoscopic tests have been conducted. The experimental results show that the distribution characteristic of calcite particles, which significantly influences the growth of cracks and the macroscopic mechanical properties of coal, is obviously affected by the bedding structure. Specifically, the uniaxial compression strength of coal sample is mainly controlled by bedding structure, and the average peak stress of specimens with axes perpendicular to the bedding planes is 20.00 MPa, which is 2.88 times the average amount of parallel ones. The test results also show a close relationship between the bedding structure and the whole deformation process under uniaxial loading.

  4. The Effects of Moisture Content on Mechanical Properties of Soybean

    African Journals Online (AJOL)

    Some mechanical properties were determined for four varieties of soybean (TGX 297-129C, Samsoy1, TGX 306-636C and TGX 536-02D). The hardness, compressive and tensile strength determination were carried out using a Rockwell Hardness machine and tensometer. The effect of moisture content on the hardness ...

  5. Effect of surfactants on the mechanical properties of acetaminophen ...

    African Journals Online (AJOL)

    The purpose of this study was to investigate the effect of non ionic surfactant on the mechanical properties of acetaminophen-wax matrix tablet and hence its implication on dissolution profile. Acetaminophen-wax matrix granules were prepared by melt granulation technique. This was formed by triturating acetaminophen ...

  6. Size Effect of Defects on the Mechanical Properties of Graphene

    Science.gov (United States)

    Park, Youngho; Hyun, Sangil

    2018-03-01

    Graphene, a two-dimensional material, has been studied and utilized for its excellent material properties. In reality, achieving a pure single-crystalline structure in graphene is difficult, so usually graphene may have various types of defects in it. Vacancies, Stone-Wales defects, and grain boundaries can drastically change the material properties of graphene. Graphene with vacancy defects has been of interest because it is a two-dimensional analogy of three-dimensional porous materials. It has efficient material properties, and can function as a part of modern devices. The mechanical properties have been studied by using molecular dynamics for either a single vacancy defect with various sizes or multiple vacancy defects with same defect ratios. However, it is not clear which one has more influence on the mechanical properties between the size of the defects and the defect ratio. Therefore, we investigated the hole-size effect on the mechanical properties of single-crystalline graphene at various defect ratios. A void defect with large size can have a rather high tensile modulus with a low fracture strain compared to a void defect with small size. We numerically found that the tensile properties of scattered single vacancies is similar to that of amorphous graphene. We suspect that this is due to the local orbital change of the carbon atoms near the boundary of the void defects, so-called the interfacial phase.

  7. Effect of Mechanical Alloying Atmospheres and Oxygen Concentration on Mechanical Properties of ODS Ferritic Steels

    International Nuclear Information System (INIS)

    Noh, Sanghoon; Choi, Byoungkwon; Han, Changhee; Kim, Kibaik; Kang, Sukhoon; Chun, Youngbum; Kim, Taekyu

    2013-01-01

    Finely dispersed nano-oxide particles with a high number density in the homogeneous grain matrix are essential to achieve superior mechanical properties at high temperatures, and these unique microstructures can be obtained through the mechanical alloying (MA) and hot consolidation process. The microstructure and mechanical property of ODS steel significantly depends on its powder property and the purity after the MA process. These contents should be carefully controlled to improve the mechanical property at elevated temperature. In particular, appropriate the control of oxygen concentration improves the mechanical property of ODS steel at high temperature. An effective method is to control the mechanical alloying atmosphere by high purity inert gas. In the present study, the effects of mechanical alloying atmospheres and oxygen concentration on the mechanical property of ODS steel were investigated. ODS ferritic alloys were fabricated in various atmospheres, and the HIP process was used to investigate the effects of MA atmospheres and oxygen concentration on the microstructure and mechanical property. ODS ferritic alloys milled in an Ar-H 2 mixture, and He is effective to reduce the excess oxygen concentration. The YH 2 addition made an extremely reduced oxygen concentration by the internal oxygen reduction reaction and resulted in a homogeneous microstructure and superior creep strength

  8. Effects of humidity on the mechanical properties of gecko setae.

    Science.gov (United States)

    Prowse, Michael S; Wilkinson, Matt; Puthoff, Jonathan B; Mayer, George; Autumn, Kellar

    2011-02-01

    We tested the hypothesis that an increase in relative humidity (RH) causes changes in the mechanical properties of the keratin of adhesive gecko foot hairs (setae). We measured the effect of RH on the tensile deformation properties, fracture, and dynamic mechanical response of single isolated tokay gecko setae and strips of the smooth lamellar epidermal layer. The mechanical properties of gecko setae were strongly affected by RH. The complex elastic modulus (measured at 5 Hz) of a single seta at 80% RH was 1.2 GPa, only 39% of the value when dry. An increase in RH reduced the stiffness and increased the strain to failure. The loss tangent increased significantly with humidity, suggesting that water absorption produces a transition to a more viscous type of deformation. The influence of RH on the properties of the smooth epidermal layer was comparable with that of isolated seta, with the exception of stress at rupture. These values were two to four times greater for the setae than for the smooth layer. The changes in mechanical properties of setal keratin were consistent with previously reported increases in contact forces, supporting the hypothesis that an increase in RH softens setal keratin, which increases adhesion and friction. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  9. Effects of pore design on mechanical properties of nanoporous silicon

    International Nuclear Information System (INIS)

    Winter, Nicholas; Becton, Matthew; Zhang, Liuyang; Wang, Xianqiao

    2017-01-01

    Nanoporous silicon has been emerging as a powerful building block for next-generation sensors, catalysts, transistors, and tissue scaffolds. The capability to design novel devices with desired mechanical properties is paramount to their reliability and serviceability. In order to bring further resolution to the highly variable mechanical characteristics of nanoporous silicon, here we perform molecular dynamics simulations to study the effects of ligament thickness, relative density, and pore geometry/orientation on the mechanical properties of nanoporous silicon, thereby determining its Young's modulus, ultimate strength, and toughness as well as the scaling laws versus the features of interior ligaments. Results show that pore shape and pattern dictate stress accumulation inside the designed structure, leading to the corresponding failure signature, such as stretching-dominated, bending-dominated, or stochastic failure signatures, in nanoporous silicon. The nanostructure of the material is also seen to drive or mute size effects such as “smaller is stronger” and “smaller is ductile”. This investigation provides useful insight into the behavior of nanoporous silicon and how one might leverage its promising applications. - Graphical abstract: Molecular dynamics simulations are performed to study the effects of ligament thickness, relative density, and pore geometry/orientation on the mechanical properties of nanoporous silicon, thereby determining its Young's modulus, ultimate strength, and toughness as well as the scaling trends versus the features of interior ligaments.

  10. Modeling the mechanics of cancer: effect of changes in cellular and extra-cellular mechanical properties.

    Science.gov (United States)

    Katira, Parag; Bonnecaze, Roger T; Zaman, Muhammad H

    2013-01-01

    Malignant transformation, though primarily driven by genetic mutations in cells, is also accompanied by specific changes in cellular and extra-cellular mechanical properties such as stiffness and adhesivity. As the transformed cells grow into tumors, they interact with their surroundings via physical contacts and the application of forces. These forces can lead to changes in the mechanical regulation of cell fate based on the mechanical properties of the cells and their surrounding environment. A comprehensive understanding of cancer progression requires the study of how specific changes in mechanical properties influences collective cell behavior during tumor growth and metastasis. Here we review some key results from computational models describing the effect of changes in cellular and extra-cellular mechanical properties and identify mechanistic pathways for cancer progression that can be targeted for the prediction, treatment, and prevention of cancer.

  11. Effect of smelt aluminium on mechanical properties of steels

    International Nuclear Information System (INIS)

    Ryabov, V.R.; Dykhno, I.S.; Deev, G.F.; Karikh, V.V.

    1987-01-01

    Effect of smelt aluminium on mechanical properties of armco-iron and 12 Kh18N10T steel is studied. It is stated that in smelt aluminium and aluminium alloy contact with armco-iron the sample ductility is decreased. Corrosion effect of smelt alluminium on (18Kh15N5AM3) steel in the form of reinforced wire in aluminium-steel KAS-1A composite material is investigted. It is stated in experiment that during smelt alluminium-steel contact interaction of heterogeneous phases takes place

  12. Surface effects on the mechanical properties of nanoporous materials

    International Nuclear Information System (INIS)

    Lu Zixing; Zhang Cungang; Liu Qiang; Yang Zhenyu

    2011-01-01

    In this paper, surface effects on the mechanical behaviour of nanoporous materials are investigated using the theory of surface elasticity and Timoshenko beam theory based on the tetrakaidecahedron (or Kelvin) open-cell foam model. Meanwhile, the influence of surface elasticity and residual surface stress on the mechanical properties of nanoporous materials is discussed. In addition, the results derived from the theory of Euler-Bernoulli beam model are also provided for comparison. Theoretical results show that the effective Young's modulus of the nanoporous materials increases as the diameter of the strut decreases, but in contrast Poisson's ratio and the brittle collapse strength decrease with the diameter of the strut. The contribution of shear deformation to surface effects on elastic properties is more significant, while the surface effects on brittle collapse strength are not sensitive to shear deformation, and it can even be neglected. As the strut size increases, the present results can be reduced to the cases without considering surface effects, which verifies the efficiency of the present model to a certain extent.

  13. Gamma radiation effect study in polycarbonate optical and mechanics properties

    International Nuclear Information System (INIS)

    Araujo, E.S. de.

    1991-02-01

    Polycarbonates (PC) are used in different industrial applications due to their excellent dielectric characteristics, impact resistance, and high temperature resistance. In some of these applications, the polycarbonates are exposed to gamma radiation which produces molecular scissions, causing changes in the polycarbonate properties. To estimate the radiation effects in the Durolon polycarbonate, samples were irradiated with 60 Co gamma rays with doses between 0,2 kGy and 300 kGy. The results obtained showed that the PC mechanical properties are not changed due to the gamma radiation. However the results showed an expressive variation in the yellowness index for doses above 1 kGy. The results showed that it is possible to use the gamma sterilization of PC in applications where the coloration of PC is not critical. (author). 21 refs, 25 figs, 3 tabs

  14. Effect of vacancies on the mechanical properties of phosphorene nanotubes

    Science.gov (United States)

    Sorkin, V.; Zhang, Y. W.

    2018-06-01

    Using density functional tight-binding method, we studied the mechanical properties, deformation and failure of armchair (AC) and zigzag (ZZ) phosphorene nanotubes (PNTs) with monovacancies and divacancies subjected to uniaxial tensile strain. We found that divacancies in AC PNTs and monovacancies in ZZ PNTs possess the lowest vacancy formation energy, which decreases with the tube diameter in AC PNTs and increases in ZZ PNTs. The Young’s modulus is reduced, while the radial and thickness Poisson’s ratios are increased by hosted vacancies. In defective AC PNTs, deformation involves fracture of the intra-pucker bonds and formation of the new inter-pucker bonds at a critical strain, and the most stretched bonds around the vacancy rupture first, triggering a sequence of the structural transformations terminated by the ultimate failure. The critical strain of AC PNTs is reduced significantly by hosted vacancies, whereas their effect on the critical stress is relatively weaker. Defective ZZ PNTs fail in a brittle-like manner once the most stretched bonds around a vacancy rupture, and vacancies are able to significantly reduce the failure strain but only moderately reduce the failure stress of ZZ PNTs. The understandings revealed here on the mechanical properties and the deformation and failure mechanisms of PNTs provide useful guidelines for their design and fabrication as building blocks in nanodevices.

  15. Surface effects on the mechanical properties of nanoporous materials

    International Nuclear Information System (INIS)

    Xia Re; Li Xide; Feng Xiqiao; Qin Qinghua; Liu Jianlin

    2011-01-01

    Using the theory of surface elasticity, we investigate the mechanical properties of nanoporous materials. The classical theory of porous materials is modified to account for surface effects, which become increasingly important as the characteristic sizes of microstructures shrink to nanometers. First, a refined Timoshenko beam model is presented to predict the effective elastic modulus of nanoporous materials. Then the surface effects on the elastic microstructural buckling behavior of nanoporous materials are examined. In particular, nanoporous gold is taken as an example to illustrate the application of the proposed model. The results reveal that both the elastic modulus and the critical buckling behavior of nanoporous materials exhibit a distinct dependence on the characteristic sizes of microstructures, e.g. the average ligament width.

  16. Surface effects on the mechanical properties of nanoporous materials

    Energy Technology Data Exchange (ETDEWEB)

    Xia Re [School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072 (China); Li Xide; Feng Xiqiao [AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084 (China); Qin Qinghua [School of Engineering, Australian National University, Canberra, ACT 0200 (Australia); Liu Jianlin, E-mail: fengxq@tsinghua.edu.cn [Department of Engineering Mechanics, China University of Petroleum, Qingdao 266555 (China)

    2011-07-01

    Using the theory of surface elasticity, we investigate the mechanical properties of nanoporous materials. The classical theory of porous materials is modified to account for surface effects, which become increasingly important as the characteristic sizes of microstructures shrink to nanometers. First, a refined Timoshenko beam model is presented to predict the effective elastic modulus of nanoporous materials. Then the surface effects on the elastic microstructural buckling behavior of nanoporous materials are examined. In particular, nanoporous gold is taken as an example to illustrate the application of the proposed model. The results reveal that both the elastic modulus and the critical buckling behavior of nanoporous materials exhibit a distinct dependence on the characteristic sizes of microstructures, e.g. the average ligament width.

  17. Effect of the mechanical processing on the mechanical properties of MA956 alloy. II. Mechanical characterization

    International Nuclear Information System (INIS)

    Chao, J.; Gonzalez-Doncel, G.

    1998-01-01

    The mechanical properties at room and low temperature of MA 956 alloy in some stages of their processing route are evaluated. In this study the influence of crystallographic orientation on plastic deformation and brittle fracture, strongly anisotropic phenomena, is also considered. It is concluded that even though MA 956 alloy was designated for high temperature applications it could be also used for cryogenic temperatures applications. (Author) 8 refs

  18. Effect of mechanical properties on erosion resistance of ductile materials

    Science.gov (United States)

    Levin, Boris Feliksovih

    incorporating this parameter into a new erosion model, good correlation was observed with experimentally measured erosion rates. An increase in area under the microhardness curve led to an increase in erosion resistance. It was shown that an increase in hardness below the eroded surface occurs mainly due to the strain-rate hardening effect. Strain-rate sensitivities of tested materials were estimated from the nanoindentation tests and showed a decrease with an increase in materials hardness. Also, materials combining high hardness and strain-rate sensitivity may offer good erosion resistance. A methodology is presented to determine the proper mechanical properties to incorporate into the erosion parameter based on the physical model of the erosion mechanism in ductile materials.

  19. Effect of polybutenes on mechanical and physical properties of polypropylene

    International Nuclear Information System (INIS)

    Nascimento, Uedson A. do; Timoteo, Gustavo Arante V.; Rabello, Marcelo S.

    2009-01-01

    This study investigated the effect of polybutene (PIB) of molecular weights ranging from 480 the 1.600 g/mol in polypropylene homopolymer. Compositions with 0, 3, 5 and 7% of PIB were prepared in internal mixer and compression moulded. The properties evaluated were: tensile strength, scanning electron microscopy (SEM), FTIR, X-ray diffraction (XRD) and melt flow index (IF). The results of mechanical tests showed that the presence of the plasticizer reduced the tensile strength, elastic modulus and hardness. The analysis of XRD showed a drop in the degree of crystallinity of PP/PIB blends. The micrographs obtained by SEM did not reveal the occurrence of the phase separation. The IF analysis confirm the effect of PIB as internal lubricant's, by increasing the rate of flow. (author)

  20. Effects of moisture on the mechanical properties of glass fibre ...

    Indian Academy of Sciences (India)

    However, the properties were relatively inferior when treated with boiling water for longer hours attributing to ingress of moisture by capillary action through the interface between the fibre and the resin matrix. Considering the rates of moisture absorption and correlating with the mechanical properties, it was observed that the ...

  1. Effects of Polyethylene Glycol on the Mechanical Properties of ...

    African Journals Online (AJOL)

    Akorede

    investigate the mechanical properties and microstructural evaluation of steel. The test ... quenchant on the properties of steel (Eshraghi-Kakhki et al, ... Alloy Steel ... Table 1: Chemical composition of the steel used in this experiment. Elements. C. Si. S ... Cu. W. As. Composition 0.0555 0.00180 0.0029 0.3031 0.0003 0.0060.

  2. Topological effects on the mechanical properties of polymer knots

    Science.gov (United States)

    Zhao, Yani; Ferrari, Franco

    2017-11-01

    The mechanical properties of knotted polymer rings under stretching in a bad or good solvent are investigated by applying a force F to a point of the knot while keeping another point fixed. The Monte Carlo sampling of the polymer conformations is performed on a simple cubic lattice using the Wang-Landau algorithm. The specific energy, specific heat capacity, gyration radius and the force-elongation curves are computed for several knot topologies with lengths up to 120 lattice units. The common features of the mechanical and thermal behavior of stretched short polymer rings forming knots of a given topological type are analyzed as well as the differences arising due to topology and size effects. It is found that these systems admit three different phases depending on the values of the tensile force F and the temperature T. The transitions from one phase to the other are well characterized by the peaks of the specific heat capacity and by the data of the gyration radius and specific energy. At very low temperatures the force-elongation curves show that the stretching of a knot is a stepwise process, which becomes smooth at higher temperatures. Criteria for distinguishing topological and size effects are provided. It turns out from our study that the behavior of short polymer rings is strongly influenced by topological effects. In particular, the swelling and the swelling rate of knots are severely limited by the topological constraints. Several other properties that are affected by topology, like the decay of the specific energy at high tensile forces, are discussed. The fading out of the influences of topological origin with increasing knot lengths has been verified. Some anomalies detected in the plots of the specific heat capacity of very short and complex knots have been explained by the limitations in the number of accessible energy states due to the topological constraints.

  3. Effect of Precuring Warming on Mechanical Properties of Restorative Composites

    Directory of Open Access Journals (Sweden)

    Kareem Nada

    2011-01-01

    Full Text Available To investigate the effect of prepolymerization warming on composites' mechanical properties, three composites were evaluated: Clearfil Majesty (CM (Kuraray, Z-100 (3M/ESPE, and Light-Core (LC (Bisco. Specimens were prepared from each composite at room temperature as control and 2 higher temperatures (37∘C and 54∘C to test surface hardness (SH, compressive strength (CS, and diametral tensile strength (DTS. Data were statistically analyzed using ANOVA and Fisher's LSD tests. Results revealed that prewarming CM and Z100 specimens significantly improved their SH mean values (P<0.05. Prewarming also improved mean CS values of Z100 specimens (P<0.05. Furthermore, DTS mean value of CM prepared at 52∘ was significantly higher than that of room temperature specimens (P<0.05. KHN, CS, and DTS mean values varied significantly among the three composites. In conclusion, Prewarming significantly enhanced surface hardness of 2 composites. Prewarming also improved bulk properties of the composites; however, this improvement was significant in only some of the tested materials.

  4. Effect of neutron irradiation on mechanical properties of ferritic steels

    International Nuclear Information System (INIS)

    Kass, S.B.; Murty, K.L.

    1995-01-01

    Effect of neutron radiation exposure was investigated in various ferritic steels with the main emphasis being the effects of thermal neutrons on radiation hardening. Pure iron of varied grain sizes was also used for characterizing the grain size effects on the source hardening before and after neutron irradiation. While many steels are considered in the overall study, the results on 1020, A516 and A588 steels are emphasized. Radiation hardening due to fast neutrons was seen to be sensitive to the composition of the steels with A354 being the least resistant and A490 the least sensitive. Majority of the radiation hardening stems from friction hardening, and source hardening term decreased with exposure to neutron radiation apparently due to the interaction of interstitial impurities with radiation produced defects. Inclusion of thermal neutrons along with fast resulted in further decrease in the source hardening with a slight increase in the friction hardening which revealed a critical grain size below which exposure to total (fast and thermal) neutron spectrum resulted in a slight reduction in the yield stress compared to the exposure to only fast neutrons. This is the first time such a grain size effect is reported and this is shown to be consistent with known radiation effects on friction and source hardening terms along with the observation that low energy neutrons have a nonnegligible effect on the mechanical properties of steels. In ferritic steels, however, despite their small grain size, exposure to total neutron spectrum yielded higher strengths than exposure to only fast neutrons. This behavior is consistent with the fact that the source hardening is small in these alloys and radiation effect is due only to friction stress

  5. Effects of moisture on the mechanical properties of glass fibre ...

    Indian Academy of Sciences (India)

    Unknown

    of moisture absorption and correlating with the mechanical properties, it was observed that the ..... where F is the flux of moisture molecules crossing a unit ... 300. 400. 500. 600. 700 wt% of nascent fibre loading. 63.50. 55.75. 48.48. 38.63.

  6. Effect of carbon nanofibre addition on the mechanical properties of ...

    Indian Academy of Sciences (India)

    Owing to the good mechanical properties of the carbon nanofibres (CNFs), they ... 8H Satin, T-300 carbon fabric (C-fabric) was used as rein- forcement. ... below. Absolute strength (S) in MPa at a given Vf: S = a + bVf + cV 2 f , where 'a' is the ...

  7. Bone Quality: The Mechanical Effects of Microarchitecture and Matrix Properties

    NARCIS (Netherlands)

    J.S. Day (Judd)

    2005-01-01

    textabstractIn this body of work we have examined some of the current concepts pertaining to the relation between bone mass, bone quality and the mechanical properties of bone. In our first series of studies we used a model of human osteoarthritis to investigate the implications of changes in the

  8. effects of sulphur addition on addition on and mechanical properties

    African Journals Online (AJOL)

    User

    on the microstructure and mechanical properties of sand cast been investigated ... owed that the addition of sulphur to Al-12wt%Si alloy. 12wt%Si alloy .... 28 materials. 29. Element. Aluminum. Silicon. Al. Si. Ca. Fe. Cu. Zn. Mn. Mg. Cr. B. 99.71.

  9. Effects of Basalt Fibres on Mechanical Properties of Concrete

    Directory of Open Access Journals (Sweden)

    El-Gelani A. M.

    2018-01-01

    Full Text Available This paper presents the results of an experimental program carried out to investigate the effects of Basalt Fibre Reinforced Polymers (BFRP on some fundamental mechanical properties of concrete. Basalt fibres are formed by heating crushed basalt rocks and funnelling the molten basalt through a spinneret to form basalt filaments. This type of fibres have not been widely used till recently. Two commercially available chopped basalt fibres products with different aspect ratios were investigated, which are dry basalt (GeoTech Fibre and basalt pre-soaked in an epoxy resin (GeoTech Matrix .The experimental work included compression tests on 96 cylinders made of multiple batches of concrete with varying amounts of basalt fibre additives of the two mentioned types, along with control batches containing no fibres. Furthermore, flexural tests on 24 prisms were carries out to measure the modulus of rupture, in addition to 30 prisms for average residual strength test. Results of the research indicated that use of basalt fibres has insignificant effects on compressive strength of plain concrete, where the increase in strength did not exceed about 5%. On the other hand, results suggest that the use of basalt fibres may increase the compressive strength of concrete containing fly as up top 40%. The rupture strength was increased also by 8% to 28% depending on mix and fibre types and contents. Finally, there was no clear correlation between the average residual strength and ratios of basalt fibres mixed with the different concrete batches.

  10. Effect of fibre content and alkali treatment on mechanical properties ...

    Indian Academy of Sciences (India)

    Administrator

    Department of Mechanical Engineering, National Institute of Technology, Warangal 506 004, India .... America, Florida, Texas and California. ... effectively transfer the stress to fibres. Also ... The present work investigated the effect of fibre con-.

  11. Effect of cold drawing on mechanical properties of biodegradable fibers.

    Science.gov (United States)

    La Mantia, Francesco Paolo; Ceraulo, Manuela; Mistretta, Maria Chiara; Morreale, Marco

    2017-01-26

    Biodegradable polymers are currently gaining importance in several fields, because they allow mitigation of the impact on the environment related to disposal of traditional, nonbiodegradable polymers, as well as reducing the utilization of oil-based sources (when they also come from renewable resources). Fibers made of biodegradable polymers are of particular interest, though, it is not easy to obtain polymer fibers with suitable mechanical properties and to tailor these to the specific application. The main ways to tailor the mechanical properties of a given biodegradable polymer fiber are based on crystallinity and orientation control. However, crystallinity can only marginally be modified during processing, while orientation can be controlled, either during hot drawing or cold stretching. In this paper, a systematic investigation of the influence of cold stretching on the mechanical and thermomechanical properties of fibers prepared from different biodegradable polymer systems was carried out. Rheological and thermal characterization helped in interpreting the orientation mechanisms, also on the basis of the molecular structure of the polymer systems. It was found that cold drawing strongly improved the elastic modulus, tensile strength and thermomechanical resistance of the fibers, in comparison with hot-spun fibers. The elastic modulus showed higher increment rates in the biodegradable systems upon increasing the draw ratio.

  12. The effect of thermo-mechanical processing on the mechanical properties of molybdenum - 2 volume % lanthana

    International Nuclear Information System (INIS)

    Mueller, A.J.; Shields, J.A. Jr.; Buckman, R.W. Jr.

    2001-01-01

    Variations in oxide species and consolidation method have been shown to have a significant effect on the mechanical properties of oxide dispersion strengthened (ODS) molybdenum material. The mechanical behavior of molybdenum - 2 volume % La 2 O 3 mill product forms, produced by CSM Industries by a wet doping process, were characterized over the temperature range of -150 o C to 1800 o C. The various mill product forms evaluated ranged from thin sheet stock to bar stock. Tensile properties of the material in the various product forms were not significantly affected by the vast difference in total cold work. Creep properties, however, were sensitive to the total amount of cold work as well as the starting microstructure. Stress-relieved .material had superior creep rupture properties to recrystallized material at 1200 o C, while at 1500 o C and above the opposite was observed. Thus it is necessary to match the appropriate thermo-mechanical processing and microstructure of molybdenum - 2 volume % La 2 O 3 to the demands of the application being considered. (author)

  13. Effects of water infusions on mechanical properties of carboniferous rocks

    Energy Technology Data Exchange (ETDEWEB)

    Vavro, M; Chlebik, J

    1977-01-01

    Method of water infusion is used in the Ostrava-Karvina coal region in Czechoslovakia, where the roof of the extracted coal seam consists of thick rock layers (sandstone, Namurian B series) characterized by high resistance to compression, high coefficient of linear elasticity and high capacity of accumulating energy. When the resistance boundary is crossed and the rocks are disturbed this energy is suddenly released and transferred to the surrounding rock masses, coal seam and support system. On the basis of laboratory experiments the physico-mechanical and energy properties of carboniferous rocks together with calculation of their energy coefficient and other parameters are described and calculated. The results of research and theoretical solutions are presented. Practical use of water infusions to influence mechanical properties of sandstone in the roof of coal seams is described with the example of the Dukla coal mine. (5 refs.) (In Polish)

  14. Effect of precipitates on mechanical properties of AA2195

    International Nuclear Information System (INIS)

    Kim, Jae-Hee; Jeun, Jeong-Hoon; Chun, Hyun-Jin; Lee, Ye Rim; Yoo, Joon-Tae; Yoon, Jong-Hoon; Lee, Ho-Sung

    2016-01-01

    Addition of 1–4 wt.% lithium into a conventional Al–Cu–Mg alloy allows lower density and higher mechanical properties, which are attractive for aerospace applications. In this study, fundamental investigations including phase and microstructure evolution, resulting in strengthening, of the AA2195 are conducted to observe a possibility of production with commercial level. Precipitation sequence and kinetics during post-annealing were evaluated with variations of temperature and holding time. Microstructures revealed formation and evolution in representative precipitates including θ (Al_2Cu), ß′ (Al_3Zr), and T (Al_xLi_yCu) series. Aluminum alloys have low hardness, modulus, and strength before aging, but precipitates such as θ′ (Al_2Cu), ß′ (Al_3Zr), and T_1 (Al_2LiCu) show enhanced mechanical properties of AA2195 tempered because of their interaction with dislocation. However, longer holding time and higher annealing temperature result in significant decreases in mechanical properties due to the presence of incoherent precipitates (θ phase) and coarsening of the precipitates via grain-boundary diffusion. In the current study, the tensile strength of 560 MPa was obtained with post-heat treatment without work hardening. This value has never been achieved in other studies. The maximum strength was reported as 500 MPa without a work hardening process. - Highlights: • A relationship between microstructure and mechanical properties to post annealing AA2195. • A formation and dissolution of the precipitates were observed for various treatment. • An optimum post-annealing condition was obtained.

  15. Effect of precipitates on mechanical properties of AA2195

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae-Hee [Launcher Structure and Materials Team, Korea Aerospace Research Institute, Daejeon (Korea, Republic of); Jeun, Jeong-Hoon [Department of Materials Science and Engineering, Seoul National University, Seoul (Korea, Republic of); Chun, Hyun-Jin [Southeast University, Nanjing (China); Lee, Ye Rim [Department of Aerospace System Engineering, University of Science & Technology, Daejeon (Korea, Republic of); Yoo, Joon-Tae [Launcher Structure and Materials Team, Korea Aerospace Research Institute, Daejeon (Korea, Republic of); Yoon, Jong-Hoon [Launcher Structure and Materials Team, Korea Aerospace Research Institute, Daejeon (Korea, Republic of); Department of Aerospace System Engineering, University of Science & Technology, Daejeon (Korea, Republic of); Lee, Ho-Sung, E-mail: hslee@kari.re.kr [Launcher Structure and Materials Team, Korea Aerospace Research Institute, Daejeon (Korea, Republic of); Department of Aerospace System Engineering, University of Science & Technology, Daejeon (Korea, Republic of)

    2016-06-05

    Addition of 1–4 wt.% lithium into a conventional Al–Cu–Mg alloy allows lower density and higher mechanical properties, which are attractive for aerospace applications. In this study, fundamental investigations including phase and microstructure evolution, resulting in strengthening, of the AA2195 are conducted to observe a possibility of production with commercial level. Precipitation sequence and kinetics during post-annealing were evaluated with variations of temperature and holding time. Microstructures revealed formation and evolution in representative precipitates including θ (Al{sub 2}Cu), ß′ (Al{sub 3}Zr), and T (Al{sub x}Li{sub y}Cu) series. Aluminum alloys have low hardness, modulus, and strength before aging, but precipitates such as θ′ (Al{sub 2}Cu), ß′ (Al{sub 3}Zr), and T{sub 1} (Al{sub 2}LiCu) show enhanced mechanical properties of AA2195 tempered because of their interaction with dislocation. However, longer holding time and higher annealing temperature result in significant decreases in mechanical properties due to the presence of incoherent precipitates (θ phase) and coarsening of the precipitates via grain-boundary diffusion. In the current study, the tensile strength of 560 MPa was obtained with post-heat treatment without work hardening. This value has never been achieved in other studies. The maximum strength was reported as 500 MPa without a work hardening process. - Highlights: • A relationship between microstructure and mechanical properties to post annealing AA2195. • A formation and dissolution of the precipitates were observed for various treatment. • An optimum post-annealing condition was obtained.

  16. Effects of Zoledronate and Mechanical Loading during Simulated Weightlessness on Bone Structure and Mechanical Properties

    Science.gov (United States)

    Scott, R. T.; Nalavadi, M. O.; Shirazi-Fard, Y.; Castillo, A. B.; Alwood, J. S.

    2016-01-01

    Space flight modulates bone remodeling to favor bone resorption. Current countermeasures include an anti-resorptive drug class, bisphosphonates (BP), and high-force loading regimens. Does the combination of anti-resorptives and high-force exercise during weightlessness have negative effects on the mechanical and structural properties of bone? In this study, we implemented an integrated model to mimic mechanical strain of exercise via cyclical loading (CL) in mice treated with the BP Zoledronate (ZOL) combined with hindlimb unloading (HU). Our working hypothesis is that CL combined with ZOL in the HU model induces additive structural and mechanical changes. Thirty-two C57BL6 mice (male,16 weeks old, n8group) were exposed to 3 weeks of either HU or normal ambulation (NA). Cohorts of mice received one subcutaneous injection of ZOL (45gkg), or saline vehicle, prior to experiment. The right tibia was axially loaded in vivo, 60xday to 9N in compression, repeated 3xweek during HU. During the application of compression, secant stiffness (SEC), a linear estimate of slope of the force displacement curve from rest (0.5N) to max load (9.0N), was calculated for each cycle once per week. Ex vivo CT was conducted on all subjects. For ex vivo mechanical properties, non-CL left femurs underwent 3-point bending. In the proximal tibial metaphysis, HU decreased, CL increased, and ZOL increased the cancellous bone volume to total volume ratio by -26, +21, and +33, respectively. Similar trends held for trabecular thickness and number. Ex vivo left femur mechanical properties revealed HU decreased stiffness (-37),and ZOL mitigated the HU stiffness losses (+78). Data on the ex vivo Ultimate Force followed similar trends. After 3 weeks, HU decreased in vivo SEC (-16). The combination of CL+HU appeared additive in bone structure and mechanical properties. However, when HU + CL + ZOL were combined, ZOL had no additional effect (p0.05) on in vivo SEC. Structural data followed this trend with

  17. Effect of diluted alloying elements on mechanical properties of iron

    International Nuclear Information System (INIS)

    Hassan, A.A.S.

    1996-01-01

    Iron and its alloys have extensive applications. The effect of solute additions on mechanical properties of iron was investigated to check the efficiency of solute atoms on strength and surface e life. Additions in the range of 0.1 wt.% and 0.3 wt.% of alloying elements of Cu,Ni and Si were used. Samples of grains size ranged from 6-40 m which have been prepared by annealing followed by furnace cooling. The recrystallization temperature increases with alloying addition (475 degree C for Fe-0.3 wt. % C alloy compared to 375 degree C for pure iron). Si and Cu additions inhibit grain growth of iron whereas Ni addition enhances it.Addition of Si or Ni to iron induced softening below room temperature whereas addition of Cu caused hardening. The work hardening parameters decreased due to alloying additions. The strength coefficient K was 290 M N/m2 for Fe-03 wt % Ni compared to 340 M N/m2 for pure iron. The work hardening exponent n is 0.12 for fe-0.3 wt. Cu alloy compared to 0.17 for pure iron. All the investigated alloys fulfilled the Hall-Petch relation at liquid Nitrogen and at room temperature. Alloying addition which caused softening addition which caused hardening increased the Half-Petch parameters. Ni addition favors ductility of iron whereas Cu addition reduces it. Alloying additions generally lead to brittle fracture and decrease the crack resistance of iron. 9 tabs., 55 figs., 103 refs

  18. Effective thermo-mechanical properties and shape memory effect of CNT/SMP composites

    Science.gov (United States)

    Yang, Qingsheng; Liu, Xia; Leng, Fangfang

    2009-07-01

    Shape memory polymer (SMP) has been applied in many fields as intelligent sensors and actuators. In order to improve the mechanical properties and recovery force of SMP, the addition of minor amounts of carbon nanotubes (CNT) into SMP has attracted wide attention. A micromechanical model and thermo-mechanical properties of CNT/SMP composites were studied in this paper. The thermo-mechanical constitutive relation of intellectual composites with isotropic and transversely isotropic CNT was obtained. Moreover, the shape memory effect of CNT/SMP composites and the effect of temperature and the volume fraction of CNT were discussed. The work shows that CNT/SMP composites exhibit excellent macroscopic thermo-mechanical properties and shape memory effect, while both of them can be affected remarkably by temperature and the microstructure parameters.

  19. Effects of gamma rays on the physical and mechanical properties of hide

    International Nuclear Information System (INIS)

    Sutrisno Puspodikoro.

    1976-01-01

    The effect of gamma rays on the physical and mechanical properties of hide has been studied, using Gammacell 220 as an irradiator. The determination of the physical and mechanical properties of the irradiated hide was carried out by Balai Penelitian Kulit (Leather Research Institute) at Yogyakarta. Experiments show that up to a certain dose of irradiation, favourable effects can be obtained, while higher doses impair the physical and mechanical properties of the leather raw materials. (author)

  20. Effect of extrusion processing on the microstructure, mechanical properties, biocorrosion properties and antibacterial properties of Ti-Cu sintered alloys

    International Nuclear Information System (INIS)

    Zhang, Erlin; Li, Shengyi; Ren, Jing; Zhang, Lan; Han, Yong

    2016-01-01

    Ti-Cu sintered alloys, Ti-Cu(S) alloy, have exhibited good anticorrosion resistance and strong antibacterial properties, but low ductility in previous study. In this paper, Ti-Cu(S) alloys were subjected to extrusion processing in order to improve the comprehensive property. The phase constitute, microstructure, mechanical property, biocorrosion property and antibacterial activity of the extruded alloys, Ti-Cu(E), were investigated in comparison with Ti-Cu(S) by X-ray diffraction (XRD), optical microscopy (OM), scanning electronic microscopy (SEM) with energy disperse spectroscopy (EDS), mechanical testing, electrochemical testing and plate-count method in order to reveal the effect of the extrusion process. XRD, OM and SEM results showed that the extrusion process did not change the phase constitute but refined the grain size and Ti 2 Cu particle significantly. Ti-Cu(E) alloys exhibited higher hardness and compressive yield strength than Ti-Cu(S) alloys due to the fine grain and Ti 2 Cu particles. With the consideration of the total compressive strain, it was suggested that the extrusion process could improve the ductility of Ti-Cu alloy(S) alloys. Electrochemical results have indicated that the extrusion process improved the corrosion resistance of Ti-Cu(S) alloys. Plate-count method displayed that both Ti-Cu(S) and Ti-Cu(E) exhibited strong antibacterial activity (> 99%) against S. aureus. All these results demonstrated that hot forming processing, such as the extrusion in this study, refined the microstructure and densified the alloy, in turn improved the ductility and strength as well as anticorrosion properties without reduction in antibacterial properties. - Highlights: • Hot extrusion refined the grain size and Ti 2 Cu phase significantly. • Hot extrusion increased the mechanical properties and the corrosion resistance. • The antibacterial properties was not affected by the hot process.

  1. Chemical Modification Effect on the Mechanical Properties of Coir Fiber

    Directory of Open Access Journals (Sweden)

    Samia Sultana Mir

    2012-04-01

    Full Text Available Natural fiber has a vital role as a reinforcing agent due to its renewable, low cost, biodegradable, less abrasive and eco-friendly nature. Whereas synthetic fibers like glass, boron, carbon, metallic, ceramic and inorganic fibers are expensive and not eco-friendly. Coir is one of the natural fibers easily available in Bangladesh and cheap. It is derived from the husk of the coconut (Cocos nucifera. Coir has one of the highest concentrations of lignin, which makes it stronger. In recent years, wide range of research has been carried out on fiber reinforced polymer composites [4-13].The aim of the present research is to characterize brown single coir fiber for manufacturing polymer composites reinforced with characterized fibers. Adhesion between the fiber and polymer is one of factors affecting the strength of manufactured composites. In order to increase the adhesion, the coir fiber was chemically treated separately in single stage (with Cr2(SO43•12(H2O and double stages (with CrSO4 and NaHCO3. Both the raw and treated fibers were characterized by tensile testing, Fourier transform infrared (FTIR spectroscopic analysis, scanning electron microscopic analysis. The result showed that the Young’s modulus increased, while tensile strength and strain to failure decreased with increase in span length. Tensile properties of chemically treated coir fiber was found higher than raw coir fiber, while the double stage treated coir fiber had better mechanical properties compared to the single stage treated coir fiber. Scanning electron micrographs showed rougher surface in case of the raw coir fiber. The surface was found clean and smooth in case of the treated coir fiber. Thus the performance of coir fiber composites in industrial application can be improved by chemical treatment.

  2. Irradiation effects on the mechanical properties of composite organic insulators

    International Nuclear Information System (INIS)

    Egusa, S.; Kirk, M.A.; Birtcher, R.C.; Hagiwara, M.; Kawanishi, S.

    1983-01-01

    Four kinds of cloth-filled organic composites (filler: glass or carbon fiber; matrix: epoxy or polymide resin) were irradiated with 2-MeV electrons at room temperature, and were examined with regard to the mechanical properties. Following irradiation, the Young's (tensile) modulus of these composites remains practically unchanged even after irradiation up to 15,000 Mrad. The shear modulus and the ultimate strength, on the other hand, begin to decrease after the absorbed dose reaches about 2000 Mrad for the glass/epoxy composite and about 5000 approx. 10,000 Mrad for the other composites. This result is ascribed to the decrease in the capacity of load transfer from the matrix to the fiber due to the radiation-induced debonding at the interface. As to the fracture behavior, the propagation energy increases from the beginning of irradiation. This result is attributed to the radiation-induced decrease in the bonding energy at the interface. The same study was made also for these composites and an alumina fiber-epoxy composite irradiated with fast neutrons at room temperature and 5 0 K. 7 figures, 1 table

  3. Radiation Effects on Mechanical Properties of LDPE/EVA blend

    International Nuclear Information System (INIS)

    Lee, Chung; Kim, Ki Yup; Im, Don Sun; Ryu, Boo Hyung

    2005-01-01

    Restricted properties and a limited use of homopolymers alone, have given rise to an exploration of composites, copolymers, blends, etc. Copolymers such as poly(ethylene-co-vinyl acetate) (EVA), poly(ethylene-co-butyl acrylate), poly(ethylene-co-ethyl acrylate) (EEA) have wide usages in different industry. Among the numerous ethylene copolymers, due to its wide range of properties depending on its vinyl acetate content, EVA has become one of the most useful copolymers in the electrical industry as a cable insulator, and in many other industries as a hot melt adhesive, a coating, etc. Several works looked at the influence of gamma rays on polymers. Zhang et al have blended EVA with PE because crosslinked PE has a low flexibility for use as a cable insulation. It was reported that the blend showed have a better elongation, flexibility and heat aging effect than PE, but its hardness and softening point were lower. In this study, the radiation degradation of LDPE/EVA blends as a function of the vinyl acetate contents was investigated by using TGA, gelation and elongation

  4. Effect of addition of organo clay on mechanical properties and dynamic-mechanical based TPV

    International Nuclear Information System (INIS)

    Honorato, Luciana R.; Silva, Adriana A.; Soares, Bluma G.; Soares, Ketly P.

    2011-01-01

    The effect of organophilic clay on the mechanical and dynamical-mechanical properties of thermoplastic elastomers based on polypropylene (PP) and nitrile rubber (NBR) was investigated. The addition of clay was performed from a master batch prepared by a solution intercalation of NBR inside the clay galleries. Since the PP/NBR blend is highly incompatible, PP functionalized with maleic anhydride (PP-g-MA) and carboxylated NBR (XNBR) were employed as compatibilizing system together with triethylene-tetramine (TETA) used as coupling agent. The addition of Clay inside the elastomeric phase of the TPV resulted in a significant decrease of the elongation at break without changes on the tensile strength. The presence of clay also promoted a slight increase of the storage modulus and the glass transition temperature. The small angle X ray scattering confirmed the high dispersion of clay inside the TPV. Analysis of light scattering small angle (SAXS) confirmed the high dispersion of clay in the matrix of the TPV. (author)

  5. Study of effect of gamma radiation on molecular weight and mechanical properties of PHB and PHNV

    International Nuclear Information System (INIS)

    Fechine, Guilhermino J.M.; Terence, Mauro C.; Rabello, M.S.; Willen, Renate M.R.

    2011-01-01

    The effect of gamma radiation on molecular weight and mechanical properties (tensile and flexural) of PHB and PHBV samples was investigated. The values of stress and strain at the break point for both mechanical properties indicated that scission molecular reactions were predominant in PHB and PHBV samples submitted to gamma radiation. These results were confirmed by Size Exclusion Chromatography (SEC) analysis. (author)

  6. Effect of extrusion processing on the microstructure, mechanical properties, biocorrosion properties and antibacterial properties of Ti-Cu sintered alloys.

    Science.gov (United States)

    Zhang, Erlin; Li, Shengyi; Ren, Jing; Zhang, Lan; Han, Yong

    2016-12-01

    Ti-Cu sintered alloys, Ti-Cu(S) alloy, have exhibited good anticorrosion resistance and strong antibacterial properties, but low ductility in previous study. In this paper, Ti-Cu(S) alloys were subjected to extrusion processing in order to improve the comprehensive property. The phase constitute, microstructure, mechanical property, biocorrosion property and antibacterial activity of the extruded alloys, Ti-Cu(E), were investigated in comparison with Ti-Cu(S) by X-ray diffraction (XRD), optical microscopy (OM), scanning electronic microscopy (SEM) with energy disperse spectroscopy (EDS), mechanical testing, electrochemical testing and plate-count method in order to reveal the effect of the extrusion process. XRD, OM and SEM results showed that the extrusion process did not change the phase constitute but refined the grain size and Ti2Cu particle significantly. Ti-Cu(E) alloys exhibited higher hardness and compressive yield strength than Ti-Cu(S) alloys due to the fine grain and Ti2Cu particles. With the consideration of the total compressive strain, it was suggested that the extrusion process could improve the ductility of Ti-Cu alloy(S) alloys. Electrochemical results have indicated that the extrusion process improved the corrosion resistance of Ti-Cu(S) alloys. Plate-count method displayed that both Ti-Cu(S) and Ti-Cu(E) exhibited strong antibacterial activity (>99%) against S. aureus. All these results demonstrated that hot forming processing, such as the extrusion in this study, refined the microstructure and densified the alloy, in turn improved the ductility and strength as well as anticorrosion properties without reduction in antibacterial properties. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Effects of fibre orientation on mechanical properties of hybrid

    Indian Academy of Sciences (India)

    ... properties such as tensile, flexural, impact and hardness were investigated. ... in strength and also attracted several studies covering green technologies. ... Engineering, Noorul Islam Centre for Higher Education, Kumaracoil 629 180, India ...

  8. Effects of fibre content on mechanical properties and fracture ...

    Indian Academy of Sciences (India)

    Administrator

    cost. The most important factors that affect the short fibres reinforcement are ... made with conventional techniques, including single or twin screw extruding (Li et al 2005), wet ball-milling mixing (Song et al 2002) and high-speed mechanical.

  9. Effects of surface atomistic modification on mechanical properties of gold nanowires

    International Nuclear Information System (INIS)

    Sun, Xiao-Yu; Xu, Yuanjie; Wang, Gang-Feng; Gu, Yuantong; Feng, Xi-Qiao

    2015-01-01

    Highlights: • Molecular dynamics simulations of surface modification effect of Au nanowires. • Surface modification can greatly affect the mechanical properties of nanowires. • Core–shell model is used to elucidate the effect of residual surface stress. - Abstract: Modulation of the physical and mechanical properties of nanowires is a challenging issue for their technological applications. In this paper, we investigate the effects of surface modification on the mechanical properties of gold nanowires by performing molecular dynamics simulations. It is found that by modifying a small density of silver atoms to the surface of a gold nanowire, the residual surface stress state can be altered, rendering a great improvement of its plastic yield strength. This finding is in good agreement with experimental measurements. The underlying physical mechanisms are analyzed by a core–shell nanowire model. The results are helpful for the design and optimization of advanced nanomaterial with superior mechanical properties

  10. Dynamic mechanical analysis of compatibilizer effect on the mechanical properties of wood flour/high-density polyethylene composites

    Science.gov (United States)

    Mehdi Behzad; Medhi Tajvidi; Ghanbar Ehrahimi; Robert H. Falk

    2004-01-01

    In this study, effect of MAPE (maleic anhydride polyethylene) as the compatibilizer on the mechanical properties of wood-flour polyethylene composites has been investigated by using Dynamic Mechanical Analysis (DMA). Composites were made at 25% and 50% by weight fiber contents and 1% and 2% compatibilizer respectively. Controls were also made at the same fiber contents...

  11. Effects of radiation induced polymerisation on the mechanical properties of polymer impregnated concrete

    International Nuclear Information System (INIS)

    Ohgishi, S.; Ono, H.; Kasahara, Y.

    1980-01-01

    In this programme, effects of electron irradiation energy on mechanical properties of polymer impregnated concrete (PIC) were examined with regard to the density of the base cement mortar, the total exposure dose, the radiation source and other factors. (author)

  12. Mechanical properties of uniaxial natural fabric Grewia tilifolia reinforced epoxy based composites: Effects of chemical treatment

    CSIR Research Space (South Africa)

    Jayaramudu, J

    2014-07-01

    Full Text Available The effects of chemical treatment on the mechanical, morphological, and chemical resistance properties of uniaxial natural fabrics, Grewia tilifolia/epoxy composites, were studied. In order to enhance the interfacial bonding between the epoxy matrix...

  13. Effect of interfacial properties on mechanical stability of ash deposit

    Directory of Open Access Journals (Sweden)

    A. Ontiveros-Ortega

    2016-04-01

    Full Text Available The paper presents a study on the cohesion of volcanic ash particles using surface free energy determination and zeta potential analyses. This is a subject of great interest in physical volcanology, as many researches on volcanic particle aggregation are frequently reported. In this case, special attention is paid to the role of structural or hydration forces between hydrophilic surfaces, which are a consequence of the electron-donor/electron-acceptor character of the interface. From this point of view, the results are potentially interesting as they could give valuable insights into this process. The results are presented in terms of the total energy of interaction between dispersed particles, computed from the extended DLVO theory. Contributions to the total free energy of interaction were determined from the zeta potential and surface free energy of ash, measured under different experimental conditions. Two samples of basaltic volcanic ash (black and white with silica contents of 44% and 63% respectively are studied. The surface free energy and zeta potential were analysed for ashes immersed in different electrolytes (NaCl, CaCl2, FeCl3. The presence of electrolytes changes the surface properties of the solid materials. The analysis of total interaction energy between the ash particles in aqueous medium shows that soil cohesion strongly depends on ash surface properties, chemical nature, the adsorbed cation on the surface, and pH value.

  14. Glass fiber effect on mechanical properties of Eco-SCC

    Science.gov (United States)

    Prasad M. L., V.; Loksesh, G.; Ramanjaneyulu, B.; Venkatesh, S.; Mousumi, K.

    2017-07-01

    Sustainable Construction encouraging the use of recycled materials and implies adoption of fewer natural resources in buildings and other infrastructure. In this paper Quarry Dust (QD) is used as partial replacement for River Sand (RS) to make Self Compacting Concrete (SCC) of grade M40. Glass fiber is used as strengthening material to the developed concrete. The present study mainly focused to develop Eco-SCC using QD. In this study it was found that, for developing Eco-SCC, what is the optimum dosage of replacement of QD in RS. Fresh properties of SCC are satisfying the EFNARC specifications and also target strength is achieved. Further it is concluded that, with the glass fiber addition there is an improvement in the split and flexural strength values.

  15. Metal-ceramic materials. Study and prediction of effective mechanical properties

    International Nuclear Information System (INIS)

    Karakulov, Valerii V.; Smolin, Igor Yu.

    2016-01-01

    Mechanical behavior of stochastic metal-ceramic composite materials was numerically simulated on mesoscopic scale level. Deformation of mesoscopic volumes of composites, whose structure consists of a metal matrix and randomly distributed ceramic inclusions, was numerically simulated. The results of the numerical simulation were used for evaluation of the effective elastic and strength properties of metal-ceramic materials with different parameters of the structure. The values of the effective mechanical properties of investigated materials were obtained, and the character of the dependence of the effective elastic and strength properties on the structure parameters of composites was determined.

  16. Stress relief of austenitic weldments: microstructural and mechanical property effects

    International Nuclear Information System (INIS)

    Thomas, R.G.

    1982-01-01

    Two consumables suitable for welding AISI 316 have been studied. Both contained 3-8% delta-ferrite in the as-welded state but were of different nominal compositions, namely 19Cr-12Ni-3Mo and 17Cr-8Ni-2Mo. The results of a series of uniaxial stress relaxation tests carried out over a range of temperatures from 650 to 850 0 C indicate that it was practicable to achieve acceptable residual stress levels even at the lower end of this temperature range; the inference was, therefore, that the final choice of stress relief treatment will be determined by the metallurgical changes that simultaneously occur. The isothermal transformation kinetics of the delta-ferrite were determined over the temperature range 600-800 0 C for both weld metals and the nature and morphology of the phases formed was studied. Transformation proceeded more rapidly in the 19Cr-12Ni-3Mo deposit than in the 17Cr-8Ni-2Mo deposit. Electron microscopy revealed that in both weld metals the delta-ferrite acted as a focus for a series of complex precipitation reactions involving initially the simultaneous formation of M 23 C 6 and reversion of delta to #betta# followed by precipitation of intermetallic phases chi and σ. Tensile impact and creep properties of aged material have been determined and are discussed in terms of the structural features observed. (author)

  17. Effect of bias voltage on microstructure and mechanical properties of ...

    Indian Academy of Sciences (India)

    In the present study, authors report on the effect that substrate bias voltage has on the ... ings and at high deposition rates, having a wide range of .... The coatings were then ultra- ... The results of a typical compositional analysis carried out.

  18. Effect of potential factors in manufacturing process on mechanical properties of F82H

    Energy Technology Data Exchange (ETDEWEB)

    Sakasegawa, Hideo, E-mail: sakasegawa.hideo@jaea.go.jp [Japan Atomic Energy Agency, Rokkasho, Aomori 039-3212 (Japan); Tanigawa, Hiroyasu [Japan Atomic Energy Agency, Rokkasho, Aomori 039-3212 (Japan); Tanigawa, Hisashi; Hirose, Takanori [Japan Atomic Energy Agency, Naka, Ibaraki 311-0193 (Japan)

    2014-10-15

    Highlights: • Effects of hot forging and cooling method on mechanical properties were studied. • Differences, inhomogeneity, and anisotropy in tensile and Charpy impact properties were observed for plates with a lower hot forging level. • No significant difference was observed in tensile and Charpy impact properties between air cooled and water quenched samples. - Abstract: A DEMO reactor requires over 3500 tons of reduced activation ferritic/martensitic steel. To prepare such a large quantity of the material with appropriate mechanical properties, it is important to study the effect of various factors in the manufacturing process for mass production. In our work, we focused on the effects of hot forging and the cooling method after normalizing, which have not been previously studied. Plates with three different thicknesses were fabricated from slabs with two different hot forging reduction ratios, and the tensile and Charpy impact properties were evaluated for each of these plates. The plates made using a lower hot forging reduction ratio had different tensile properties, and inhomogeneity and anisotropy were observed in the Charpy impact test results. These results indicate that the hot forging operation to which the ingot is initially subjected must be sufficiently high to ensure that the appropriate mechanical properties are achieved. To test the effect of the cooling method, plates cooled in air and those quenched in water after normalizing were prepared, and tensile and Charpy impact tests were performed on these plates. No significant differences were observed indicating that air cooling is sufficient to obtain the appropriate mechanical properties.

  19. Effect of temperature on the mechanical properties of polymer mortars

    Directory of Open Access Journals (Sweden)

    João Marciano Laredo dos Reis

    2012-08-01

    Full Text Available This paper presents the results of an experimental program to investigate the effect of temperature on the performance of epoxy and unsaturated polyester polymer mortars (PM. PM is a composite material in which polymeric materials are used to bond the aggregates in a fashion similar to that used in the preparation of Portland cement concrete. For this purpose, prismatic and cylindrical specimens were prepared for flexural and compressive tests, respectively, at different temperatures. Measurements of the temperature-dependent elastic modulus and the compressive and flexural strength were conducted using a thermostatic chamber attached to a universal test machine for a range of temperatures varying from room temperature to 90 ºC. The flexural and compressive strength decreases as temperature increases, especially after matrix HDT. Epoxy polymer mortars are more sensitive to temperature variation than unsaturated polyester ones.

  20. Helium effect on mechanical property of fusion reactor structural materials

    International Nuclear Information System (INIS)

    Yamamoto, Norikazu; Chuto, Toshinori; Murase, Yoshiharu; Nakagawa, Johsei

    2004-01-01

    High-energy neutrons produced in fusion reactor core caused helium in the structural materials of fusion reactors, such as blankets. We injected alpha particles accelerated by the cyclotron to the samples of martensite steel (9Cr3WVTaB). Equivalent helium doses injected to the sample is estimated to be up to 300 ppm, which were estimated to be equivalent to helium accumulation after the 1-year reactor operation. Creep tests of the samples were made to investigate helium embrittlement. There were no appreciable changes in the relation between the stresses and the rupture time, the minimum creep rate and the applied stress. Grain boundary effect by helium was not observed in ruptured surfaces. Fatigue tests were made for SUS304 samples, which contain helium up to 150 ppm. After 0.05 Hz cyclic stress tests, it was shown that the fatigue lifetime (cycles to rupture and extension to failure) are 1/5 in 150 ppm helium samples compared with no helium samples. The experimental results suggest martensite steel is promising for structural materials of fusion reactors. (Y. Tanaka)

  1. Effects of Yb on the mechanical properties and microstructures of an Al-Mg alloy

    International Nuclear Information System (INIS)

    Song Min; Wu Zhenggang; He Yuehui

    2008-01-01

    This paper reported a first study of the effects of Yb on the microstructures and mechanical properties of an extruded Al-Mg alloy. It has been shown that the addition of 0.3 wt.% Yb decreases the mechanical properties of the alloy since Mg- and Yb-containing constituents decrease the concentration of Mg solute atoms in Al matrix, and thus the solution strengthening effect. However, the addition of 1 wt.% Yb substantially improves the mechanical behavior of the alloy because the concentration of Yb solute atoms in Al matrix is high enough to generate solution strengthening effect. The improvement in the mechanical properties is due to the large work-hardening and high dislocation density caused by the interaction between dislocations and Yb and Mg solute atoms. The Yb and Mg atoms inhibit the dynamic recovery and recrystallization of the alloy, thus provide a uniformly distributed dislocation structure with high density

  2. Effect of processing conditions on the mechanical and thermal properties of high-impact polypropylene nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Furlan, L G [Federal Institute of Rio Grande do Sul, IFRS, Campus Restinga, Estrada Joao Antonio da Silveira, 351, Porto Alegre 91790-400 (Brazil); Ferreira, C I; Dal Castel, C; Santos, K S; Mello, A C.E. [Chemistry Institute, Federal University of Rio Grande do Sul, UFRGS, Av. Bento Goncalves, 9500, Porto Alegre 91501-970 (Brazil); Liberman, S A; Oviedo, M A.S. [Braskem S.A., III Polo Petroquimico, Via Oeste, Lote 5, Triunfo 95853-000 (Brazil); Mauler, R.S., E-mail: mauler@iq.ufrgs.br [Chemistry Institute, Federal University of Rio Grande do Sul, UFRGS, Av. Bento Goncalves, 9500, Porto Alegre 91501-970 (Brazil)

    2011-08-25

    Highlights: {yields} Polypropylene montmorillonite (PP-MMT) produced at different processing conditions. {yields} Polypropylene Nanocomposites with higher increase on impact resistance. {yields} Higher enhancement on mechanical properties. - Abstract: Polypropylene montmorillonite (PP-MMT) nanocomposites have been prepared by using a co-rotating twin screw extruder. The effects of processing conditions at fixed clay content (5 wt%) on polymer properties were investigated by means of transmission electron microscopy (TEM), flexural modulus, izod impact, dynamic mechanical analysis (DMA), and differential scanning calorimetry (DSC). It was noticed that the morphology and the mechanical properties of polypropylene nanocomposites were affected by different screw shear configuration. The results showed that the higher enhancement on mechanical properties was obtained by medium shear intensity profile instead of high configuration. An exceptional increase (maximum of 282%) on impact resistance was observed.

  3. Effect of processing conditions on the mechanical and thermal properties of high-impact polypropylene nanocomposites

    International Nuclear Information System (INIS)

    Furlan, L.G.; Ferreira, C.I.; Dal Castel, C.; Santos, K.S.; Mello, A.C.E.; Liberman, S.A.; Oviedo, M.A.S.; Mauler, R.S.

    2011-01-01

    Highlights: → Polypropylene montmorillonite (PP-MMT) produced at different processing conditions. → Polypropylene Nanocomposites with higher increase on impact resistance. → Higher enhancement on mechanical properties. - Abstract: Polypropylene montmorillonite (PP-MMT) nanocomposites have been prepared by using a co-rotating twin screw extruder. The effects of processing conditions at fixed clay content (5 wt%) on polymer properties were investigated by means of transmission electron microscopy (TEM), flexural modulus, izod impact, dynamic mechanical analysis (DMA), and differential scanning calorimetry (DSC). It was noticed that the morphology and the mechanical properties of polypropylene nanocomposites were affected by different screw shear configuration. The results showed that the higher enhancement on mechanical properties was obtained by medium shear intensity profile instead of high configuration. An exceptional increase (maximum of 282%) on impact resistance was observed.

  4. Effect of Bi on graphite morphology and mechanical properties of heavy section ductile cast iron

    Directory of Open Access Journals (Sweden)

    Song Liang

    2014-03-01

    Full Text Available To improve the mechanical properties of heavy section ductile cast iron, bismuth (Bi was introduced into the iron. Five castings with different Bi content from 0 to 0.014 wt.% were prepared; and four positions in the casting from the edge to the center, with different solidification cooling rates, were chosen for microstructure observation and mechanical properties test. The effect of the Bi content on the graphite morphology and mechanical properties of heavy section ductile cast iron were investigated. Results show that the tensile strength, elongation and impact toughness at different positions in the five castings decrease with a decrease in cooling rate. With an increase in Bi content, the graphite morphology and the mechanical properties at the same position are improved, and the improvement of mechanical properties is obvious when the Bi content is no higher than 0.011wt.%. But when the Bi content is further increased to 0.014wt.%, the improvement of mechanical properties is not obvious due to the increase of chunky graphite number and the aggregation of chunky graphite. With an increase in Bi content, the tensile fracture mechanism is changed from brittle to mixture ductile-brittle fracture.

  5. Heat treatment effect on the mechanical properties of industrial drawn copper wires

    International Nuclear Information System (INIS)

    Beribeche, Abdellatif; Boumerzoug, Zakaria; Ji, Vincent

    2013-01-01

    In this present investigation, the mechanical properties of industrial drawn copper wires have been studied by tensile tests. The effect of prior heat treatments at 500°C on the drawn wires behavior was the main goal of this investigation. We have found that the mechanical behavior of drawn wires depends strongly on those treatments. SEM observations of the wire cross section after tensile tests have shown that the mechanism of rupture was mainly controlled by the void formation

  6. Effects of Radiation on Mechanical Properties of Poly (butylene succinate) and Cassava Starch Blends

    International Nuclear Information System (INIS)

    Hemvichian, K.; Dechasasawat, K.; Kangsumrith, W.; Suwanmala, P.

    2014-01-01

    This research compared the effects of gamma and electron beam irradiation at different doses on the mechanical properties of polymer blends between poly(butylene succinate) (PBS) and cassava starch. Two types of starch were used to prepare thermoplastic starch (TPS), native cassava starch and hydrophobic starch. PBS/TPS blends were compounded at five different weight ratios using a twin-screw extruder. Mechanical properties and degradation were evaluated in comparison to unirradiated samples. Results indicated that the incorpora- tion of TPS prepared from native cassava starch decreased the mechanical properties of PBS/TPS blends, whereas the addition of TPS prepared from hydrophobic starch improved the mechanical properties of the blends. In addition, the maximum mechanical properties of PBS/TPS blends were achieved when samples were exposed to irradiation at 120 kGy. Using soil burial evaluation, the degradation rate of blends was found to increase with the addition of TPS. Therefore we have demonstrated in this study that the type of TPS and irradiation treatment can significantly alter the mechanical properties and degradation of PBS/TPS blends.

  7. Effects of Microstructural Variability on Thermo-Mechanical Properties of a Woven Ceramic Matrix Composite

    Science.gov (United States)

    Goldsmith, Marlana B.; Sankar, Bhavani V.; Haftka, Raphael T.; Goldberg, Robert K.

    2013-01-01

    The objectives of this paper include identifying important architectural parameters that describe the SiC/SiC five-harness satin weave composite and characterizing the statistical distributions and correlations of those parameters from photomicrographs of various cross sections. In addition, realistic artificial cross sections of a 2D representative volume element (RVE) are generated reflecting the variability found in the photomicrographs, which are used to determine the effects of architectural variability on the thermo-mechanical properties. Lastly, preliminary information is obtained on the sensitivity of thermo-mechanical properties to architectural variations. Finite element analysis is used in combination with a response surface and it is shown that the present method is effective in determining the effects of architectural variability on thermo-mechanical properties.

  8. Effect of grain size on the high temperature mechanical properties of type 316LN stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, D. W.; Lee, Y. S.; Ryu, W. S.; Jang, J. S.; Kim, S. H.; Kim, W. G.; Cho, H. D.; Han, C. H

    2001-02-01

    Nitrogen increases the high temeprature mechanical properties and decreases grain size. The effect of nitrogen on the high temperature mechanical properties was investigated in the viewpoint of grain size. Tensile strength increases with the decrease of grain size and agrees with the Hall-Petch relationship. Effect of grain size on the low cycle fatigue life properties were investigated as measuring the fatigue life from the results which had been obtained by the constant strain rate and various strain range. There was no effect on the low cycle fatigue properties by the grain size. The time to rupture decreased with the increase of grain size. The steady state creep rate decreased to a minimum and then increased as the grain size increased. This result agrees with the result predicted from Garofalo equation. The rupture elongation at the intermediate grain size showed a minimum due to the cavity formed easily by carbide precipitates in the grain boundaries.

  9. Thermal creep effects on 20% cold worked AISI 316 mechanical properties

    International Nuclear Information System (INIS)

    Duncan, D.R.

    1980-09-01

    The effects of thermal creep on subsequent mechanical properties of 20% cold worked AISI 316 pressurized tubes were investigated. Specimens were subjected to temperatures of 811 to 977 0 K and stresses of 86 MPa to 276 MPa. This resulted in strains up to 1.3%. Subsequent mechanical property tests included load change stress rupture tests (original test pressure increased or decreased), uniaxial tensile tests, and temperature ramp burst tests. Load change stress rupture tests were consistent with predictions from isobaric tests, and thus, consistent with the linear life fraction rule. Tests with large stress increases and tests at 866 0 K displayed a tendency for earlier than predicted failure. Tensile and temperature ramp burst tests had only slight effects on material properties (property changes were attributed to thermal recovery). The test results showed that, under the conditions of investigation, dislocation structure recovery was the most significant effect of creep. 9 figures, 5 tables

  10. Effectiveness of feeding large kibbles with mechanical cleaning properties in cats with gingivitis

    NARCIS (Netherlands)

    Vrieling, HE; Theyse, LFH; van Winkelhoff, AJ; Dijkshoorn, NA; Logan, EI; Picovet, P

    2005-01-01

    Effectiveness of feeding large kibbles with mechanical cleaning properties in cats with gingivitis periodontal disease is the most common acquired oral disease in cats. it starts with plaque accumulation and gingivitis. The aim of this study was to evaluate the effectiveness of different types of

  11. Hygrothermal Effect on Mechanical and Fatigue Properties of laminated Lower Limb Socket and Bacteria Growth

    Directory of Open Access Journals (Sweden)

    Fadhel Abbas Abdullah

    2016-12-01

    Full Text Available In this work, hygrothermal effect on the mechanical and fatigue properties of prosthetic socket lamination and its effect on the bacteria growth were studied. Two laminations composite materials were used in manufacturing prosthetic socket by using vacuum device. The reinforced materials of these laminations were perlon and carbon nanopowder (CNP while the matrix material was polyurethane resin. Tests performed in this work were the moisture absorption properties test to calculate percent moisture content according to ASTM 5229, tensile and fatigue tests with and without the hygrothermal effect to find the mechanical and fatigue properties, and the bacteria growth test under the hygrothermal effect to calculate the number of bacteria on the laminations. The results showed that the lamination (10 perlon+1 wt % CNP has mechanical properties than lamination (10 perlon with and without hygrothermal effect. The mechanical and fatigue properties for the two laminations were decreasing with increasing temperature and moisture.. Adding carbon nanopowder to the lamination (10 perlon increased ultimate stress, modulus of elastic, and endurance limit by (1.36, 2.35, and2.72 time respectively. Finally, the results showed that the Staphylococcus aureus growth increases with increasing temperature and moisture on the two laminations used in manufacturing prosthetic socket, and adding carbon nanopowder also increased the Staphylococcus aureus growth on the lamination.

  12. Fibril morphology and tendon mechanical properties in patellar tendinopathy: effects of heavy slow resistance training

    DEFF Research Database (Denmark)

    Kongsgaard, Mads; Qvortrup, Klaus; Larsen, Jytte Overgaard

    2010-01-01

    BACKGROUND: Patellar tendinopathy is characterized by pathologic abnormalities. Heavy slow resistance training (HSR) is effective in the management of patellar tendinopathy, but the underlying functional mechanisms remain elusive. PURPOSE: To investigate fibril morphology and mechanical properties...... assessed symptoms/function and maximal tendon pain during activity. Tendon biopsy samples were analyzed for fibril density, volume fraction, and mean fibril area. Tendon mechanical properties were assessed using force and ultrasonography samplings. RESULTS: Patients improved in symptoms/function (P = .02...... area decreased (-26% +/- 21%, P = .04) in tendinopathic tendons after HSR. CONCLUSION: Fibril morphology is abnormal in tendinopathy, but tendon mechanical properties are not. Clinical improvements after HSR were associated with changes in fibril morphology toward normal fibril density and mean fibril...

  13. Effect of thermal history on mechanical properties of polyetheretherketone below the glass transition temperature

    Science.gov (United States)

    Cebe, Peggy; Chung, Shirley Y.; Hong, Su-Don

    1987-01-01

    The effect of thermal history on the tensile properties of polyetheretherketone neat resin films was investigated at different test temperatures (125, 25, and -100) using four samples: fast-quenched amorphous (Q); quenched, then crystallized at 180 C (C180); slowly cooled (for about 16 h) from the melt (SC); and air-cooled (2-3 h) from the melt (AC). It was found that thermal history significantly affects the tensile properties of the material below the glass transition. Fast quenched amorphous films were most tough, could be drawn to greatest strain before rupture, and undergo densification during necking; at the test temperature of -100 C, these films had the best ultimate mechanical properties. At higher temperatures, the semicrystalline films AC and C180 had properties that compared favorably with the Q films. The SC films exhibited poor mechanical properties at all test temperatures.

  14. Effect of different fibers on mechanical properties and ductility of alkali-activated slag cementitious material

    Science.gov (United States)

    Zhu, J.; Zheng, W. Z.; Qin, C. Z.; Xu, Z. Z.; Wu, Y. Q.

    2018-01-01

    The effect of different fibers on mechanical properties and ductility of alkali-activated slag cementitious material (AASCM) is studied. The research contents include: fiber type (plant fiber, polypropylene fiber), fiber content, mechanical property index, tensile stress-strain relationship curve, treating time. The test results showed that the compressive strength of two fibers reinforced AASCM was about 90 ~ 110MPa, and the tensile strength was about 3 ~ 5MPa. The reinforcement effect of polypropylene fiber is superior to that of plant fiber, and the mechanical properties of polypropylene fiber reinforced AASCM are superior to those of plant fiber, According to the comparison of SEM pictures, the plant fiber and polypropylene fiber are both closely bound with the matrix, and the transition zones are complete and close. Thus, it is proved that plant fiber and polypropylene fiber delay the crack extension and enhance the ductility of AASCM.

  15. The Effects of Shallow Cryogenic Process On The Mechanical Properties of AISI 4140 Steel

    Directory of Open Access Journals (Sweden)

    Eşref KIZILKAYA

    2018-03-01

    Full Text Available In this study, shallow cryogenic treatments were carried out for various holding time to AISI 4140 steel and the effects of heat treatment parameters on wear behavior, impact strength and tensile strength were investigated. Three different holding times were used for cryogenic heat treatments. After the cryogenic process, single tempering was applied. In addition, the abrasion tests were carried out at three different forces (5N, 10N and 15N at a constant slip speed (3.16 m / s and at three different slip distances (95 m, 190 m, 285 m. It has been determined that the shallow cryogenic process parameters significantly influence the mechanical properties of the AISI 4140 steel as a result of experimental studies., Low heat treatment times in cryogenic heat treatment have been found to have a positive effect on many mechanical properties, especially wear. The mechanical properties of the AISI 4140 steel can be optimized by controlling the shallow cryogenic heat treatment parameters.

  16. The effect of artificial accelerated weathering on the mechanical properties of maxillofacial polymers PDMS and CPE.

    Science.gov (United States)

    Eleni, P N; Krokida, M K; Polyzois, G L

    2009-06-01

    The effect of UVA-UVB irradiation on the mechanical properties of three different industrial types of polydimethylsiloxane and chlorinated polyethylene samples, used in maxillofacial prostheses, was investigated in this study. Mechanical properties and thermal analysis are commonly used to determine the structural changes and mechanical strength. An aging chamber was used in order to simulate the solar radiation and assess natural aging. Compression and tensile tests were conducted on a Zwick testing machine. Durometer Shore A hardness measurements were carried out in a CV digital Shore A durometer according to ASTM D 2240. Glass transition temperature was evaluated with a differential scanning calorimeter. Simple mathematical models were developed to correlate the measured properties with irradiation time. The effect of UVA-UVB irradiation on compressive behavior affected model parameters. Significant deterioration seems to occur due to irradiation in samples.

  17. Effect of stacking sequence on mechanical properties neem wood veneer plastic composites

    Science.gov (United States)

    Nagamadhu, M.; Kumar, G. C. Mohan; Jeyaraj, P.

    2018-04-01

    This study investigates the effect of wood veneer stacking sequence on mechanical properties of neem wood polymer composite (WPC) experimentally. Wood laminated samples were fabricated by conventional hand layup technique in a mold and cured under pressure at room temperature and then post cured at elevated temperature. Initially, the tensile, flexural, and impact test were conducted to understand the effect of weight fraction of fiber on mechanical properties. The mechanical properties have increased with the weight fraction of fiber. Moreover the stacking sequence of neem wood plays an important role. As it has a significant impact on the mechanical properties. The results indicated that 0°/0° WPC shows highest mechanical properties as compared to other sequences (90°/90°, 0°/90°, 45°/90°, 45°/45°). The Fourier Transform Infrared Spectroscopy (FTIR) Analysis were carried out to identify chemical compounds both in raw neem wood and neem wood epoxy composite. The microstructure raw/neat neem wood and the interfacial bonding characteristics of neem wood composite investigated using Scanning electron microscopy images.

  18. DTA and DSC study on the effect of mechanical dispersion on poly(tetrafluorethylene properties

    Directory of Open Access Journals (Sweden)

    Dumitraşa Mihai

    2014-12-01

    Full Text Available Poly(tetrafluorethylene particles were obtained by mechanical processing of the formed polymer (Teflon bar. In order to assess the effect of mechanical wear on polymer properties, their melting and crystallization behaviour was investigated by DSC and DTA, and the results were compared to the ones obtained for the native polymer. An increase of the crystallinity degree and an accentuated decrease of the average molecular weight were found for the samples submitted to mechanical wear, as a result of mechanical degradation of the polymer

  19. Simulated effect on the compressive and shear mechanical properties of bionic integrated honeycomb plates.

    Science.gov (United States)

    He, Chenglin; Chen, Jinxiang; Wu, Zhishen; Xie, Juan; Zu, Qiao; Lu, Yun

    2015-05-01

    Honeycomb plates can be applied in many fields, including furniture manufacturing, mechanical engineering, civil engineering, transportation and aerospace. In the present study, we discuss the simulated effect on the mechanical properties of bionic integrated honeycomb plates by investigating the compressive and shear failure modes and the mechanical properties of trabeculae reinforced by long or short fibers. The results indicate that the simulated effect represents approximately 80% and 70% of the compressive and shear strengths, respectively. Compared with existing bionic samples, the mass-specific strength was significantly improved. Therefore, this integrated honeycomb technology remains the most effective method for the trial manufacturing of bionic integrated honeycomb plates. The simulated effect of the compressive rigidity is approximately 85%. The short-fiber trabeculae have an advantage over the long-fiber trabeculae in terms of shear rigidity, which provides new evidence for the application of integrated bionic honeycomb plates. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Effects of various defects on the mechanical properties of black phosphorene

    Science.gov (United States)

    Nguyen, Danh-Truong; Le, Minh-Quy; Nguyen, Van-Trang; Bui, Thanh-Lam

    2017-12-01

    The present work investigates the effects of seven types of defects on the mechanical properties of black phosphorene. Molecular dynamics finite element method with Stillinger-Weber potential is used to simulate the uniaxial tensile tests of the pristine and defective black phosphorene sheets. Young's modulus, fracture stress, and fracture strain of the pristine and defective black phosphorene sheets are estimated. Comparison of the influence of different types of defects on the mechanical response of black phosphorene is considered. Fracture mechanism of various defective black phosphorene sheets is also analyzed. It is found that effect of the defects on Young's modulus of black phosphorene is insignificant. In contrast, due to defects fracture stress and fracture strain can reduce up to 53% and 69%, respectively. Results provide a landscape on the mechanical properties of defective black phosphorene and are useful for the design of nanodevices with black phosphorene in future applications.

  1. The effect of saturation of the mechanical properties of tuff at Yucca Mountain

    International Nuclear Information System (INIS)

    Karakouzian, M.; Hudyma, N.

    1996-01-01

    This study investigates the effect of saturation on the mechanical properties, namely compressive strength and Young's Modulus, of Tiva Canyon welded tuff and Topopah Spring welded tuff from the Nevada Test Site. Unconfined compression tests on air dried and saturated specimens show that saturation lowers both the average compressive strength and the average Young's Modulus of Topopah Spring and Tiva Canyon tuff specimens. Saturation increases the variability of the mechanical properties of Topopah Spring tuff and the variability of the compressive strength of Tiva Canyon tuff

  2. The effect of tungsten on mechanical properties of the Ti-9% Al-3% Zr alloy

    International Nuclear Information System (INIS)

    Nartova, T.T.; Grigor'ev, I.P.; Stepanov, Yu.N.; Tarasova, O.B.

    1979-01-01

    The effect of tungsten (from 0 to 10 %) on mechanical properties of the ternary Ti-9 %, Al-3 % Zr alloy, has been studied. The microstructure, tensile properties at 20 and 600 deg C and Vickers hardness in as-forged and as-annealed states have been studied. The experiments have shown that the ultimate strength increases with tungsten content. Titanium alloys with 9 % Al and 3 % Zr in the case of varying tungsten content at 20 deg C fracture by brittle mechanism. The dUctility of the annealed alloy does not rise at 20 deg C, but at the test temperature of 600 deg C the alloy becomes ductile

  3. Physico-mechanical properties of coir fiber/LDPE composites: Effect of chemical treatment and compatibilizer

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, Nirupama; Agarwal, Vijay Kumar; Sihha, Shishir [Indian Institute of Technology Roorkee, Uttrakhand (India)

    2015-12-15

    Coir fiber/low density polyethylene (LDPE) composites were fabricated with different fiber loading (10- 30 wt%) using compression molding technique. A fiber loading of 20 wt% was found optimum, with maximum mechanical properties. Further, the effect of fiber treatment (alkali and acrylic acid) and compatibilizer (MA-g-LDPE) incorporation on the mechanical and water absorption properties of the LDPE composites were studied and compared. The results showed that MA-g-LDPE incorporation into untreated and treated fiber composites led to improved mechanical properties and water resistance compared with the same composite formulation without MA-g-LDPE. However, treated fiber composites with MA-g-LDPE showed lower mechanical properties than untreated fiber without MA-g- LDPE, due to the removal of hydroxyl groups from the hemicellulose and lignin region of the fiber and degradation of fibers by chemical attack. From SEM studies on the tensile fractured composite samples, a good relationship has been observed between the morphological and mechanical properties.

  4. Effect of pH on the morphology, mechanical and optical properties of ...

    Indian Academy of Sciences (India)

    Administrator

    Indian Academy of Sciences. 1419. Effect of pH on the morphology, mechanical and optical properties of .... 1 mm and the focal length ( f ) of the convex lens used to focus the laser beam was 300 mm. In the present work,. 20 laser shots ...

  5. Effect of particle size of granules on some mechanical properties of ...

    African Journals Online (AJOL)

    Solid dosage forms are invariably multiparticulate systems of heterogenous particle size distribution. The purpose of this study was to investigate the effect of particle size distribution of paracetamol granules on some tablet mechanical properties of paracetamol tablets. Granules were formed by wet massing paracetamol ...

  6. Humidity Effects on Soluble Core Mechanical and Thermal Properties (Polyvinyl Alcohol/Microballoon Composite)

    Science.gov (United States)

    1993-01-01

    This document constitutes the final report for the study of humidity effects and loading rate on soluble core (PVA/MB composite material) mechanical and thermal properties. This report describes test results, procedures employed, and any unusual occurrences or specific observations associated with this test program.

  7. Effect of brief heat-curing on microstructure and mechanical properties in fresh cement based mortars

    International Nuclear Information System (INIS)

    Ballester, P.; Hidalgo, A.; Marmol, I.; Morales, J.; Sanchez, L.

    2009-01-01

    The effect of temperature on fresh mortar and cement paste was evaluated by simulating the curing conditions of external buildings plastering applied under extremely hot weather. The specimens were heated at controlled temperatures in the 40-80 o C range by exposure to IR radiation over short periods. The effect of soaking for a short time was also examined. The results of compressive strength tests, scanning electron microscopy, infrared spectroscopy and mercury porosimetry helped to characterize the mechanical and physico-chemical properties of the studied sample. Early age behaviour (28 days) in neat cement was barely affected by the temperature. By contrast, exposure to high temperatures caused significant microstructural changes in the mortar. However, successive soaking over short periods was found to reactivate the mechanism of curing and restore the expected mechanical properties. Based on the results, application of cement based mortar at high temperatures is effective when followed by a short, specific soaking process.

  8. Effect of calcium deficiency on the mechanical properties of hydroxyapatite crystals

    International Nuclear Information System (INIS)

    Viswanath, B.; Shastry, V.V.; Ramamurty, U.; Ravishankar, N.

    2010-01-01

    The deterioration of the mechanical properties of bone with age is related to several factors including the structure, organization and chemistry of the constituent phases; however, the relative contribution of each of these factors is not well understood. In this study, we have investigated the effect of chemistry (calcium deficiency) on the mechanical properties of single crystals of hydroxyapatite. Single crystals of stoichiometric crystals grown by the flux method and calcium-deficient platelet crystals grown using wet chemical methods were used as model systems. Using nanoindentation, we show that calcium deficiency leads to an 80% reduction in the hardness and elastic modulus and at least a 75% reduction in toughness in plate-shaped hydroxyapatite crystals. Measurement of local mechanical properties using nanoindentation and nanoscale chemistry through elemental mapping in a transmission electron microscope points to a direct correlation between the observed spatial variation in composition and the large scatter in the measured hardness and modulus values.

  9. High energy radiation effects on mechanical properties of butyl rubber compounds

    International Nuclear Information System (INIS)

    Pozenato, Cristina A.; Scagliusi, Sandra R.; Cardoso, Elisabeth C.L.; Lugao, Ademar B.

    2013-01-01

    The high energy radiation on butyl rubber compounds causes a number of chemical reactions that occur after initial ionization and excitation events. These reactions lead to changes in molecular mass of the polymer through scission and crosslinking of the molecules, being able to affect the physical and mechanical properties. Butyl rubber has excellent mechanical properties and oxidation resistance as well as low gas and water vapor permeability. Due to all these properties butyl rubber is widely used industrially and particularly in tires manufacturing. In accordance with various authors, the major effect of high energy, such as gamma rays in butyl rubber, is the yielding of free-radicals along with changes in mechanical properties. There were evaluated effects imparted from high energy radiation on mechanical properties of butyl rubber compounds, non-irradiated and irradiated with 25 kGy, 50 kGy, 150 kGy and 200 kGy. It was also observed a sharp reducing in stress rupture and elongation at break for doses higher than 50 kGy, pointing toward changes in polymeric chain along build-up of free radicals and consequent degradation. (author)

  10. Mechanical properties of HDPE/UHMWPE blends: effect of filler loading and filler treatment.

    Science.gov (United States)

    Lai, K L K; Roziyanna, A; Ogunniyi, D S; Zainal, Arifin M I; Azlan, Ariffin A

    2004-05-01

    Various blend ratios of high-density polyethylene (HDPE) and ultra high molecular weight polyethylene (UHMWPE) were prepared with the objective of determining their suitability as biomaterials. In the unfilled state, a blend of 50/50 (HDPE/UHMWPE) ratio by weight was found to yield optimum properties in terms of processability and mechanical properties. Hydroxyapatite (HA) was compounded with the optimum blend ratio. The effects of HA loading, varied from 0 to 50wt% for both filled and unfilled blends were tested for mechanical properties. It was found that the inclusion of HA in the blend led to a remarkable improvement of mechanical properties compared to the unfilled blend. In order to improve the bonding between the polymer blend and the filler, the HA used was chemically treated with a coupling agent known as 3-(trimethoxysiyl) propyl methacrylate and the treated HA was mixed into the blend. The effect of mixing the blend with silane-treated HA also led to an overall improvement of mechanical properties.

  11. Microstructural effects on mechanical properties data for elevated-temperature reactor design

    International Nuclear Information System (INIS)

    Klueh, R.L.; Brinkman, C.R.; Sikka, V.K.

    1977-01-01

    We are presently generating mechanical property design data for types 304 and 316 stainless steels and 2 1/4 Cr-1 Mo-steel. In addition to the determination of design data on single heats of the steel, we are also examining mechanical property data variation. One of the objectives of this work is the acquisition of an understanding of the cause of mechanical properties variations from heat-to-heat. In types 304 and 316 stainless steels, much of the heat-to-heat variation has been explained in terms of variations in carbon and nitrogen concentration and grain size; a relationship was found between these quantities and the ultimate tensile strength. Since it was possible to relate the ultimate tensile strength to the 1000 hr rupture life, the creep-rupture properties could also be related to the variations in chemical composition. The variations in properties for a ferritic steel such as 2 1/4 Cr-1 Mo steel are again chemistry dependent, but here heat treatment is of crucial importance. Even when a single heat treatment is considered, however, slight variations in heat treatment procedures (by different vendors) can lead to distinct differences in properties. To understand the effect of variations in heat treatment on 2 1/4 Cr-1 Mo steel, we made studies on a heat of steel given different 'annealing' treatments. Distinct differences in creep and tensile properties were observed for the different heat treatments. These differences could be explained in terms of the types of precipitation reactions that occur in the material during the heat treatment. Even when identical heat treatments are given to two heats of 2 1/4 Cr-1 Mo steel of similar chemical composition, however, large property differences are sometimes observed. This was noted for fatigue properties, and here some minor element effect on hardenability of the steel may be playing a role

  12. Effects of irradiation and mechanical stress on the superconducting properties of candidate magnet conductors

    International Nuclear Information System (INIS)

    Snead, C.L. Jr.; Luhman, T.

    1980-01-01

    The effects of radiation damage on the superconducting critical properties of candidate magnet materials are reviewed. Neutron, and charged-particle irradiation results are covered. The discussion is restricted to effects in NbTi and the A15-compound superconductors. The utility of these conductors in radiation fields is first explored by defining the magnitude of critical-property changes with the fluence of various irradiating particles. The physical mechanisms that couple the irradiation defects to the observed critical-property changes are discussed. Annealing/recovery data on irradiated materials are included where they pertain to the understanding of the physical mechanisms involved, and thereby to the desirability of magnet annealing in actual operating circumstances

  13. Effects of Inorganic Fillers on the Thermal and Mechanical Properties of Poly(lactic acid).

    Science.gov (United States)

    Liu, Xingxun; Wang, Tongxin; Chow, Laurence C; Yang, Mingshu; Mitchell, James W

    Addition of filler to polylactic acid (PLA) may affect its crystallization behavior and mechanical properties. The effects of talc and hydroxyapatite (HA) on the thermal and mechanical properties of two types of PLA (one amorphous and one semicrystalline) have been investigated. The composites were prepared by melt blending followed by injection molding. The molecular weight, morphology, mechanical properties, and thermal properties have been characterized by gel permeation chromatography (GPC), scanning electron microscope (SEM), instron tensile tester, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). It was found that the melting blending led to homogeneous distribution of the inorganic filler within the PLA matrix but decreased the molecular weight of PLA. Regarding the filler, addition of talc increased the crystallinity of PLA, but HA decreased the crystallinity of PLA. The tensile strength of the composites depended on the crystallinity of PLA and the interfacial properties between PLA and the filler, but both talc and HA filler increased the toughness of PLA.

  14. Electron-beam irradiation effects on mechanical properties of PEEK/CF composite

    International Nuclear Information System (INIS)

    Sasuga, Tsuneo; Seguchi, Tadao

    1989-01-01

    Carbon fibre-reinforced composite (PEEK/CF) using polyarylether-ether-ketone (PEEK) as a matrix material was prepared and electron-beam irradiation effects on the mechanical properties at low and high temperatures were studied. The flexural strength and modulus of the unirradiated PEEK/CF were almost the same as those of carbon fibre-reinforced composites with epoxide resin. The mechanical properties at room temperature were little affected by irradiation up to 180 MGy, but in the test at 77K the strength of the specimens irradiated over 100 MGy was slightly decreased. The mechanical properties of the unirradiated specimen decreased with increasing testing temperature, but the high-temperature properties were improved by irradiation, i.e. the strength measured at 413K for the specimen irradiated with 120 MGy almost reached the value for the unirradiated specimen measured at room temperature. It was apparent from the viscoelastic measurement that the improvement of mechanical properties at high temperature resulted from the high-temperature shift of the glass transition of the matrix PEEK caused by radiation-induced cross-linking. (author)

  15. Effects of Inorganic Fillers on the Thermal and Mechanical Properties of Poly(lactic acid

    Directory of Open Access Journals (Sweden)

    Xingxun Liu

    2014-01-01

    Full Text Available Addition of filler to polylactic acid (PLA may affect its crystallization behavior and mechanical properties. The effects of talc and hydroxyapatite (HA on the thermal and mechanical properties of two types of PLA (one amorphous and one semicrystalline have been investigated. The composites were prepared by melt blending followed by injection molding. The molecular weight, morphology, mechanical properties, and thermal properties have been characterized by gel permeation chromatography (GPC, scanning electron microscope (SEM, instron tensile tester, thermogravimetric analysis (TGA, differential scanning calorimetry (DSC, and dynamic mechanical analysis (DMA. It was found that the melting blending led to homogeneous distribution of the inorganic filler within the PLA matrix but decreased the molecular weight of PLA. Regarding the filler, addition of talc increased the crystallinity of PLA, but HA decreased the crystallinity of PLA. The tensile strength of the composites depended on the crystallinity of PLA and the interfacial properties between PLA and the filler, but both talc and HA filler increased the toughness of PLA.

  16. The Effects of Ribose on Mechanical and Physicochemical Properties of Cold Water Fish Gelatin Films

    Directory of Open Access Journals (Sweden)

    Neda Javadian

    2014-06-01

    Full Text Available Native fish gelatin has some disadvantages such as high hydrophilic, and solubility in cold water. Mixing with other biopolymers and crosslinking by sugars may improve functional properties of fish gelatin. So in this research, the effects of ribose were investigated on moisture sorption isotherm, solubility in water, and mechanical properties of cold water fish gelatin (CWFG films. Ribose sugar was incorporated into CWFG solutions at different concentrations (e.g. 0, 2, 4, and 6% w/w dried gelatin. Physicochemical properties such as water solubility, moisture sorption isotherm and mechanical properties of the films were measured according to ASTM standards. Results showed that incorporation of ribose sugar significantly improved functional properties of CWFG films. Solubility, moisture content and monolayer water content of the matrixes were decreased by increasing the ribose contents. Mechanical properties of biocomposites were improved more than 20% and moisture sorption isotherm curve significantly shifted to lower moisture contents. The results of this study could be explored for commercial use, depending on industrial needs for either production of edible films or for packaging purposes.

  17. Effect of Cu addition on microstructure and mechanical properties of 15%Cr super martensitic stainless steel

    International Nuclear Information System (INIS)

    Ye, Dong; Li, Jun; Jiang, Wen; Su, Jie; Zhao, Kunyu

    2012-01-01

    Highlights: ► Cu contributes to refine the grains. ► Cu solutes in matrix under quenching and precipitates as ε-Cu during tempering. ► Cu promotes the kinetics of reversed austenite formation. ► Mechanical properties are significantly influenced by austenite amount. ► Cu alloyed super martensitic stainless steel exhibits greatly improved mechanical properties. -- Abstract: The effect of adding different content of Cu (0 wt.%, 1.5 wt.% and 3 wt.%) to the 15%Cr super martensitic stainless steel (SMSS) was investigated using optical microscope, scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD). Its consequence on mechanical properties was examined to clarify the role of Cu in the tested steels. The experimental results indicate that the microstructures of three tested steels are tempered martensite, retained austenite and reversed austenite; two kinds of austenites are dispersedly distributed among martensite matrix. Cu can solute in matrix under quenching condition and can precipitate as Cu-rich nanometer phase (ε-Cu) during tempering. Cu is helpful for the grain refinement and to promote the formation of reversed austenite during tempering. The maximum volume fraction of austenite is 55.9% in the steel with 3 wt.% Cu, which is responsible for the improvement of ductility. The results of the mechanical properties tests reveal that the mechanical properties are significantly influenced by the volume fraction of austenite. Cu can cause solid solution strengthening, precipitation strengthening and grain refinement strengthening in SMSS. Cu alloyed super martensitic stainless steel exhibits greatly improved mechanical properties.

  18. Study of the ionizing radiation effect on the polyamide 6,6 mechanical properties

    International Nuclear Information System (INIS)

    Colombo, Maria Aparecida da Silva

    2004-01-01

    Polyamide 6,6 due to its excellent mechanical, thermal and electrical properties and its great performance in multiple industrial applications is considered one of the most important engineering polymers. However, in specific applications, some of its properties need to be improved by means additives or fillers to reach the required properties increasing its final cost. By these considerations, the aim of this work was to apply the ionizing radiation to improve the natural mechanical properties of polyamide 6,6. Also, to evaluate the irradiation parameters, and the mechanical performance of the irradiated polymer in order to use the cross-linking, induced by ionizing radiation, as substitute of additives and fillers. Row polyamide 6,6 samples, for mechanical tests, were prepared by injection molded and then irradiated with high energetic electrons to reach doses of 70, 100, 150, and 200 kGy. The mechanical performance, of non-irradiated and irradiated samples, was evaluated by tensile strength, impact, hardness and wear measurements. Furthermore, hardness and wear tests were carried out with samples, which were immersed in petroleum and sea water for 6 months. The experimental results have shown that, in the studied dose range, the tensile strength increases 25%, the hardness Shore D 15%, the impact values diminished by 80% and the wear values decreased 20 times between 0 and 200 kGy. The effect of the petroleum and sea water were shown mainly in the nonirradiated samples. (author)

  19. EFFECT OF THERMO-MECHANICAL TREATMENT ON PROPERTIES OF PARICA PLYWOODS (Schizolobium amazonicum Huber ex Ducke

    Directory of Open Access Journals (Sweden)

    Mírian de Almeida Costa

    Full Text Available ABSTRACT Thermo-mechanical treatment is a technique for wood modification in which samples are densified by means of heat and mechanical compression, applied perpendicularly to fibers, which under different combinations of time, temperature, and pressure increases wood density and thus improve some of its properties. This study aimed to treat thermo-mechanically parica plywood and observe the effects on its physical and mechanical properties. Specimens were submitted to two treatments, 120 and 150 ºC, remaining under pressure for seven minutes and, subsequently, under zero pressure for 15 minutes. Results showed a significant increase in specific mass from 0.48 g cm-3 to an average of 0.56 g cm-3, and a compression ratio of about 31.7% on average. Physical properties also varied significantly and results showed that treated samples swelled and absorbed more water than those untreated, leading to a greater thickness non-return rate. This indicates the proposed thermal treatments did not release the internal compressive stress generated during panel pressing, not improving its dimensional stability as a result. On the other hand, mechanical properties were positively affected, leading to an increase of 27.5% and 51.8% in modulus of rupture after treatments at 120 and 150 ºC, respectively. Modulus of elasticity and glue-line shear strength did not vary statistically and Janka hardness was 29.7% higher after treatment at 150 ºC.

  20. Effect of cobalt doping on the mechanical properties of ZnO nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Vahtrus, Mikk; Šutka, Andris [Institute of Physics, University of Tartu, W. Ostwaldi 1, 50412 Tartu (Estonia); Polyakov, Boris [Institute of Solid State Physics, University of Latvia, Kengaraga 8, LV-1063 Riga (Latvia); Oras, Sven; Antsov, Mikk [Institute of Physics, University of Tartu, W. Ostwaldi 1, 50412 Tartu (Estonia); Doebelin, Nicola [RMS Foundation, Bischmattstrasse 12, Bettlach 2544 (Switzerland); Institute of Geological Sciences, University of Bern, Baltzerstrasse 1–3, Bern 3012 (Switzerland); Lõhmus, Rünno; Nõmmiste, Ergo [Institute of Physics, University of Tartu, W. Ostwaldi 1, 50412 Tartu (Estonia); Vlassov, Sergei, E-mail: vlassovs@ut.ee [Institute of Physics, University of Tartu, W. Ostwaldi 1, 50412 Tartu (Estonia)

    2016-11-15

    In this work, we investigate the influence of doping on the mechanical properties of ZnO nanowires (NWs) by comparing the mechanical properties of pure and Co-doped ZnO NWs grown in similar conditions and having the same crystallographic orientation [0001]. The mechanical characterization included three-point bending tests made with atomic force microscopy and cantilever beam bending tests performed inside scanning electron microscopy. It was found that the Young's modulus of ZnO NWs containing 5% of Co was approximately a third lower than that of the pure ZnO NWs. Bending strength values were comparable for both materials and in both cases were close to theoretical strength indicating high quality of NWs. Dependence of mechanical properties on NW diameter was found for both doped and undoped ZnO NWs. - Highlights: •Effect of Co doping on the mechanical properties of ZnO nanowires is studied. •Co substitutes Zn atoms in ZnO crystal lattice. •Co addition affects crystal lattice parameters. •Co addition results in significantly decreased Young's modulus of ZnO. •Bending strength for doped and undoped wires is close to the theoretical strength.

  1. Effective Mechanical Property Estimation of Composite Solid Propellants Based on VCFEM

    Directory of Open Access Journals (Sweden)

    Liu-Lei Shen

    2018-01-01

    Full Text Available A solid rocket motor is one of the critical components of solid missiles, and its life and reliability mostly depend on the mechanical behavior of a composite solid propellant (CSP. Effective mechanical properties are critical material constants to analyze the structural integrity of propellant grain. They are estimated by a numerical method that combines the Voronoi cell finite element method (VCFEM and the homogenization method in the present paper. The correctness of this combined method has been validated by comparing with a standard finite element method and conventional theoretical models. The effective modulus and the effective Poisson’s ratio of a CSP varying with volume fraction and component material properties are estimated. The result indicates that the variations of the volume fraction of inclusions and the properties of the matrix have obvious influences on the effective mechanical properties of a CSP. The microscopic numerical analysis method proposed in this paper can also be used to provide references for the design and the analysis of other large volume fraction composite materials.

  2. Rheological Characteristics of Cement Grout and its Effect on Mechanical Properties of a Rock Fracture

    Science.gov (United States)

    Liu, Quansheng; Lei, Guangfeng; Peng, Xingxin; Lu, Chaobo; Wei, Lai

    2018-02-01

    Grouting reinforcement, which has an obvious strengthening effect on fractured rock mass, has been widely used in various fields in geotechnical engineering. The rheological properties of grout will greatly affect its diffusion radius in rock fractures, and the water-cement ratio is an important factor in determining the grouting flow patterns. The relationship between shear stress and shear rate which could reflect the grout rheological properties, the effects of water-cement ratio, and temperature on the rheological properties of grouting was studied in the laboratory. Besides, a new method for producing fractured rock specimens was proposed and solved the problem of producing natural fractured rock specimens. To investigate the influences of grouting on mechanical properties of a rock fracture, the fractured rock specimens made using the new method were reinforced by grouting on the independent designed grouting platform, and then normal and tangential mechanical tests were carried out on fractured rock specimens. The results showed that the mechanical properties of fractured rock mass are significantly improved by grouting, the peak shear strength and residual strength of rock fractures are greatly improved, and the resistance to deformation is enhanced after grouting. Normal forces affect the tangential behavior of the rock fracture, and the tangential stress strength increases with normal forces. The strength and stability of fractured rock mass are increased by grouting reinforcement.

  3. Effect of Sb-Modification on the Microstructure and Mechanical Properties of Secondary Alloy 319

    Directory of Open Access Journals (Sweden)

    Medlen D.

    2016-06-01

    Full Text Available 319 alloy has been selected for the study in the present work due to its wide use in many applications. 319 alloy is used in automotive and aerospace industry for the complicated castings which must comply high strength requirements. In practice, the most common elements with the modifying effect are strontium, sodium and antimony. The addition of these elements leads to a change in the shape of eutectic silicon, resulting in an increase of the mechanical characteristics and the microstructure. An experimental program has been undertaken to explore the effect of antimony on chosen mechanical properties and the microstructure of investigated alloy. An analysis of the results of these experimental works is made in order to determine an optimum Sb (Al-10% Sb addition to produce material exhibiting desirable properties. Experimental works have showed that the addition of the Al-10% Sb results in similar or even higher mechanical properties than the conventional 319 alloy. Based on the carried out experiments the best combination of mechanical properties has been achieved by the addition of 2 000 ppm Al-10% Sb.

  4. Effect of electron beam irradiation on thermal and mechanical properties of aluminum based epoxy composites

    Science.gov (United States)

    Visakh, P. M.; Nazarenko, O. B.; Sarath Chandran, C.; Melnikova, T. V.; Nazarenko, S. Yu.; Kim, J.-C.

    2017-07-01

    The epoxy resins are widely used in nuclear and aerospace industries. The certain properties of epoxy resins as well as the resistance to radiation can be improved by the incorporation of different fillers. This study examines the effect of electron beam irradiation on the thermal and mechanical properties of the epoxy composites filled with aluminum nanoparticles at percentage of 0.35 wt%. The epoxy composites were exposed to the irradiation doses of 30, 100 and 300 kGy using electron beam generated by the linear electron accelerator ELU-4. The effects of the doses on thermal and mechanical properties of the aluminum based epoxy composites were investigated by the methods of thermal gravimetric analysis, tensile test, and dynamic mechanical analysis. The results revealed that the studied epoxy composites showed good radiation resistance. The thermal and mechanical properties of the aluminum based epoxy composites increased with increasing the irradiation dose up to 100 kGy and decreased with further increasing the dose.

  5. Effect of LED-LCU light irradiance distribution on mechanical properties of resin based materials

    Energy Technology Data Exchange (ETDEWEB)

    Magalhães Filho, T.R.; Weig, K.M. [Faculdade de Odontologia, Universidade Federal Fluminense, Rua São Paulo 28, CEP 24020-150 Niterói (Brazil); Engenharia Metalúrgica e de Materiais (COPPE), Universidade Federal do Rio de Janeiro, CP 68505, CEP: 21941-972 Rio de Janeiro (Brazil); Costa, M.F. [Engenharia Metalúrgica e de Materiais (COPPE), Universidade Federal do Rio de Janeiro, CP 68505, CEP: 21941-972 Rio de Janeiro (Brazil); Werneck, M.M. [Engenharia Elétrica (COPPE), Universidade Federal do Rio de Janeiro, CP 68504, CEP: 21941-972 Rio de Janeiro (Brazil); Barthem, R.B. [Instituto de Física, Universidade Federal do Rio de Janeiro, CP 68528, CEP: 21941-972 Rio de Janeiro (Brazil); Costa Neto, C.A., E-mail: celio@metalmat.ufrj.br [Engenharia Metalúrgica e de Materiais (COPPE), Universidade Federal do Rio de Janeiro, CP 68505, CEP: 21941-972 Rio de Janeiro (Brazil)

    2016-06-01

    The objective of this study is to analyze the light power distribution along the tip end of the light guide of three LED-LCUs (Light Curing Units) and to evaluate its effect on the mechanical properties of a polymer based dental composite. Firstly, the light power distribution over the whole area of LED-LCU light guide surface was analyzed by three methods: visual projection observation, spectral measurement and optical spectral analysis (OSA). The light power distribution and the total irradiance were different for the three LEDs used, but the wavelength was within the camphorquinone absorption spectrum. The use of a blank sheet was quite on hand to make a qualitative analysis of a beam, and it is costless. Secondly, specimens of a hybrid composite with approximately 8 mm diameter and 2 mm thickness were produced and polymerized by 20 s exposition time to each LED-LCU. Thirdly, the elastic modulus (E) and hardness (HV) were measured throughout the irradiated area by instrumented micro-indentation test (IIT), allowing to correlate localized power and mechanical properties. Both E and HV showed to be very sensitive to local power and wavelength dependent, but they followed the beam power profile. It was also shown that the mechanical properties could be directly correlated to the curing process. Very steep differences in mechanical properties over very short distances may impair the material performance, since residual stresses can easily be built over it. - Highlights: • A resin based composite (RBC) was polymerized by three different Light Emitting Diodes. • Each LED had its beam profile visually, wavelength and power analyzed. • The effective polymerization power (EPP) varied from 28% to 52% of the total beam power. • Wavelength seems to be as relevant as power in the light curing process. • Mechanical properties depend on the simultaneous effect of wavelength and power.

  6. Effect of LED-LCU light irradiance distribution on mechanical properties of resin based materials

    International Nuclear Information System (INIS)

    Magalhães Filho, T.R.; Weig, K.M.; Costa, M.F.; Werneck, M.M.; Barthem, R.B.; Costa Neto, C.A.

    2016-01-01

    The objective of this study is to analyze the light power distribution along the tip end of the light guide of three LED-LCUs (Light Curing Units) and to evaluate its effect on the mechanical properties of a polymer based dental composite. Firstly, the light power distribution over the whole area of LED-LCU light guide surface was analyzed by three methods: visual projection observation, spectral measurement and optical spectral analysis (OSA). The light power distribution and the total irradiance were different for the three LEDs used, but the wavelength was within the camphorquinone absorption spectrum. The use of a blank sheet was quite on hand to make a qualitative analysis of a beam, and it is costless. Secondly, specimens of a hybrid composite with approximately 8 mm diameter and 2 mm thickness were produced and polymerized by 20 s exposition time to each LED-LCU. Thirdly, the elastic modulus (E) and hardness (HV) were measured throughout the irradiated area by instrumented micro-indentation test (IIT), allowing to correlate localized power and mechanical properties. Both E and HV showed to be very sensitive to local power and wavelength dependent, but they followed the beam power profile. It was also shown that the mechanical properties could be directly correlated to the curing process. Very steep differences in mechanical properties over very short distances may impair the material performance, since residual stresses can easily be built over it. - Highlights: • A resin based composite (RBC) was polymerized by three different Light Emitting Diodes. • Each LED had its beam profile visually, wavelength and power analyzed. • The effective polymerization power (EPP) varied from 28% to 52% of the total beam power. • Wavelength seems to be as relevant as power in the light curing process. • Mechanical properties depend on the simultaneous effect of wavelength and power.

  7. Effect of elastic and plastic tensile mechanical loading on the magnetic properties of NGO electrical steel

    Energy Technology Data Exchange (ETDEWEB)

    Leuning, N., E-mail: nora.leuning@iem.rwth-aachen.de [Institute of Electrical Machines, RWTH Aachen University, D-52062 Aachen (Germany); Steentjes, S. [Institute of Electrical Machines, RWTH Aachen University, D-52062 Aachen (Germany); Schulte, M.; Bleck, W. [Steel Institute, RWTH Aachen University, D-52072 Aachen (Germany); Hameyer, K. [Institute of Electrical Machines, RWTH Aachen University, D-52062 Aachen (Germany)

    2016-11-01

    The magnetic properties of non-grain-oriented (NGO) electrical steels are highly susceptible to mechanical stresses, i.e., residual, external or thermal ones. For rotating electrical machines, mechanical stresses are inevitable and originate from different sources, e.g., material processing, machine manufacturing and operating conditions. The efficiency and specific losses are largely altered by different mechanical stress states. In this paper the effect of tensile stresses and plastic deformations on the magnetic properties of a 2.9 wt% Si electrical steel are studied. Particular attention is paid to the effect of magnetic anisotropy, i.e., the influence of the direction of applied mechanical stress with respect to the rolling direction. Due to mechanical stress, the induced anisotropy has to be evaluated as it is related to the stress-dependent magnetostriction constant and the grain alignment. - Highlights: • A detailed look at magnetic anisotropy of FeSi NGO electrical steel. • Study of magnetic behavior under elastic as well as plastic tensile stresses. • Correlation of magnetic behavior with microscopic deformation mechanisms. • Discussion of detrimental and beneficial effects of external stresses. • Loss separation at different polarizations and frequencies under increasing stress.

  8. Effect of elastic and plastic tensile mechanical loading on the magnetic properties of NGO electrical steel

    International Nuclear Information System (INIS)

    Leuning, N.; Steentjes, S.; Schulte, M.; Bleck, W.; Hameyer, K.

    2016-01-01

    The magnetic properties of non-grain-oriented (NGO) electrical steels are highly susceptible to mechanical stresses, i.e., residual, external or thermal ones. For rotating electrical machines, mechanical stresses are inevitable and originate from different sources, e.g., material processing, machine manufacturing and operating conditions. The efficiency and specific losses are largely altered by different mechanical stress states. In this paper the effect of tensile stresses and plastic deformations on the magnetic properties of a 2.9 wt% Si electrical steel are studied. Particular attention is paid to the effect of magnetic anisotropy, i.e., the influence of the direction of applied mechanical stress with respect to the rolling direction. Due to mechanical stress, the induced anisotropy has to be evaluated as it is related to the stress-dependent magnetostriction constant and the grain alignment. - Highlights: • A detailed look at magnetic anisotropy of FeSi NGO electrical steel. • Study of magnetic behavior under elastic as well as plastic tensile stresses. • Correlation of magnetic behavior with microscopic deformation mechanisms. • Discussion of detrimental and beneficial effects of external stresses. • Loss separation at different polarizations and frequencies under increasing stress.

  9. Effectiveness of Fiber Reinforcement on the Mechanical Properties and Shrinkage Cracking of Recycled Fine Aggregate Concrete

    Science.gov (United States)

    Nam, Jeongsoo; Kim, Gyuyong; Yoo, Jaechul; Choe, Gyeongcheol; Kim, Hongseop; Choi, Hyeonggil; Kim, Youngduck

    2016-01-01

    This paper presents an experimental study conducted to investigate the effect of fiber reinforcement on the mechanical properties and shrinkage cracking of recycled fine aggregate concrete (RFAC) with two types of fiber—polyvinyl alcohol (PVA) and nylon. A small fiber volume fraction, such as 0.05% or 0.1%, in RFAC with polyvinyl alcohol or nylon fibers was used for optimum efficiency in minimum quantity. Additionally, to make a comparative evaluation of the mechanical properties and shrinkage cracking, we examined natural fine aggregate concrete as well. The test results revealed that the addition of fibers and fine aggregates plays an important role in improving the mechanical performance of the investigated concrete specimens as well as controlling their cracking behavior. The mechanical properties such as compressive strength, splitting tensile strength, and flexural strength of fiber-reinforced RFAC were slightly better than those of non-fiber-reinforced RFAC. The shrinkage cracking behavior was examined using plat-ring-type and slab-type tests. The fiber-reinforced RFAC showed a greater reduction in the surface cracks than non-fiber-reinforced concrete. The addition of fibers at a small volume fraction in RFAC is more effective for drying shrinkage cracks than for improving mechanical performance. PMID:28773256

  10. The Effect of Void Shape on the Mechanical Properties of Rock

    International Nuclear Information System (INIS)

    D.O. Potyondy

    2006-01-01

    The bonded-particle model for rock (Potyondy and Cundall, 2004) represents rock by a dense packing of non-uniform-sized circular or spherical particles that are bonded together at their contact points and whose mechanical behavior is simulated by the distinct-element method using the two- and three-dimensional programs PFC2D and PFC3D. A bonded-particle model of lithophysal tuff has been used to study the effect of lithophysae (hollow, bubble-like voids) on the mechanical properties (Young's modulus and unconfined compressive strength) of this rock, and to quantify the variability of these properties. The model reproduces the failure mechanisms observed in the laboratory and exhibits a reduction of strength and modulus with increasing lithophysal volume fraction. The effect of void shape on mechanical properties is studied by inserting randomly distributed voids of simple shape (circle, triangle and star) and by inserting voids corresponding with lithophysal cavities identified in panel maps of the walls of a tunnel through this material. These studies address tunnel-stability issues associated with mechanical degradation of planned emplacement drifts at Yucca Mountain, which is the designated site for the proposed US high-level nuclear waste repository

  11. Effectiveness of Fiber Reinforcement on the Mechanical Properties and Shrinkage Cracking of Recycled Fine Aggregate Concrete.

    Science.gov (United States)

    Nam, Jeongsoo; Kim, Gyuyong; Yoo, Jaechul; Choe, Gyeongcheol; Kim, Hongseop; Choi, Hyeonggil; Kim, Youngduck

    2016-02-26

    This paper presents an experimental study conducted to investigate the effect of fiber reinforcement on the mechanical properties and shrinkage cracking of recycled fine aggregate concrete (RFAC) with two types of fiber-polyvinyl alcohol (PVA) and nylon. A small fiber volume fraction, such as 0.05% or 0.1%, in RFAC with polyvinyl alcohol or nylon fibers was used for optimum efficiency in minimum quantity. Additionally, to make a comparative evaluation of the mechanical properties and shrinkage cracking, we examined natural fine aggregate concrete as well. The test results revealed that the addition of fibers and fine aggregates plays an important role in improving the mechanical performance of the investigated concrete specimens as well as controlling their cracking behavior. The mechanical properties such as compressive strength, splitting tensile strength, and flexural strength of fiber-reinforced RFAC were slightly better than those of non-fiber-reinforced RFAC. The shrinkage cracking behavior was examined using plat-ring-type and slab-type tests. The fiber-reinforced RFAC showed a greater reduction in the surface cracks than non-fiber-reinforced concrete. The addition of fibers at a small volume fraction in RFAC is more effective for drying shrinkage cracks than for improving mechanical performance.

  12. Effect of friction stir welding parameters on microstructure and mechanical properties of DSS–Cu joints

    Energy Technology Data Exchange (ETDEWEB)

    Shokri, V., E-mail: v.shokri@modares.ac.ir [Department of Mechanical Engineering, Tarbiat Modarres University, Tehran (Iran, Islamic Republic of); Sadeghi, A. [School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Sadeghi, M.H. [Department of Mechanical Engineering, Tarbiat Modarres University, Tehran (Iran, Islamic Republic of)

    2017-05-02

    Dissimilar joining of copper to duplex stainless steel (DSS) is challenging at high temperatures of fusion welding owing to the large difference in physical properties of the base metals. To reduce negative effects of welding at high temperatures, solid state welding at lower temperatures has been proposed. To study different effects of welding parameters (rotation speed, travel speed and tool offset) on weld zone microstructure and mechanical properties butt joints of a copper alloy and duplex stainless steel (DSS) were produced by friction stir welding (FSW). It has been found that heat input generated by the interaction of different welding conditions has a significant effect on the formation of a brittle intermetallic at the interface and eventually the final mechanical properties. At low heat inputs, mixing of the two sides is insufficient and metallurgical bonding is weak; while at high heat inputs, the thickness of the formed intermetallic is too thick which causes stress concentration at the interface and premature failure. An optimum welding condition was found (rotation speed of 1200 rpm, travel speed of 30 mm/min and tool offset of 0.5 mm) which almost reached the mechanical properties of the Cu-alloy monolayer.

  13. The effect of natural weathering on the mechanical, morphological and thermal properties of high impact polystyrene (HIPS)

    International Nuclear Information System (INIS)

    Sahin, Tuelin; Sinmazcelik, Tamer; Sahin, Senol

    2007-01-01

    The effect of natural weathering on the mechanical, morphological and thermal properties on the high impact polystyrene (HIPS) and cold drawn HIPS are investigated. After natural weathering period of 8760 h, under known meteorological parameters, the changes in mechanical properties are investigated by using tensile, instrumented impact and hardness tests. Thermo-mechanical properties are characterized by using thermomechanical analysis (TMA) and melt flow index (MFI). Fractured surfaces of the materials are investigated by scanning electron microscope (SEM). Natural weathering effects on fracture mechanisms are discussed by means of fractographical analysis. Remarkable morphological changes were observed especially at the surface of the material. This results in dramatic loss in mechanical properties

  14. Effects of Static Recrystallization and Precipitation on Mechanical Properties of 00Cr12 Ferritic Stainless Steel

    Science.gov (United States)

    Shao, Yi; Liu, Chenxi; Yue, Tengxiao; Liu, Yongchang; Yan, Zesheng; Li, Huijun

    2018-05-01

    The 00Cr12 ferritic stainless steel samples were isothermally held at different temperatures in the range of 700 °C to 1000 °C to investigate the effect of static recrystallization and precipitation on mechanical properties, such as microhardness, tensile strength, and yield strength. The results show that the formation of the fine recrystallized grain, as well as precipitation, coarsening, and dissolution of the second-phase particles, influences the mechanical properties remarkably. The fine recrystallized grain can provide a positive grain boundary-strengthening effect in the sample under a relatively high holding temperature. Coarsening and dissolution of M23C6 result in partial depletion of precipitate hardening. In contrast, the size and number density of MX particles are almost constant, regardless of the holding temperature; therefore, it can provide a better precipitation-hardening effect.

  15. Effect of reduced graphene oxide-carbon nanotubes hybrid nanofillers in mechanical properties of polymer nanocomposites

    Science.gov (United States)

    Sa, Kadambinee; Mahakul, Prakash C.; Subramanyam, B. V. R. S.; Raiguru, Jagatpati; Das, Sonali; Alam, Injamul; Mahanandia, Pitamber

    2018-03-01

    Graphene and carbon nanotubes (CNTs) have tremendous interest as reinforcing fillers due to their excellent physical properties. However, their reinforcing effect in polymer matrix is limited due to agglomeration of graphene and CNTs within the polymer matrix. Mechanical properties by the admixture of reduced graphene oxide (rGO) and CNTs in Poly (methyl methacrylate) (PMMA) prepared by solution mixing method has been investigated. The prepared samples are characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and Raman spectroscopy. The hybrid composite shows improvement in the mechanical properties compared to rGO/PMMA and MWCNTs/PMMA composites due to better interaction between rGO-MWCNTs and polymer matrix.

  16. The effect of particles in different sizes on the mechanical properties of spray formed steel composites

    DEFF Research Database (Denmark)

    Petersen, Kenneth; Pedersen, A. S.; Pryds, N.

    2000-01-01

    particle size of 46 and 134 μm were carried out with respect to their mechanical properties e.g. wear resistance and tensile strength. It was found that the addition of Al2O3 particles to the steel improves its wear properties and reduces the elongation and tensile strength of the material......The main objective of the work was to investigate the effect of addition of ceramic particles with different size distributions on the mechanical properties, e.g. wear resistance and tensile strength, of spray formed materials. The experiments were carried out in a spray-forming unit at Risø...... National Laboratory, Denmark, where composites with a low alloyed boron steel (0.2 wt.% carbon) matrix containing alumina particles were produced. A comparison between cast hot-rolled material without particles, spray formed material without particles and the spray formed composites with an average ceramic...

  17. Structure-property effects on mechanical, friction and wear properties of electron modified PTFE filled EPDM composite

    Directory of Open Access Journals (Sweden)

    2009-01-01

    Full Text Available Tribological properties of Ethylene-Propylene-Diene-rubber (EPDM containing electron modified Polytetrafluoroethylene (PTFE have been investiagted with the help of pin on disk tribometer without lubrication for a testing time of 2 hrs in atmospheric conditions at a sliding speed and applied normal load of 0.05 m•s–1 and FN = 1 N, respectively. Radiation-induced chemical changes in electron modified PTFE powders were analyzed using Electron Spin Resonance (ESR and Fourier Transform Infrared (FTIR specroscopy to characterize the effects of compatibility and chemical coupling of modified PTFE powders with EPDM on mechanical, friction and wear properties. The composites showed different friction and wear behaviour due to unique morphology, dispersion behaviour and radiation functionalization of PTFE powders. In general, EPDM reinforced with electron modified PTFE powder demonstrated improvement both in mechanical and tribological properties. However, the enhanced compatibility of PTFE powder resulting from the specific chemical coupling of PTFE powder with EPDM has been found crucial for mechanical, friction and wear properties.

  18. Effect of tumor therapeutic irradiation on the mechanical properties of teeth tissue

    International Nuclear Information System (INIS)

    Fraenzel, W.; Gerlach, R.; Hein, H.J.; Schaller, H.G.

    2006-01-01

    Tumor irradiation of the head-neck area is accompanied by the development of a so-called radiation caries in the treated patients. In spite of conservative therapeutic measures, the process results in tooth destruction. The present study investigated the effects of irradiation on the demineralization and remineralization of the dental tissue. For this purpose, retained third molars were prepared and assigned either to a test group, which was exposed to fractional irradiation up to 60 Gy, or to a non-irradiated control group. Irradiated and non-irradiated teeth were then demineralized using acidic hydroxyl-cellulose gel; afterwards the teeth were remineralized using either Bifluorid12 registered or elmex gelee registered . The nanoindentation technique was used to measure the mechanical properties, hardness and elasticity, of the teeth in each of the conditions. The values were compared to the non-irradiated control group. Irradiation decreased dramatically the mechanical parameters of enamel and dentine. In non-irradiated teeth, demineralization had nearly the same effects of irradiation on the mechanical properties. In irradiated teeth, the effects of demineralization were negligible in comparison to non-irradiated teeth. Remineralization with Bifluorid12 registered or elmex gelee registered led to a partial improvement of the mechanical properties of the teeth. The enamel was more positively affected, by remineralization than the dentine. (orig.)

  19. Effect of tumor therapeutic irradiation on the mechanical properties of teeth tissue

    Energy Technology Data Exchange (ETDEWEB)

    Fraenzel, W. [Dept. of Physics, Martin Luther Univ. Halle (Germany); Gerlach, R. [Univ. Clinic and Policlinic for Radiation Therapy, Martin Luther Univ. Halle (Germany); Hein, H.J. [Univ. Clinic and Policlinic for Orthopaedics and Physical Medicine, Martin Luther Univ. Halle (Germany); Schaller, H.G. [Dept. of Operative Dentistry and Periodontology, Martin Luther Univ. Halle (Germany)

    2006-07-01

    Tumor irradiation of the head-neck area is accompanied by the development of a so-called radiation caries in the treated patients. In spite of conservative therapeutic measures, the process results in tooth destruction. The present study investigated the effects of irradiation on the demineralization and remineralization of the dental tissue. For this purpose, retained third molars were prepared and assigned either to a test group, which was exposed to fractional irradiation up to 60 Gy, or to a non-irradiated control group. Irradiated and non-irradiated teeth were then demineralized using acidic hydroxyl-cellulose gel; afterwards the teeth were remineralized using either Bifluorid12 {sup registered} or elmex gelee {sup registered}. The nanoindentation technique was used to measure the mechanical properties, hardness and elasticity, of the teeth in each of the conditions. The values were compared to the non-irradiated control group. Irradiation decreased dramatically the mechanical parameters of enamel and dentine. In non-irradiated teeth, demineralization had nearly the same effects of irradiation on the mechanical properties. In irradiated teeth, the effects of demineralization were negligible in comparison to non-irradiated teeth. Remineralization with Bifluorid12 {sup registered} or elmex gelee {sup registered} led to a partial improvement of the mechanical properties of the teeth. The enamel was more positively affected, by remineralization than the dentine. (orig.)

  20. Effect of segregations on mechanical properties and crack propagation in spring steel

    Directory of Open Access Journals (Sweden)

    B. Žužek

    2015-10-01

    Full Text Available Considerable efforts have been made over the last decades to improve performance of spring steels, which would increase the service time of springs and also allow vehicles weight reduction. There are different possibilities of improving properties of spring steels, from modifying the chemical composition of steels to optimizing the deformation process and changing the heat treatment parameters. Another way of improving steel properties is through refining the microstructure and reducing amount of inclusions. Therefore, the focus of the current investigation was to determine the effect of more uniform and cleaner microstructure obtained through electro-slag remelting (ESR of steel on the mechanical and dynamic properties of spring steel, with special focus on the resistance to fatigue crack propagation. Effect of the microstructure refinement was evaluated in terms of tensile strength, elongation, fracture and impact toughness, and fatigue resistance under bending and tensile loading. After the mechanical tests the fracture surfaces of samples were analyzed using scanning electron microscope (SEM and the influence of microstructure properties on the crack propagation and crack propagation resistance was studied. Investigation was performed on hot rolled, soft annealed and vacuum heat treated 51CrV4 spring steel produced by conventional continuous casting and compared with steel additional refined through ESR. Results shows that elimination of segregations and microstructure refinement using additional ESR process gives some improvement in terms of better repeatability and reduced scattering, but on the other hand it has negative effect on crack propagation resistance and fatigue properties of the spring steel.

  1. Effect of solution treatment temperature and cooling rate on the mechanical properties of tungsten heavy alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kumari, Anjali, E-mail: anjalikumari1261@gmail.com; Prabhu, G.; Sankaranarayana, M.; Nandy, T.K.

    2017-03-14

    The present study investigates the effect of solution treatment temperature and cooling rate on mechanical properties of a tungsten heavy alloy (89.6W-6.2Ni-1.8Fe-2.4Co). In addition to water quenching, rapid argon quenching has been attempted in this study since it is a relatively cleaner process and it can be used in conjunction with vacuum treatment. Since in these alloys, there is a possibility of incomplete dissolution of intermetallics or segregation of impurities during heat treatment, which results in scatter in the mechanical properties, it was decided that the solution treatment temperature for both water and argon quenching would be varied from 1100 to 1250 °C in order to see its effect on the microstructure and mechanical properties. Solution treatment at varying temperatures followed by water quenching resulted in tensile strength ranging from 908 to 921 MPa and % elongation varied from 19% to 26%. On the other hand, the argon quenching heat treatment resulted in tensile strength in the range of 871–955 MPa and % elongation from 9% to 25%. No significant trend with respect to solution treatment temperature on tensile properties was seen in both argon and water quenched samples. % elongation to failure and impact values of water quenched specimens were better than those of argon quenched specimens for a given solution treatment temperature. The impact values appeared to improve with increasing solution treatment temperature in water quenched condition. The properties were correlated with underlying microstructure and fractographs of the failed specimens. The study showed the argon quenching may not be appropriate for the heat treatment of heavy alloys since it results in inferior mechanical properties as compared to water quenching.

  2. Effects of heat treatment on the microstructure and mechanical properties of AA2618 DC cast alloy

    International Nuclear Information System (INIS)

    Elgallad, E.M.; Shen, P.; Zhang, Z.; Chen, X.-G.

    2014-01-01

    Highlights: • The microstructure and mechanical properties of AA2618 DC cast alloy were studied. • The Al 2 CuMg, Al 2 Cu, Al 7 Cu 4 Ni, Al 7 Cu 2 (Fe,Ni) and Al 9 FeNi phases were identified. • Solution treatment at 530 °C for 5 h is the optimum solution treatment. • Different combinations of strength and ductility can be achieved. • The strengthening of AA2618 DC cast alloy was caused by GPB zones and S′ phase. - Abstract: Direct chill (DC) cast ingot plates of AA2618 alloy have been increasingly used for large-mold applications in the plastics and automotive industries. The effects of different heat treatments on the microstructure and mechanical properties of AA2618 DC cast alloy were investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and hardness and tensile testing. The as-cast microstructure contained a considerable amount of coarse intermetallic phases, including Al 2 CuMg, Al 2 Cu, Al 7 Cu 4 Ni, Al 7 Cu 2 (Fe,Ni) and Al 9 FeNi, resulting in poor mechanical properties. Solution treatment at 530 °C for 5 h dissolved the first three phases into the solid solution and consequently improved the mechanical properties of the alloy. By utilizing the appropriate aging temperature and time, different combinations of strength and ductility could be obtained to fulfill the design requirements of large-mold applications. The strengthening of AA2618 DC cast alloy under the aging conditions studied was caused by GPB zones and S′ precipitates. The evolution of both precipitates in terms of their size and density was observed to have a significant effect on the mechanical properties of the alloy

  3. Effects of bioleaching on the mechanical and chemical properties of waste rocks

    Science.gov (United States)

    Yin, Sheng-Hua; Wu, Ai-Xiang; Wang, Shao-Yong; Ai, Chun-Ming

    2012-01-01

    Bioleaching processes cause dramatic changes in the mechanical and chemical properties of waste rocks, and play an important role in metal recovery and dump stability. This study focused on the characteristics of waste rocks subjected to bioleaching. A series of experiments were conducted to investigate the evolution of rock properties during the bioleaching process. Mechanical behaviors of the leached waste rocks, such as failure patterns, normal stress, shear strength, and cohesion were determined through mechanical tests. The results of SEM imaging show considerable differences in the surface morphology of leached rocks located at different parts of the dump. The mineralogical content of the leached rocks reflects the extent of dissolution and precipitation during bioleaching. The dump porosity and rock size change under the effect of dissolution, precipitation, and clay transportation. The particle size of the leached rocks decreased due to the loss of rock integrity and the conversion of dry precipitation into fine particles.

  4. The effect of organoclay type on morphology and mechanical properties of polypropylene films: comparative study

    International Nuclear Information System (INIS)

    Gama, D.B.; Calado, J.F.; Duarte, I.S.; Silva, S.M.L.; Andrade, D.L.A.C.S.

    2012-01-01

    This paper aims to compare the effect of the type of organoclay on morphological and mechanical properties of polypropylene films. Thus, were employed two organobentonite synthesized by NanoPol/UFCG (APOC and APOCF) and a organo montmorillonite Cloisite 20A (C20A) from Southern Clay Products (Texas/USA). The PP films and the PP/organoclay hybrids were prepared in a ChillRoll extruder - 16 AX Plastics and characterized by X-ray diffraction and mechanical properties. The results indicate that the incorporation of organobentonite (APOC and APOCF) and organo montmorillonite (C20A) resulted in the formation of PP nanocomposites with predominantly intercalated morphologies. Also indicate that the mechanical behavior of the films obtained with the three clays (APOC APOCF and C20A) was similar suggesting that the organobentonite, modified with national technology, raw material of low cost when compared to commercial organo montmorillonite, can be a viable alternative in the preparation of PP films. (author)

  5. Effect of organically modified clay on mechanical properties, cytotoxicity and bactericidal properties of poly(ɛ-caprolactone) nanocomposites

    Science.gov (United States)

    Kumar, Sachin; Mishra, Anupam; Chatterjee, Kaushik

    2014-12-01

    The objective of this study was to evaluate the use of organically-modified clay nanoparticles in poly(ɛ-caprolactone) (PCL) for developing biodegradable composites. PCL nanocomposites reinforced with two different types of organically-modified clay (Cloisite 30B, C30B and Cloisite 93A, C93A) were prepared by melt-mixing. Morphology of PCL/clay nanocomposites characterized by scanning electron microscopy indicated good dispersion of nanoclay in the PCL matrix. Reinforcement of nanoclay in PCL enhanced mechanical properties without affecting thermal and degradation properties of PCL. Cytocompatibility of PCL/clay nanocomposites was studied using both osteoblasts and endothelial cells in vitro. Both composites (PCL/C30B and PCL/C93A) were cytotoxic with high toxicity observed for C30B even at low content of 1 wt %. The cytotoxicity was found to arise due to leachables from PCL/clay composites. Electrical conductivity measurements of aqueous media confirmed leaching of cationic surfactant from the PCL/clay composites PCL matrix. Both composites were found to be bactericidal but C30B was more effective than C93A. Taken together, it was observed that organically-modified nanoclay as fillers in PCL improves mechanical properties and imparts bactericidal properties but with increased risk of toxicity. These PCL/clay composites may be useful as stronger packaging material with antibacterial properties but are not suited as biomedical implants or for food packaging applications.

  6. Effect of high pressure on the mechanical properties of lithium disilicate glass ceramic

    International Nuclear Information System (INIS)

    Buchner, Silvio; Lepienski, Carlos M.; Jr, Paulo C. Soares; Balzaretti, Naira M.

    2011-01-01

    Research highlights: → High pressure densification of LS2 decreases the mechanical properties. → Densification of LS2 at high temperature improves the mechanical properties. → Hardness and elastic modulus of LS2 densified at high temperature are notably high. - Abstract: Lithium disilicate glass has been submitted to a high pressure treatment associated to a heat treatment, and the effects of densification and crystallization at high pressure on the mechanical properties were evaluated. The hardness and elastic modulus were examined by instrumented indentation using a Berkovich tip. The crack pattern morphology after indentation with a cube corner indenter was also investigated. The hardness and elastic modulus of the samples submitted to high pressure at room temperature decreased with increasing pressure. The hardness and elastic modulus of the samples submitted simultaneously to high pressure (up to 7.7 GPa) and high temperature increased noticeably. The amount, length and type of cracks induced by the cube corner tip changed with increasing pressure. These results indicate that the high temperature treatment under high pressure improved the mechanical properties of LS 2 .

  7. Water Absorption Behaviour and Its Effect on the Mechanical Properties of Flax Fibre Reinforced Bioepoxy Composites

    Directory of Open Access Journals (Sweden)

    E. Muñoz

    2015-01-01

    Full Text Available In the context of sustainable development, considerable interest is being shown in the use of natural fibres like as reinforcement in polymer composites and in the development of resins from renewable resources. This paper focuses on eco-friendly and sustainable green composites manufacturing using resin transfer moulding (RTM process. Flax fibre reinforced bioepoxy composites at different weight fractions (40 and 55 wt% were prepared in order to study the effect of water absorption on their mechanical properties. Water absorption test was carried out by immersion specimens in water bath at room temperature for a time duration. The process of water absorption of these composites was found to approach Fickian diffusion behavior. Diffusion coefficients and maximum water uptake values were evaluated; the results showed that both increased with an increase in fibre content. Tensile and flexural properties of water immersed specimens were evaluated and compared to dry composite specimens. The results suggest that swelling of flax fibres due to water absorption can have positive effects on mechanical properties of the composite material. The results of this study showed that RTM process could be used to manufacture natural fibre reinforced composites with good mechanical properties even for potential applications in a humid environment.

  8. Effect of SMAT on microstructural and mechanical properties of AA2024

    International Nuclear Information System (INIS)

    Tadge, Prashant; Sasikumar, C.

    2016-01-01

    In recent days surface mechanical attrition treatment (SMAT) had attracted the attention of researchers as it produces a nano-crystalline surface with improved mechanical properties. In the present study Al-4%Cu alloy used in automobile and aerospace application is subjected to surface mechanical attrition treatment using steel shots. The microstructural changes introduced on the surface of the Al alloy was investigated using Scanning Electron Microscopy (SEM). The secondary phases formed during the SMAT process is been investigated using EDX and XRD analysis. The effects of SMAT on the mechanical properties were analyzed using a tensile testing. The SMA treatment had resulted in severe plastic deformation of the surface, thereby yielded a nanocrystalline surface with a grain size of 30 to 50 nm. Further, it is also found that the SMAT produced ultra nanocrystalline particles of Cu_2Al dispersed uniformly into α-Al matrix. These microstructural changes had resulted in considerable change in the mechanical properties of these alloys. The tensile strength of these alloys had increased from ∼212 MPa to 303 MPa while the fracture toughness increased up to 28% in 10 minutes of SMAT.

  9. Effects of aniline concentrations on the electrical and mechanical properties of polyaniline polyvinyl alcohol blends

    Directory of Open Access Journals (Sweden)

    J. Bhadra

    2017-07-01

    Full Text Available In this work, we present an exclusive study on the effect of the feeding ratio of the monomer (aniline on the structural, thermal, mechanical and electrical properties of polyaniline (PANI polyvinyl alcohol (PVA blends. The films obtained from the blends are characterised to determine their surface properties and structural morphology (elemental analysis, SEM and FTIR, thermal properties (TGA and DSC and optical properties (UV–Vis spectroscopy. We study the effects of aniline on the mechanical and electrical properties of the composites by performing tensile, four probe and A.C. conductivity measurements, respectively. The SEM images reveal a heterogeneous distribution of conductive PANI particles in the continuous PVA matrix. During this experiment, the tensile strength of the blend films is maintained with an increase in the amount of aniline (up to 25 wt%, and this behaviour is attributed to intermolecular hydrogen bonding between PANI and PVA in the presence of the surfactant DBSA. The potential attraction of the experiment lies in the nature of the conductivity (of the blend films, which is found to increase from 10−8 to 10−3 S/cm with a percolation threshold of 0.78 wt%.

  10. Effect of gamma and neutron irradiation on the mechanical properties of Spectralon™ porous PTFE

    Energy Technology Data Exchange (ETDEWEB)

    Gourdin, William H., E-mail: gourdin1@llnl.gov [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA USA (United States); Datte, Philip; Jensen, Wayne; Khater, Hesham; Pearson, Mark [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA USA (United States); Girard, Sylvain [Laboratoire Hubert Curien − UMR CNRS 5516, 18 rue du Pr. Benoît Lauras, F-42000 Saint Etienne (France); Paillet, Philippe; Alozy, Eric [CEA, DAM, DIF, F-91297 Arpajon (France)

    2016-11-15

    Highlights: • The effects of neutrons and gammas on PTFE are equivalent for a given absorbed dose. • A neutron fluence of 10{sup 13} n/cm{sup 2} corresponds to a gamma dose of 200 Gy. • The dose-to-fluence conversion factor is approximately 5 × 10{sup 10} n/(cm{sup 2}-Gy). • Irradiation in a low-oxygen environment enhances loads and elongations. • Mechanical properties of PTFE will deteriorate at a neutron fluence of 10{sup 13} n/cm{sup 2}. - Abstract: We establish a correspondence between the mechanical properties (maximum load and failure elongation) of Spectralon™ porous PTFE irradiated with 14 MeV neutrons and 1.17 and 1.33 MeV gammas from a cobalt-60 source. From this correspondence we infer that the effects of neutrons and gammas on this material are approximately equivalent for a given absorbed dose.

  11. Crystallization and mechanical properties of reinforced PHBV composites using melt compounding: Effect of CNCs and CNFs.

    Science.gov (United States)

    Jun, Du; Guomin, Zhao; Mingzhu, Pan; Leilei, Zhuang; Dagang, Li; Rui, Zhang

    2017-07-15

    Nanocellulose reinforced poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) composites were prepared using melt compounding. The effects of nanocellulose types (CNCs and CNFs) and nanocellulose content (1, 2, 3, 4, 5, 6 and 7wt%) on the crystallization, thermal and mechanical properties of PHBV composites were systematically compared in this study. The thermal stability of PHBV composites was improved by both CNCs and CNFs. CNFs with a higher thermal stability leaded to a higher thermal stability of PHBV composites. Both CNCs and CNFs induced a reduction in the crystalline size of PHBV spherulites. Furthermore, CNCs could act as a better nucleating agent for PHBV than did CNFs. CNCs and CNFs showed reinforcing effects in PHBV composites. At the equivalent content of nanocellulose, CNCs led to a higher tensile modulus of PHBV composites than did CNFs. 1wt% CNCs/PHBV composites exhibited the most optimum mechanical properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Electron beam crosslinked gels-Preparation, characterization and their effect on the mechanical, dynamic mechanical and rheological properties of rubbers

    International Nuclear Information System (INIS)

    Mitra, Suman; Chattopadhyay, Santanu; Sabharwal, Sunil; Bhowmick, Anil K.

    2010-01-01

    Electron beam (EB) crosslinked natural rubber (NR) gels were prepared by curing NR latex with EB irradiation over a range of doses from 2.5 to 20 kGy using butyl acrylate as sensitizer. The NR gels were systematically characterized by solvent swelling, dynamic light scattering, mechanical and dynamic mechanical properties. These gels were introduced in virgin NR and styrene butadiene rubber (SBR) matrices at 2, 4, 8 and 16 phr concentration. Addition of the gels improved the mechanical and dynamic mechanical properties of NR and SBR considerably. For example, 16 phr of 20 kGy EB-irradiated gel-filled NR showed a tensile strength of 3.53 MPa compared to 1.85 MPa of virgin NR. Introduction of gels in NR shifted the glass transition temperature to a higher temperature. A similar effect was observed in the case of NR gel-filled SBR systems. Morphology of the gel-filled systems was studied with atomic force microscopy. The NR gels also improved the processability of the virgin rubbers greatly. Both the shear viscosity and the die swell values of EB-irradiated gel-filled NR and SBR were lower than their virgin counterparts as investigated by capillary rheometer.

  13. Electron beam crosslinked gels-Preparation, characterization and their effect on the mechanical, dynamic mechanical and rheological properties of rubbers

    Energy Technology Data Exchange (ETDEWEB)

    Mitra, Suman; Chattopadhyay, Santanu [Rubber Technology Centre, Indian Institute of Technology, Kharagpur 721302 (India); Sabharwal, Sunil [Radiation Technology Development Section, Bhabha Atomic Research Center, Trombay, Mumbai 400085 (India); Bhowmick, Anil K., E-mail: anilkb@rtc.iitkgp.ernet.i [Rubber Technology Centre, Indian Institute of Technology, Kharagpur 721302 (India)

    2010-03-15

    Electron beam (EB) crosslinked natural rubber (NR) gels were prepared by curing NR latex with EB irradiation over a range of doses from 2.5 to 20 kGy using butyl acrylate as sensitizer. The NR gels were systematically characterized by solvent swelling, dynamic light scattering, mechanical and dynamic mechanical properties. These gels were introduced in virgin NR and styrene butadiene rubber (SBR) matrices at 2, 4, 8 and 16 phr concentration. Addition of the gels improved the mechanical and dynamic mechanical properties of NR and SBR considerably. For example, 16 phr of 20 kGy EB-irradiated gel-filled NR showed a tensile strength of 3.53 MPa compared to 1.85 MPa of virgin NR. Introduction of gels in NR shifted the glass transition temperature to a higher temperature. A similar effect was observed in the case of NR gel-filled SBR systems. Morphology of the gel-filled systems was studied with atomic force microscopy. The NR gels also improved the processability of the virgin rubbers greatly. Both the shear viscosity and the die swell values of EB-irradiated gel-filled NR and SBR were lower than their virgin counterparts as investigated by capillary rheometer.

  14. Effect of ion irradiation on the surface, structural and mechanical properties of brass

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Shahbaz; Bashir, Shazia, E-mail: shaziabashir@gcu.edu.pk; Ali, Nisar; Umm-i-Kalsoom,; Yousaf, Daniel; Faizan-ul-Haq,; Naeem, Athar; Ahmad, Riaz; Khlaeeq-ur-Rahman, M.

    2014-04-01

    Highlights: • Brass targets were exposed to carbon ions of energy 2 MeV. • The effect of ion dose has been investigated. • The surface morphology is investigated by SEM analysis. • XRD analysis is performed to reveal structural modification. • Mechanical properties were investigated by tensile testing and microhardness testing. - Abstract: Modifications to the surface, structural and mechanical properties of brass after ion irradiation have been investigated. Brass targets were bombarded by carbon ions of 2 MeV energy from a Pelletron linear accelerator for various fluences ranging from 56 × 10{sup 12} to 26 × 10{sup 13} ions/cm{sup 2}. A scanning electron microscope and X-ray diffractometer were utilized to analyze the surface morphology and crystallographic structure respectively. To explore the mechanical properties e.g., yield stress, ultimate tensile strength and microhardness of irradiated brass, an universal tensile testing machine and Vickers microhardness tester were used. Scanning electron microscopy results revealed an irregular and randomly distributed sputter morphology for a lower ion fluence. With increasing ion fluence, the incoherently shaped structures were transformed into dendritic structures. Nano/micro sized craters and voids, along with the appearance of pits, were observed at the maximum ion fluence. From X-ray diffraction results, no new phases were observed to be formed in the brass upon irradiation. However, a change in the peak intensity and higher and lower angle shifting were observed, which represents the generation of ion-induced defects and stresses. Analyses confirmed modifications in the mechanical properties of irradiated brass. The yield stress, ultimate tensile strength and hardness initially decreased and then increased with increasing ion fluence. The changes in the mechanical properties of irradiated brass are well correlated with surface and crystallographic modifications and are attributed to the generation

  15. Effect of Thermally Reduced Graphene Oxide on Mechanical Properties of Woven Carbon Fiber/Epoxy Composite

    OpenAIRE

    Nitai Chandra Adak; Suman Chhetri; Naresh Chandra Murmu; Pranab Samanta; Tapas Kuila

    2018-01-01

    Thermally reduced graphene oxide (TRGO) was incorporated as a reinforcing filler in the epoxy resin to investigate the effect on the mechanical properties of carbon fiber (CF)/epoxy composites. At first, the epoxy matrix was modified by adding different wt % of TRGO from 0.05 to 0.4 wt % followed by the preparation of TRGO/CF/epoxy composites througha vacuum-assisted resin transfer molding process. The prepared TRGO was characterized by using Fourier transform infrared spectroscopy, Raman Spe...

  16. Effect of boron compounds on physical, mechanical, and fire properties of injection molded wood plastic composites

    Science.gov (United States)

    Nadir Ayrilmis; Turgay Akbulut; Turker Dundar; Robert H. White; Fatih Mengeloglu; Zeki Candan; Umit Buyuksari; Erkan Avci

    2011-01-01

    Physical, mechanical, and fire properties of the injection-molded wood flour/polypropylene composites (WPCs) incorporated with different levels of boron compounds, borax/boric acid (BX/BA) (0.5:0.5 wt %) and zinc borate (ZB) (4, 8, or 12 wt %) were investigated. The effect of the coupling agent loading (2, 4, or 6 wt %), maleic anhydride-grafted PP (MAPP), on the...

  17. Effect of thermo-mechanical treatments on creep and fatigue properties of 9% Cr martensitic steels

    International Nuclear Information System (INIS)

    Hollner, S.; Fournier, B.; Le Pendu, J.; Caes, C.; Tournie, I.; Pineau, A.

    2011-01-01

    In the framework of the development of Generation IV nuclear reactors and fusion nuclear reactors, materials with high mechanical properties up to 550 C are required. In service the materials will be subjected to high-temperature creep and cyclic loadings. 9-12%Cr martensitic steels are candidate materials for these applications; however, they show a pronounced cyclic softening effect under cyclic loadings. This softening effect is linked to the coarsening of the martensitic microstructure. In order to refine its microstructure and its precipitation state, the commercial P91 steel has been submitted to a thermo-mechanical treatment including warm-rolling at 600 C and a tempering stage at 700 C. Microstructural observations confirm that this thermo-mechanical treatment led to a finer martensite with smaller MX-type precipitates. This evolution has an effect on the high-temperature mechanical properties: the optimized P91 steel is 100 Hv harder than the as-received P91, and its yield strength is 430 MPa higher at 20 C and 220 MPa higher at 550 C. Its lifetime under creep (at 650 C under 120 MPa) is at least 14 times longer; and the fatigue test at 650 C under 0.7% strain shows a slightly slower cyclic softening effect for the optimized P91. (authors)

  18. Effect of bentonite modification on hardness and mechanical properties of natural rubber nanocomposites

    International Nuclear Information System (INIS)

    Santiago, Denise Ester O.; Pajarito, Bryan B.; Mangaccat, Winna Faye F.; Tigue, Maelyn Rose M.; Tipton, Monica T.

    2016-01-01

    The effect of sodium activation, ion-exchange with tertiary amine salt, surface treatment with non-ionic surfactant, and wet grinding of bentonite on hardness and mechanical properties of natural rubber nanocomposites (NRN) was studied using full factorial design of experiment. Results of X-ray diffraction (XRD) show increase in basal spacing d of bentonite due to modification, while attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) confirm the organic modification of bentonite. Analysis of variance (ANOVA) shows that the main effect of surface treatment increases the hardness and decreases the tensile modulus of the NRN. The surface treatment and wet grinding of bentonite decrease the tensile stresses at 100, 200 and 300% strain of NRN. Sodium activation and ion-exchange negatively affect the compressive properties, while surface treatment significantly improves the compressive properties of NRN.

  19. Effect of bentonite modification on hardness and mechanical properties of natural rubber nanocomposites

    Science.gov (United States)

    Santiago, Denise Ester O.; Pajarito, Bryan B.; Mangaccat, Winna Faye F.; Tigue, Maelyn Rose M.; Tipton, Monica T.

    2016-05-01

    The effect of sodium activation, ion-exchange with tertiary amine salt, surface treatment with non-ionic surfactant, and wet grinding of bentonite on hardness and mechanical properties of natural rubber nanocomposites (NRN) was studied using full factorial design of experiment. Results of X-ray diffraction (XRD) show increase in basal spacing d of bentonite due to modification, while attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) confirm the organic modification of bentonite. Analysis of variance (ANOVA) shows that the main effect of surface treatment increases the hardness and decreases the tensile modulus of the NRN. The surface treatment and wet grinding of bentonite decrease the tensile stresses at 100, 200 and 300% strain of NRN. Sodium activation and ion-exchange negatively affect the compressive properties, while surface treatment significantly improves the compressive properties of NRN.

  20. Effect of helium implantation on mechanical properties of EUROFER97 evaluated by nanoindentation

    International Nuclear Information System (INIS)

    Roldán, M.; Fernández, P.; Rams, J.; Jiménez-Rey, D.; Ortiz, C.J.; Vila, R.

    2014-01-01

    Helium effects on EUROFER97 mechanical properties were studied by means of nanoindentation. The steel was implanted with He ions in a stair-like profile configuration using energies from 2 to 15 MeV at room temperature. Firstly, a deep nanoindentation study was carried out on as-received state (normalized + tempered) in order to obtain a reliable properties database at the nanometric scale, including aspects such as indentation size effect. The nanoindentation hardness of tests on He implanted samples showed a hardness increase depending on the He concentration. The hardness increase follows the He implantation concentration profile with a good accuracy according to BCA calculations using MARLOWE code, considering the whole volume affected by the nanoindentation tests. The results obtained in this work shown that nanoindentation technique permits to assess any change of hardness properties due to ion implantation

  1. Effect of bentonite modification on hardness and mechanical properties of natural rubber nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Santiago, Denise Ester O. [Polymer Research Laboratory, Department of Chemical Engineering, University of the Philippines, Diliman, Quezon City 1101 Philippines (Philippines); Department of Chemical Engineering, University of the Philippines, Los Baños, College, Laguna 4031 Philippines (Philippines); Pajarito, Bryan B.; Mangaccat, Winna Faye F.; Tigue, Maelyn Rose M.; Tipton, Monica T. [Polymer Research Laboratory, Department of Chemical Engineering, University of the Philippines, Diliman, Quezon City 1101 Philippines (Philippines)

    2016-05-18

    The effect of sodium activation, ion-exchange with tertiary amine salt, surface treatment with non-ionic surfactant, and wet grinding of bentonite on hardness and mechanical properties of natural rubber nanocomposites (NRN) was studied using full factorial design of experiment. Results of X-ray diffraction (XRD) show increase in basal spacing d of bentonite due to modification, while attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) confirm the organic modification of bentonite. Analysis of variance (ANOVA) shows that the main effect of surface treatment increases the hardness and decreases the tensile modulus of the NRN. The surface treatment and wet grinding of bentonite decrease the tensile stresses at 100, 200 and 300% strain of NRN. Sodium activation and ion-exchange negatively affect the compressive properties, while surface treatment significantly improves the compressive properties of NRN.

  2. Effect of sensitization on the mechanical properties of type 304 L stainless steel

    International Nuclear Information System (INIS)

    Vargas Mendoza, L.F.

    1990-01-01

    The sensitization is a corrosion cause that it has studied broadly in the austenitic steels; however its relations don't knowed very well, into the sensitization and the steel's mechanical properties. Wherefore, the objectives of this work was to study the mechanical properties, in tension of austenitic steel with different levels of sensitization. The material utilized was a 304 L steel of standard composition AISI. The samples were sensitized at 450, 650 and 850 Centigrade degree, by short expositions, following by a temper in water. After this treatment, the tension test tubes were carried to rupture at low deformation velocity. The sensitization was evaluated by the method of Akashi EPR cyclic polarization. The sensitization distribution was analyzed by optical metallography in color and the fracture surface were studied by sweeping electronic microscopy. The distribution and length of the carbides were the factor that control the mechanic behavior of materials. At 450 Centigrade, the border of the grain its founded free of carbides, also for the longest times of exposition, but the particles are presented as fine precipitates in the grain interior, with this is increased the mechanical properties by the internal interactions of hardness or oldness types. At 650 Centigrade the frontiers show a dense distribution of fine carbides. These precipitates are interacting with the borders grain, increasing lightly the mechanical properties of steel. At 850 Centigrade, were formed discontinued carbides that not affect the mechanical behavior, but whether the fracture; the resistance is reduced and the ductility is increased although to impose the thermic effect of treatment. (Author)

  3. The effect of irradiation and hydration upon the mechanical properties of tendon

    International Nuclear Information System (INIS)

    Smith, C.W.; Kearney, J.N.

    1996-01-01

    Irradiation sterilization is in wide use among tissue banks, for both hard and soft tissue grafts. Irradiation of tendon can impair its mechanical properties. Following implantation of a tendon graft, re-vascularization and resorption processes reduce its mechanical performance. Tendon with severely impaired properties may not be suitable for use as a load-bearing graft, e.g. as anterior cruciate ligament replacement. An important factor determining the extent of the reduction of the mechanical performance is the condition of the tendon during irradiation, especially the presence of water. There has not yet been a study of the effects of both irradiation dose and hydration on tendon mechanical properties. This study measured the changes in tensile mechanical properties, including strength and stiffness, following γ irradiation doses of 15 kGy (1.5 MRad) and 25 kGy irradiated tendons was lower compared to fresh tendons, whereas the strength of the frozen irradiated tendons was very similar to that of the fresh. The tangent modulus of both of the freeze-dried irradiated groups were lower than the fresh tendons, as was the 15 kGy frozen group. The modulus of the 25 kGy frozen irradiated group was similar to the fresh. The general pattern of the results indicate that the two freeze-dried tendon groups were more affected than the frozen irradiated, and of the frozen irradiated groups the 25 kGy group was least affected. The results fit well with suggested mechanisms for the action of irradiation upon collagen; that intramolecular crosslinking and scission of the tropocollagen α chains occur when water is present, and α chain scission alone occurs when water is absent. Irradiation of tendons for use as grafts may produce minimal deleterious changes if the irradiation is performed while the tendon is frozen with water present. (Author)

  4. A review of the effect of vital teeth bleaching on the mechanical properties of tooth enamel.

    Science.gov (United States)

    Elfallah, Hunida M; Swain, Michael V

    2013-09-01

    Tooth whitening is considered the easiest and most cost-effective procedure for treating tooth discoloration. Contemporary bleaching agents contain hydrogen peroxide as the active ingredient. It is either applied directly or produced from its precursor, carbamide peroxide. A review of the published literature was undertaken to investigate the potential adverse effects of whitening products on dental enamel, with a focus on its mechanical properties and the influence of various parameters on study outcomes. There appear to be considerable differences in opinion as to whether changes in mechanical properties occur as a result of tooth whitening. However, the mechanical property findings of those studies appear to be related to the load applied during the indentation tests. Most studies which used loads higher than 500mN to determine enamel hardness showed no effect of bleaching, whereas those using lower loads were able to detect hardness reduction in the surface layer of enamel. In conclusion, bleaching reduces the hardness of the enamel surface of enamel, and that is more readily detected with instrumented low load testing systems. This hardness reduction may arise due to degradation or denaturation of enamel matrix proteins by the peroxide oxidation.

  5. Laser irradiation effects on the surface, structural and mechanical properties of Al-Cu alloy 2024

    Science.gov (United States)

    Yousaf, Daniel; Bashir, Shazia; Akram, Mahreen; kalsoom, Umm-i.-; Ali, Nisar

    2014-02-01

    Laser irradiation effects on surface, structural and mechanical properties of Al-Cu-Mg alloy (Al-Cu alloy 2024) have been investigated. The specimens were irradiated for various fluences ranging from 3.8 to 5.5 J/cm2 using an Excimer (KrF) laser (248 nm, 18 ns, 30 Hz) under vacuum environment. The surface and structural modifications of the irradiated targets have been investigated by scanning electron microscope (SEM) and X-ray diffractometer (XRD), respectively. SEM analysis reveals the formation of micro-sized craters along the growth of periodic surface structures (ripples) at their peripheries. The size of the craters initially increases and then decreases by increasing the laser fluence. XRD analysis shows an anomalous trend in the peak intensity and crystallite size of the specimen irradiated for various fluences. A universal tensile testing machine and Vickers microhardness tester were employed in order to investigate the mechanical properties of the irradiated targets. The changes in yield strength, ultimate tensile strength and microhardness were found to be anomalous with increasing laser fluences. The changes in the surface and structural properties of Al-Cu alloy 2024 after laser irradiation have been associated with the changes in mechanical properties.

  6. Effects of alkali treatment on the mechanical and thermal properties of Sansevieria trifasciata fiber

    Science.gov (United States)

    Mardiyati, Steven, Rizkiansyah, Raden Reza; Senoaji, A.; Suratman, R.

    2016-04-01

    In this study, Sansevieria trifasciata fibers were treated by NaOH with concentration 1%,3%, and 5wt% at 100°C for 2 hours. Chesson-Datta methods was used to determine the lignocellulose content of raw sansevieria fibers and to investigate effect of alkali treatment on lignin content of the fiber. Mechanical properties and thermal properties of treated and untreated fibers were measured by means of tensile testing machine and thermogravimetric analysis (TGA).The cellulose and lignin contents of raw sansevieria fiber obtained from Chesson-Datta method were 56% and 6% respectively. Mechanical testing of fibers showed the increase of tensile strength from 647 MPa for raw fibers to 902 MPa for 5wt% NaOH treated fibers. TGA result showed the alkali treatment increase the thermal resistance of fibers from 288°C for raw fibers to 307°C for 5% NaOH treated fiber. It was found that alkali treatment affect the mechanical properties and thermal properties of sansevieria fibers.

  7. Effect of maleic anhydride treatment on the mechanical properties of sansevieria fiber/vinyl ester composites

    Science.gov (United States)

    Pradipta, Rangga; Mardiyati, Steven, Purnomo, Ikhsan

    2017-03-01

    Sanseviera trifasciata commonly called mother-in-law tongue also known as snake plant is native to Indonesia, India and Africa. Sansevieria is a new fiber in composite research and has showed promising properties as reinforcement material in polymer matrix composites. Chemical treatment on reinforcing fiber is crucial to reduce hydrophilic tendency and thus improve compatibility with the matrix. In this study, effect of maleic anhydride as chemical treatment on the mechanical properties of Sansevieria fiber/vinyl ester composite was investigated. Sansevieria fibers were immersed by using NaOH 3% for two hours at 100°C and then treated by using maleic anhydrate for two hours at 120°C. Composites were prepared by solution casting with various volume fractions of fiber; 0%, 2.5%, 5%, 7.5% and 10%. Actual density, volume fraction of void and mechanical properties of composite were conducted according to ASTM standard testing methods D792, D3171 and D3039. It was found that mechanical properties of composites increased as volume fractions of fiber was increased. The highest tensile strength and modulus of elasticity of composites were 57.45 MPa and 3.47 GPa respectively, obtained from composites with volume fraction of fiber 10%.

  8. Effect of Processing Steps on the Mechanical Properties and Surface Appearance of 6063 Aluminium Extruded Products

    Science.gov (United States)

    Asensio-Lozano, Juan; Suárez-Peña, Beatriz; Vander Voort, George F.

    2014-01-01

    6063 aluminum anodized extrusions may exhibit a common surface defect known as streaking, characterized by the formation of narrow bands with a surface gloss different from the surrounding material. The origin of this banding lies in the differential surface topography produced after etching during the anodizing stage, shown to be connected to certain microstructural characteristics. The present study has attempted to determine the origin of these defects and measure the mechanical properties in these zones, properties which were either barely acceptable or did not meet the specification’s requirements. Quantitative metallography and mechanical testing, both tensile and microhardness, were used for materials assessment at the different steps of the process of manufacturing 6063 anodized extrusions. The results of this research show that nonequilibrium solidification rates during billet casting could lead to the formation of coarse eutectic Mg2Si particles which have a deleterious effect on both mechanical properties and surface appearance in the anodized condition. However, differences in the size and density of the coarse Mg2Si particles have been found to exist in the streak profile compared to the surrounding zones. The study revealed the importance of these particles in explaining the origin of the marginal or sub-marginal properties and anodizing surface defects found. PMID:28788673

  9. Effect of Processing Steps on the Mechanical Properties and Surface Appearance of 6063 Aluminium Extruded Products

    Directory of Open Access Journals (Sweden)

    Juan Asensio-Lozano

    2014-05-01

    Full Text Available 6063 aluminum anodized extrusions may exhibit a common surface defect known as streaking, characterized by the formation of narrow bands with a surface gloss different from the surrounding material. The origin of this banding lies in the differential surface topography produced after etching during the anodizing stage, shown to be connected to certain microstructural characteristics. The present study has attempted to determine the origin of these defects and measure the mechanical properties in these zones, properties which were either barely acceptable or did not meet the specification’s requirements. Quantitative metallography and mechanical testing, both tensile and microhardness, were used for materials assessment at the different steps of the process of manufacturing 6063 anodized extrusions. The results of this research show that nonequilibrium solidification rates during billet casting could lead to the formation of coarse eutectic Mg2Si particles which have a deleterious effect on both mechanical properties and surface appearance in the anodized condition. However, differences in the size and density of the coarse Mg2Si particles have been found to exist in the streak profile compared to the surrounding zones. The study revealed the importance of these particles in explaining the origin of the marginal or sub-marginal properties and anodizing surface defects found.

  10. Effects of mechanical properties of thermoplastic materials on the initial force of thermoplastic appliances.

    Science.gov (United States)

    Kohda, Naohisa; Iijima, Masahiro; Muguruma, Takeshi; Brantley, William A; Ahluwalia, Karamdeep S; Mizoguchi, Itaru

    2013-05-01

    To measure the forces delivered by thermoplastic appliances made from three materials and investigate effects of mechanical properties, material thickness, and amount of activation on orthodontic forces. Three thermoplastic materials, Duran (Scheu Dental), Erkodur (Erkodent Erich Kopp GmbH), and Hardcast (Scheu Dental), with two different thicknesses were selected. Values of elastic modulus and hardness were obtained from nanoindentation measurements at 28°C. A custom-fabricated system with a force sensor was employed to obtain measurements of in vitro force delivered by the thermoplastic appliances for 0.5-mm and 1.0-mm activation for bodily tooth movement. Experimental results were subjected to several statistical analyses. Hardcast had significantly lower elastic modulus and hardness than Duran and Erkodur, whose properties were not significantly different. Appliances fabricated from thicker material (0.75 mm or 0.8 mm) always produced significantly greater force than those fabricated from thinner material (0.4 mm or 0.5 mm). Appliances with 1.0-mm activation produced significantly lower force than those with 0.5-mm activation, except for 0.4-mm thick Hardcast appliances. A strong correlation was found between mechanical properties of the thermoplastic materials and force produced by the appliances. Orthodontic forces delivered by thermoplastic appliances depend on the material, thickness, and amount of activation. Mechanical properties of the polymers obtained by nanoindentation testing are predictive of force delivery by these appliances.

  11. Effect of the addition of mixture of plant components on the mechanical properties of wheat bread

    Science.gov (United States)

    Wójcik, Monika; Dziki, Dariusz; Biernacka, Beata; Różyło, Renata; Miś, Antoni; Hassoon, Waleed H.

    2017-10-01

    Instrumental methods of measuring the mechanical properties of bread can be used to determine changes in the properties of it during storage, as well as to determine the effect of various additives on the bread texture. The aim of this study was to investigate the effect of the mixture of plant components on the physical properties of wheat bread. In particular, the mechanical properties of the crumb and crust were studied. A sensory evaluation of the end product was also performed. The mixture of plant components included: carob fiber, milled grain red quinoa and black oat (1:2:2) - added at 0, 5, 10, 15, 20, 25 % - into wheat flour. The results showed that the increase of the addition of the proposed additive significantly increased the water absorption of flour mixtures. Moreover, the use of the mixture of plant components above 5% resulted in the increase of bread volume and decrease of crumb density. Furthermore, the addition of the mixture of plant components significantly affected the mechanical properties of bread crumb. The hardness of crumb also decreased as a result of the mixture of plant components addition. The highest cohesiveness was obtained for bread with 10% of additive and the lowest for bread with 25% of mixture of plant components. Most importantly, the enrichment of wheat flour with the mixture of plant components significantly reduced the crust failure force and crust failure work. The results of sensory evaluation showed that the addition of the mixture of plant components of up to 10% had little effect on bread quality.

  12. Effect of annealing temperature on the mechanical properties of Zircaloy-4 cladding

    International Nuclear Information System (INIS)

    Beauregard, R.J.; Clevinger, G.S.; Murty, K.L.

    1977-01-01

    The mechanical properties of Zircaloy cladding materials are sensitive to those fabrication variables which have an effect on the preferred crystallographic orientation or texture of the finished tube. The effect of one such variable, the final annealing temperature, on various mechanical properties is examined using tube reduced Zircaloy-4 fuel rod cladding annealed at temperatures from 905F to 1060F. This temperature range provides cladding with varying degrees of recrystallization including full recrystallization. The burst strength of the cladding at 650F decreased with the annealing temperature reaching a saturation value at approximately 1000F. The total circumferential elongation increased with the annealing temperature reaching a maximum at approximately 1000F and decreasing at higher temperatures. Hoop creep characteristics of Zircaloy cladding were studied as a function of the annealing temperature using closed-end internal pressurization tests at 750F and hoop stresses of 10, 15, 20 and 25 ksi. The effect of annealing temperature on the room temperature mechanical anisotropy parameters, R and P, was studied. The R-parameter was essentially independent of the annealing temperature while the P-parameter increased with annealing temperature. The mechanical anisotropy parameters were also studied as a function of the test temperature from ambient to approximately 800F using continuously monitored high precision extensometry. (Auth.)

  13. Effect of process parameters on microstructure and mechanical properties of friction stir welded joints: A review

    Science.gov (United States)

    Wanare, S. P.; Kalyankar, V. D.

    2018-04-01

    Friction stir welding is emerging as a promising technique for joining of lighter metal alloys due to its several advantages over conventional fusion welding processes such as low thermal distortion, good mechanical properties, fine weld joint microstructure, etc. This review article mainly focuses on analysis of microstructure and mechanical properties of friction stir welded joints. Various microstructure characterization techniques used by previous researchers such as optical microscopes, x-ray diffraction, electron probe microscope, transmission electron microscope, scanning electron microscopes with electron back scattered diffraction, electron dispersive microscopy, etc. are thoroughly overviewed and their results are discussed. The effects of friction stir welding process parameters such as tool rotational speed, welding speed, tool plunge depth, axial force, tool shoulder diameter to tool pin diameter ratio, tool geometry etc. on microstructure and mechanical properties of welded joints are studied and critical observations are noted down. The microstructure examination carried out by previous researchers on various zones of welded joints such as weld zone, heat affected zone and base metal are studied and critical remarks have been presented. Mechanical performances of friction stir welded joints based on tensile test, micro-hardness test, etc. are discussed. This article includes exhaustive literature review of standard research articles which may become ready information for subsequent researchers to establish their line of action.

  14. Contributions of chemical and mechanical surface properties and temperature effect on the adhesion at the nanoscale

    International Nuclear Information System (INIS)

    Awada, Houssein; Noel, Olivier; Hamieh, Tayssir; Kazzi, Yolla; Brogly, Maurice

    2011-01-01

    The atomic force microscope (AFM) is a powerful tool to investigate surface properties of model systems at the nanoscale. However, to get semi-quantitative and reproducible data with the AFM, it is necessary to establish a rigorous experimental procedure. In particular, a systematic calibration procedure of AFM measurements is necessary before producing reliable semi-quantitative data. In this paper, we study the contributions of the chemical and mechanical surface properties or the temperature influence on the adhesion energy at a local scale. To reach this objective, two types of model systems were considered. The first one is composed of rigid substrates (silicon wafers or AFM tips covered with gold) which were chemically modified by molecular self-assembling monolayers to display different surface properties (methyl and hydroxyl functional groups). The second one consists of model polymer networks (cross-linked polydimethylsiloxane) of variable mechanical properties. The comparison of the force curves obtained from the two model systems shows that the viscoelastic contributions dominate for the adhesion with polymer substrates, whereas, chemical contributions dominate for the rigid substrates. The temperature effect on the adhesion energy is also reported. Finally, we propose a relation for the adhesion energy at the nanoscale. This relation relates the energy measured during the separation of the contact to the three parameters: the surface properties of the polymer, the energy dissipated within the contact zone and the temperature.

  15. The Effects of Aluminium Hydroxide and Magnesium Hydroxide on the Mechanical Properties of Thermoplastic Polyurethane Materials

    Directory of Open Access Journals (Sweden)

    Erkin Akdoğan

    2015-12-01

    Full Text Available Thermoplastic polyurethane materials are widely used in automotive, clothing, electrical and electronics, medical, construction, machine industry due to excellent physical and chemical properties. Thermoplastic polyurethane materials combustion and resistance to high temperature characteristics are poor. Additives and fillers are added into the polyurethane matrix to improve those properties. Particularly adding these agents as a flame retardant are affect mechanical properties of polyurethane materials. Therefore, it is important to determinate the mechanical properties of these materials. In this study, 5% by weight of the thermoplastic polyurethane material, aluminium tri hydroxide (ATH, (Al2O3 3H2O and magnesium hydroxide (MgOH, (Mg(OH2 were added. Ammonium polyphosphate (APP as an intumescent flame retardant with inorganic flame retardants were added to increase the flame resistance of produced composite structure. Tensile test, tear test, hardness and Izod impact tests were made and compared of those produced composites. As a result of experiments the addition of ATH has lowered the tensile strength and tear strength contrast to this the addition of MgOH has improved those properties. Hardness and Izod impact test results were showed that both of the additives have no negative effect.

  16. Effects of joint alignment and type on mechanical properties of thermoplastic articulated ankle-foot orthosis.

    Science.gov (United States)

    Gao, Fan; Carlton, William; Kapp, Susan

    2011-06-01

    Articulated or hinged ankle-foot orthosis (AFO) allow more range of motion. However, quantitative investigation on articulated AFO is still sparse. The objective of the study was to quantitatively investigate effects of alignment and joint types on mechanical properties of the thermoplastic articulated AFO. Tamarack dorsiflexion assist flexure joints with three durometers (75, 85 and 95) and free motion joint were tested. The AFO joint was aligned with the center of the motor shaft (surrogate ankle joint), 10 mm superior, inferior, anterior and posterior with respect to the motor shaft center. The AFO was passively moved from 20° plantar flexion to 15° dorsiflexion at a speed of 10°/s using a motorized device. Mechanical properties including index of hysteresis, passive resistance torque and quasi-static stiffness (at neutral, 5°, 10° and 15° in plantar flexion) were quantified. Significant effects of joint types and joint alignment on the mechanical properties of an articulated thermoplastic AFO were revealed. Specifically, center alignment showed minimum resistance and stiffness while anterior and posterior alignment showed significantly higher resistance and stiffness. The dorsiflexion assist torques at neutral position ranged from 0.69 ± 0.09 to 1.88 ± 0.10 Nm. Anterior and posterior alignment should be avoided as much as possible. The current study suggested that anterior and posterior alignment be avoided as much as possible in clinical practice due to potential skin irritation and increase in stress around the ankle joint.

  17. The effect of clay incorporation on the mechanical properties of fluoroelastomer

    International Nuclear Information System (INIS)

    Zen, Heloisa Augusto; Oliveira, Jonathan Pereira de; Lugao, Ademar Benevolo

    2015-01-01

    In this work was studied the effect of clay incorporation in the mechanical properties of fluoroelastomer (FKM). The polymer matrix that was used is a compound of the commercial terpolymer of hexafluoropropylene, vinylidene fluoride and tetrafluoroethylene, with 70% of fluor content. This type of polymer is known for its resistance to high temperature and chemical products; it has low fuel permeation which allowing be used as sealant and especially as o-ring product. The incorporation of clay was carried to avoid excessive swelling and to observe the effect in the mechanical properties, for this application was used commercial clay, Cloisite® at 1 and 2% in weigh. The incorporation of clay into the FKM was carried out in a two roll cylinder. After that, the samples with and without clay loading were submitted to gamma radiation at 20 kGy in order to observe the changes in the polymer matrix. The characterization techniques used were: mechanical testes (stress - strain), rheometric properties and degree of swelling. After radiation process, was observed an increase in the swelling degree for the irradiated samples in relation to the pristine one. The incorporated samples with 1 and 2% of clay showed an increase in the elongation which can indicate a decrease in hardness of the polymer matrix. (author)

  18. The Effect of UVC Irradiation on the Mechanical Properties of Chitosan Membrane in Sterilization Process

    Science.gov (United States)

    Rupiasih, N. N.; Sumadiyasa, M.; Putra, I. K.

    2018-04-01

    The present study, we report about the effect of UVC irradiation on the mechanical properties of chitosan membrane in the sterilization process. The membrane used was chitosan membrane 2% which prepared by a casting method using chitosan as matrix and acetic acid 1% as a solvent. The UVC source used was germicidal ultraviolet (UVG) which widely used for sterilization purposes. Variation doses were done by the varying time of irradiation, e.g. 5 min, 15 min, 30 min, and 60 min. Those samples are named as S1, S2, S3, and S4, respectively. Chitosan membrane before irradiation namely S0 also used for comparative study. The effect of UVC irradiation on the mechanical properties of membranes has been examined by different techniques including FTIR, DMA, and the water uptake capability. The results showed that ultimate tensile strength (UTS) and moduli of elasticity (E) were increased by increasing the irradiation time. From FTIR analysis obtained that no new molecules were formed in irradiated membranes. The water uptakes capability of the membranes after irradiation was smaller compared with before irradiation, and among the irradiated membranes, the water uptake capabilities were increased by increasing the exposure time. These observations suggested that more care should be taken during the sterilization process and outdoor used of the membrane. The other side, the UVC irradiation can improve the mechanical properties of the membranes.

  19. Effect of tooth bleaching agents on protein content and mechanical properties of dental enamel.

    Science.gov (United States)

    Elfallah, Hunida M; Bertassoni, Luiz E; Charadram, Nattida; Rathsam, Catherine; Swain, Michael V

    2015-07-01

    This study investigated the effect of two bleaching agents, 16% carbamide peroxide (CP) and 35% hydrogen peroxide (HP), on the mechanical properties and protein content of human enamel from freshly extracted teeth. The protein components of control and treated enamel were extracted and examined on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Marked reduction of the protein matrix and random fragmentation of the enamel proteins after bleaching treatments was found. The mechanical properties were analyzed with Vickers indentations to characterize fracture toughness, and nanoindentation to establish enamel hardness, elastic modulus and creep deformation. Results indicate that the hardness and elastic modulus of enamel were significantly reduced after treatment with CP and HP. After bleaching, the creep deformation at maximum load increased and the recovery upon unloading reduced. Crack lengths of CP and HP treated enamel were increased, while fracture toughness decreased. Additionally, the microstructures of fractured and indented samples were examined with field emission gun scanning electron microscopy (FEG-SEM) showing distinct differences in the fracture surface morphology between pre- and post-bleached enamel. In conclusion, tooth bleaching agents can produce detrimental effects on the mechanical properties of enamel, possibly as a consequence of damaging or denaturing of its protein components. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  20. Effect of Trace Be and Sc Additions on the Mechanical Properties of A357 Alloys

    Directory of Open Access Journals (Sweden)

    Yu-Chih Tzeng

    2018-03-01

    Full Text Available The effect of the addition of Be and Sc on the microstructure and mechanical properties of A357 alloy were systematically investigated. The results show that the addition of small amounts of Be and Sc could change the acicular structure of iron-bearing intermetallic compounds to harmless compact Al-Fe-Si and Sc-Fe iron-bearing intermetallic compounds. Compact iron-bearing intermetallic compounds could improve fluidity, causing a reduction in interdendritic shrinkage during solidification. The addition of 0.05 wt % Be enhanced the quality index of the A357 alloy by 11% and increased the notch-yield ratio of fracture toughness by 4.5%. In contrast, the addition of 0.05 wt % Sc increased the quality index and the notch to yield ratio of fracture toughness up to 17% and 9%, respectively. Therefore, the microstructure and mechanical properties of the A357 alloy could be improved by substituting Be with Sc.

  1. THE EFFECT OF PLASTICIZER ON MECHANICAL PROPERTIES OF THE CEMENT PASTE WITH FINE GROUND RECYCLED CONCRETE

    Directory of Open Access Journals (Sweden)

    Jaromír Hrůza

    2017-11-01

    Full Text Available This article deals with the usage of recycled concrete, which arises from the demolition of concrete structures. The work is focused on the development of mechanical properties (Young's modulus, compressive and flexural strength depending amount of plasticizer in the mixture. In the experiment were prepared three sets of samples with different amounts of plasticizer (0, 0.5 and 1.0 wt. % of cement. Each pair always contained reference samples (only cement and 35 wt. % of fine ground recycled concrete. One of the main reasons for the use of finely ground recycled concrete was a certain substitution of cement in the mixture, which is the most expensive component. Development of Young's modulus was measured by the nondestructive method. The aim of the experiment was to determine the effect of plasticizer on the resulting physical and mechanical properties of cement pastes with fine ground recycled concrete.

  2. Effect of electron beam irradiation on mechanical properties of gelatin/Brazil nut shell fiber composites

    International Nuclear Information System (INIS)

    Inamura, Patricia Y.; Shimazaki, Kleber; Moura, Esperidiana Augusta Barretos de; Mastro, Nelida L. del; Colombo, Maria Aparecida; Rosa, Ricardo de

    2010-01-01

    The use of natural fiber as polymeric matrix reinforcement has attracted interest, as fibers are renewable, of low cost, biodegradable and possesses non-toxic properties. In the present paper, Brazil nuts (Bertholletia excelsa) shell fiber (10% w/w) were mixed with gelatin (25% w/w), glycerin as plasticizer and acrylamide as copolymer to investigate the resultant mechanical properties effects upon ionizing radiation. The samples were irradiated at 40 kGy using a Dynamitron electron beam accelerator, at room temperature in the presence of air. The results showed that samples of gelatin with 10% of Brazil nuts shell fiber and irradiated at 40 kGy presented promising results for mechanical performance. (author)

  3. Effect of heat conditions on the mechanical properties of boron nitride polycrystals

    International Nuclear Information System (INIS)

    Bochko, A.V.

    1986-01-01

    This paper examines the effect of various types of heat treatment on the mechanical and service properties of polycrystals of boron nitride. Quantitative phase analysis was carried out using the methods described when using a DRON-2.0 x-ray diffractometer. The mechanical characteristics were determined by the method of local loading using the standard nitride polycrystals in the initial state are quite high. On the basis of the results it may be concluded that the heat treatment conditions examined (annealing, hf heating, annealing and hf heating) lead to the same changes in the structural state as those taking place in thermal cycling thus causing the corresponding reduction of the level of the strength properties of the boron nitride polycrystals

  4. A Study of the Effect of Recycled Mix Glass on the Mechanical Properties of Green Concrete

    Directory of Open Access Journals (Sweden)

    Aseel B. Al-Zubaidi

    2017-12-01

    Full Text Available In this paper we utilized mixing of different types of recycled glass such as (neon glass, brown glass, and green glass that has high percentage of silicon dioxide (SiO2 with different concentrations. Utilization these landfall materials can be considered as keeping on resources. Different waste glasses used as a partial replacement of cement with different concentrations 11%, 13%, and 15% of cement weight for each type, and study the effect of it on the mechanical properties of concrete. After mixing, casting, and curing in water at (20±2°C for (7, 14, and 28 days, the mechanical properties showed that the compressive strength and flexural showed highest results at 13% from cement weight of neon glass, whereas splitting tensile strength showed the highest value at the same percentage, but from green glass.

  5. Effect of processing conditions on the mechanical properties of polypropylene/bentonite nano composites

    International Nuclear Information System (INIS)

    Alves, Tatianny S.; Cipriano, Pamela B.; Lira, Vanize F.; Canedo, Eduardo L.; Carvalho, Laura H. de

    2009-01-01

    This work dealt with the effect of processing conditions on the properties of polypropylene/bentonite compounds, using natural clay and an organoclay prepared with hexadecyl trimethyl ammonium bromide. Compounds with 1% clay were prepared by melt compounding in a single-screw extruder and in a counter-rotating twin-screw extruder, and characterized x-ray diffraction; tensile and impact mechanical tests. X ray diffraction results on clays and compounds show that the surfactant was incorporated within the clay galleries and that intercalated nano composites were obtained with the organoclay processed in either the single or the twin-screw extruder. The data also indicated that, without the addition of a compatibilizer, no significant variation of mechanical properties was observed for the composites processed in either extruder. (author)

  6. Effects of β treatments on microstructures and mechanical properties of TC4-DT titanium alloy

    International Nuclear Information System (INIS)

    Peng Xiaona; Guo Hongzhen; Wang Tao; Yao Zekun

    2012-01-01

    Highlights: ► Effects of β treatments on microstructures and mechanical properties of TC4-DT alloy were studied. ► The microstructure evolutions at each condition were analyzed. ► Influence of microstructures on tensile properties and fracture toughness were studied. ► Relationships among processing parameters–microstructures–properties were determined. - Abstract: β Processing (deformation in β phase field followed by heat treatment in α + β phase field) and β annealing (deformation in α + β phase field followed by annealing in β phase field) were carried out to research their influence on microstructures and mechanical properties including fracture toughness of TC4-DT titanium alloy. The tensile properties at room and high temperature as well as fracture toughness were tested for all the experiment conditions. The microstructure evolution and fracture surfaces were researched by optical microscope and scanning electronic microscope (SEM) and the microstructure features were measured by means of image analysis software. Results showed that the microstructures were lamellar in β processing and acicular Widmanstatten in β annealing respectively. Spheroidization of α lamellar was found in the microstructures of β processing. SEM observation showed that the fracture mechanism changed from transcrystalline in the β processing conditions to a mixture of intercrystalline and transcrystalline at the β annealing conditions. The tensile strength and plasticity did not change much under the β processing conditions. While at β annealing conditions, the strength and plasticity varied with the temperature in a reverse trend. The biggest fracture toughness was obtained at β annealing conditions. It was found that β annealing was preferable to β processing with regard to obtaining high fracture toughness and tensile properties with a little sacrifice of plasticity which does not affect its practice use.

  7. Effect of radiation on disinfection and mechanical properties of Korean traditional paper, Hanji

    International Nuclear Information System (INIS)

    Choi, Jong-il; Chung, Yong Jae; Kang, Dai Ill; Lee, Kyu Shik; Lee, Ju-Woon

    2012-01-01

    Fumigants, including methyl bromide and ethylene oxide, are generally used for the preservation of the Korean cultural heritage, especially paper products like letters and books. However, the use of fumigants is banned because of their harmful effects on humans and the environment. Gamma irradiation is being considered as an alternative for the sterilization of insects and fungi in organic products. Therefore, the purpose of this study was to investigate the sterilization effects of radiation and its effect on the mechanical properties of the Korean traditional paper—Hanji. Treatment doses of 9 kGy and 8 kGy of gamma irradiation inactivated 5 log units of Aspergillus niger and Bacillus cereus spores inoculated on Hanji, respectively. The gamma irradiations up to an absorbed dose of 50 kGy resulted in no significant changes in the tensile strength, bursting strength, and appearance of Hanji. These results confirmed that radiation treatment disinfects the Korean traditional paper efficiently without changing its properties and that this treatment could be used to prevent the damage of Korean ancient archives by molds and fungi. - Highlights: ► Radiation sensitivity of mold was tested on Korean traditional paper, Hanji. ► Mechanical properties of Hanji were measured to investigate the effect of irradiation. ► This result is useful to conserve the Korean cultural heritages made by Hanji with the radiation technology.

  8. Effect of Ionizing Beta Radiation on the Mechanical Properties of Poly(ethylene under Thermal Stress

    Directory of Open Access Journals (Sweden)

    Bednarik Martin

    2016-01-01

    Full Text Available It was found in this study, that ionizing beta radiation has a positive effect on the mechanical properties of poly(ethylene. In recent years, there have been increasing requirements for quality and cost effectiveness of manufactured products in all areas of industrial production. These requirements are best met with the polymeric materials, which have many advantages in comparison to traditional materials. The main advantages of polymer materials are especially in their ease of processability, availability, and price of the raw materials. Radiation crosslinking is one of the ways to give the conventional plastics mechanical, thermal, and chemical properties of expensive and highly resistant construction polymers. Several types of ionizing radiation are used for crosslinking of polymers. Each of them has special characteristics. Electron beta and photon gamma radiation are used the most frequently. The great advantage is that the crosslinking occurs after the manufacturing process at normal temperature and pressure. The main purpose of this paper has been to determine the effect of ionizing beta radiation on the tensile modulus, strength and elongation of low and high density polyethylene (LDPE and HDPE. These properties were examined in dependence on the dosage of the ionizing beta radiation (non-irradiated samples and those irradiated by dosage 99 kGy were compared and on the test temperature. Radiation cross-linking of LDPE and HDPE results in increased tensile strength and modulus, and decreased of elongation. The measured results indicate that ionizing beta radiation treatment is effective tool for improvement of mechanical properties of LDPE and HDPE under thermal stress.

  9. Effect of Al and Y2O3 on Mechanical Properties in Mechanically Alloyed Nanograin Ni-Based Alloys.

    Science.gov (United States)

    Kim, Chung Seok; Kim, Il-Ho

    2015-08-01

    The effects of aluminum and Y2O3 on the mechanical properties in nano grain Ni-based alloys have been investigated. The test specimens are prepared by mechanical alloying at an Ar atmosphere. The addition of Y2O3 and Al may cause an increase in the tensile strength at room temperature, 400 °C and 600 °C. However, it was confirmed that the increase of tensile strength at room temperature and 400 °C was predominantly caused by addition of Y2O3, while that at 600 °C was mainly due to addition of Al. These results can be attributed to the dispersion strengthening of Y2O3, preventing the formation of Cr2O3 and the change of fracture mode at 600 °C by the addition of Al.

  10. Effect of thermally reduced graphene oxide on dynamic mechanical properties of carbon fiber/epoxy composite

    Science.gov (United States)

    Adak, Nitai Chandra; Chhetri, Suman; Murmu, Naresh Chandra; Samanta, Pranab; Kuila, Tapas

    2018-03-01

    The Carbon fiber (CF)/epoxy composites are being used in the automotive and aerospace industries owing to their high specific mechanical strength to weight ratio compared to the other conventional metal and alloys. However, the low interfacial adhesion between fiber and polymer matrix results the inter-laminar fracture of the composites. Effects of different carbonaceous nanomaterials i.e., carbon nanotubes (CNT), graphene nanosheets (GNPs), graphene oxide (GO) etc. on the static mechanical properties of the composites were investigated in detail. Only a few works focused on the improvement of the dynamic mechanical of the CF/epoxy composites. Herein, the effect of thermally reduced grapheme oxide (TRGO) on the dynamic mechanical properties of the CF/epoxy composites was investigated. At first, GO was synthesized using modified Hummers method and then reduced the synthesized GO inside a vacuum oven at 800 °C for 5 min. The prepared TRGO was dispersed in the epoxy resin to modify the epoxy matrix. Then, a number of TRGO/CF/epoxy laminates were manufactured incorporating different wt% of TRGO by vacuum assisted resin transfer molding (VARTM) technique. The developed laminates were cured at room temperature for 24 h and then post cured at 120 °C for 2 h. The dynamic mechanical analyzer (DMA 8000 Perkin Elmer) was used to examine the dynamic mechanical properties of the TRGO/CF/epoxy composites according to ASTM D7028. The dimension of the specimen was 44×10×2.4 mm3 for the DMA test. This test was carried out under flexural loading mode (duel cantilever) at a frequency of 1 Hz and amplitude of 50 μm. The temperature was ramped from 30 to 200 °C with a heating rate of 5 °C min-1. The dynamic mechanical analysis of the 0.2 wt% TRGO incorporated CF/epoxy composites showed ~ 96% enhancement in storage modulus and ~ 12 °C increments in glass transition temperature (Tg) compared to the base CF/epoxy composites. The fiber-matrix interaction was studied by Cole

  11. Effects of plasma electrolytic oxidation process on the mechanical properties of additively manufactured porous biomaterials.

    Science.gov (United States)

    Gorgin Karaji, Zahra; Hedayati, Reza; Pouran, Behdad; Apachitei, Iulian; Zadpoor, Amir A

    2017-07-01

    Metallic porous biomaterials are recently attracting more attention thanks to the additive manufacturing techniques which help produce more complex structures as compared to conventional techniques. On the other hand, bio-functional surfaces on metallic biomaterials such as titanium and its alloys are necessary to enhance the biological interactions with the host tissue. This study discusses the effect of plasma electrolytic oxidation (PEO), as a surface modification technique to produce bio-functional layers, on the mechanical properties of additively manufactured Ti6Al4V scaffolds based on the cubic unit cell. For this purpose, the PEO process with two different oxidation times was applied on scaffolds with four different values of relative density. The effects of the PEO process were studied by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), optical microscopy as well as static and dynamic (fatigue) mechanical testing under compression. SEM results indicated pore formation on the surface of the scaffolds after oxidation with a thickness of 4.85±0.36μm of the oxide layer after 2min and 9.04±2.27μm after 5min oxidation (based on optical images). The static test results showed the high effect of relative density of porous structure on its mechanical properties. However, oxidation did not influence most of the mechanical properties such as maximum stress, yield stress, plateau stress, and energy absorption, although its effect on the elastic modulus was considerable. Under fatigue loading, none of the scaffolds failed even after 10 6 loading cycles at 70% of their yield stress. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Effects of fly ash fineness on the mechanical properties of concrete

    Indian Academy of Sciences (India)

    ash to have positive impact on mechanical properties of concrete. ... coarse ashes and their physical–chemical properties were evaluated. ... important factor affecting index of puzzolanic activity was fineness of the fly ash, not its chemical.

  13. Effect of Sc addition on microstructure and mechanical properties of 1460 alloy

    Directory of Open Access Journals (Sweden)

    Juan Ma

    2014-02-01

    Full Text Available The effect of minor addition of Sc on microstructure, age hardening behavior, tensile properties and fracture morphology of 1460 alloy have been studied. It is found that Sc content increase from 0.11 wt% to 0.22 wt% is favorable for grain refinement in as-cast alloy but results in a coarsening of Cu-rich particles. The alloy with 0.11 wt% Sc exhibits enhanced mechanical properties and age hardening effect. Transmission electron microscopy (TEM investigations on the alloy with 0.11 wt% Sc have suggested that a large amount of Al3(Sc, Zr particles precipitated at the earlier aging may inhibit recrystallization effectively.

  14. Effects of annealing on the corrosion behavior and mechanical properties of Ti-Al-V alloy

    International Nuclear Information System (INIS)

    Kim, T. K.; Choi, B. S.; Baek, J. H.; Choi, B. K.; Jeong, Y. H.; Lee, D. J.; Jang, M. H.; Jeong, Y. H.

    2002-01-01

    In order to determine the annealing condition after cold rolling, the effects of annealing on the corrosion behavior and mechanical properties of Ti-Al-V alloy were evaluated. The results of tensile tests at room temperature showed that the strengths and the ductility were almost independent of the annealing temperature. The results of hardness test also revealed that the hardness was independent of the annealing, However, the results of corrosion test in an ammoniated water of pH 9.98 at 360 .deg. C showed that the corrosion resistance depended on the annealing temperature, and the corrosion rate was accelerated with increasing annealing temperature. Hydrogen contents absorbed during the corrosion test of 120 days also increased with the annealing temperature. It may be attributed to the growth of α' precipitates by annealing. It is thus suggested that the lower annealing temperatures provide the better corrosion properties without degrading the tensile properties

  15. Effects of off-specification procedures on the mechanical properties of half-bead weld repairs

    International Nuclear Information System (INIS)

    Hobson, D.O.; Nanstad, R.K.

    1983-07-01

    We examined the effects of off-specification procedures on the mechanical properties of half-bead weld repairs. The name half-bead is derived from the specification that half the thickness of the initial weld layer be ground off before the second layer is deposited. In this study the heat-affected zones of a weldment made with both all and none of the first layer removed were tested for toughness, hardness, and microstructural differences, and the results were compared with the properties of a protypical half-bead repair made under ASME Boiler and Pressure Vessel Code, Sect. XI, guidelines. The results of this limited study showed no apparent justification for the requirement to grind off half the first layer in this type of weld repair. The graded electrode sizes used to make the welds probably had more to do with the weld properties than did the range of first-layer thicknesses used in this study

  16. Effects of Mechanical Properties on Tumor Invasion: Insights from a Cellular Model

    KAUST Repository

    Li, YZ

    2014-08-01

    Understanding the regulating mechanism of tumor invasion is of crucial importance for both fundamental cancer research and clinical applications. Previous in vivo experiments have shown that invasive cancer cells dissociate from the primary tumor and invade into the stroma, forming an irregular invasive morphology. Although cell movements involved in tumor invasion are ultimately driven by mechanical forces of cell-cell interactions and tumor-host interactions, how these mechanical properties affect tumor invasion is still poorly understood. In this study, we use a recently developed two-dimensional cellular model to study the effects of mechanical properties on tumor invasion. We study the effects of cell-cell adhesions as well as the degree of degradation and stiffness of extracellular matrix (ECM). Our simulation results show that cell-cell adhesion relationship must be satisfied for tumor invasion. Increased adhesion to ECM and decreased adhesion among tumor cells result in invasive tumor behaviors. When this invasive behavior occurs, ECM plays an important role for both tumor morphology and the shape of invasive cancer cells. Increased stiffness and stronger degree of degradation of ECM promote tumor invasion, generating more aggressive tumor invasive morphologies. It can also generate irregular shape of invasive cancer cells, protruding towards ECM. The capability of our model suggests it a useful tool to study tumor invasion and might be used to propose optimal treatment in clinical applications.

  17. The effect of thermal processing on microstructure and mechanical properties in a nickel-iron alloy

    Science.gov (United States)

    Yang, Ling

    The correlation between processing conditions, resulted microstructure and mechanical properties is of interest in the field of metallurgy for centuries. In this work, we investigated the effect of thermal processing parameters on microstructure, and key mechanical properties to turbine rotor design: tensile yield strength and crack growth resistance, for a nickel-iron based superalloy Inconel 706. The first step of the designing of experiments is to find parameter ranges for thermal processing. Physical metallurgy on superalloys was combined with finite element analysis to estimate variations in thermal histories for a large Alloy 706 forging, and the results were adopted for designing of experiments. Through the systematic study, correlation was found between the processing parameters and the microstructure. Five different types of grain boundaries were identified by optical metallography, fractography, and transmission electron microscopy, and they were found to be associated with eta precipitation at the grain boundaries. Proportions of types of boundaries, eta size, spacing and angle respect to the grain boundary were found to be dependent on processing parameters. Differences in grain interior precipitates were also identified, and correlated with processing conditions. Further, a strong correlation between microstructure and mechanical properties was identified. The grain boundary precipitates affect the time dependent crack propagation resistance, and different types of boundaries have different levels of resistance. Grain interior precipitates were correlated with tensile yield strength. It was also found that there is a strong environmental effect on time dependent crack propagation resistance, and the sensitivity to environmental damage is microstructure dependent. The microstructure with eta decorated on grain boundaries by controlled processing parameters is more resistant to environmental damage through oxygen embrittlement than material without eta

  18. Effect of Post-weld Heat Treatment on the Mechanical Properties of Supermartensitic Stainless Steel Deposit

    Science.gov (United States)

    Zappa, Sebastián; Svoboda, Hernán; Surian, Estela

    2017-02-01

    Supermartensitic stainless steels have good weldability and adequate tensile property, toughness and corrosion resistance. They have been developed as an alternative technology, mainly for oil and gas industries. The final properties of a supermartensitic stainless steel deposit depend on its chemical composition and microstructure: martensite, tempered martensite, ferrite, retained austenite and carbides and/or nitrides. In these steels, the post-weld heat treatments (PWHTs) are usually double tempering ones, to ensure both complete tempering of martensite and high austenite content, to increase toughness and decrease hardness. The aim of this work was to study the effect of post-weld heat treatments (solution treatment with single and double tempering) on the mechanical properties of a supermartensitic stainless steel deposit. An all-weld metal test coupon was welded according to standard ANSI/AWS A5.22-95 using a GMAW supermartensitic stainless steel metal cored wire, under gas shielding. PWHTs were carried out varying the temperature of the first tempering treatment with and without a second tempering one, after solution treatment. All-weld metal chemical composition analysis, metallurgical characterization, hardness and tensile property measurements and Charpy-V tests were carried out. There are several factors which can be affected by the PWHTs, among them austenite content is a significant one. Different austenite contents (0-42%) were found. Microhardness, tensile property and toughness were affected with up to 15% of austenite content, by martensite tempering and carbide precipitation. The second tempering treatment seemed not to have had an important effect on the mechanical properties measured in this work.

  19. Chirality and grain boundary effects on indentation mechanical properties of graphene coated on nickel foil

    Science.gov (United States)

    Yan, Yuping; Lv, Jiajiang; Liu, Sheng

    2018-04-01

    We investigate chirality and grain boundary (GB) effects on indentation mechanical properties of graphene coated on nickel foil using molecular dynamics simulations. The models of graphene with different chirality angles, different numbers of layers and tilt GBs were established. It was found that the chirality angle of few-layer graphene had a significant effect on the load bearing capacity of graphene/nickel systems, and this turns out to be more significant when the number of layers is greater than one. The enhancement to the contact stiffness, elastic capacity and the load bearing capacity of graphene with tilt GBs was lower than that of pristine graphene.

  20. New graphic classification and theory of H effects on the mechanical properties of metal systems

    International Nuclear Information System (INIS)

    Fidelle, J.P.

    1988-09-01

    A simple use of the theory of sets allows an accurate yet concise classification of hydrogen effects on metals mechanical properties, generally embrittlements and/or corrosions or other effects, mostly noxious or sometimes favorable but limited. Gas bubbles role is more general than reported. Metals affected by (a) dissol-ved (-ing) H or (b) solid hydrides able to be generated by direct hydrogen/solid metals reactions are, like H itself, ''A'' metals of Mendeleiev's table; ''B'' metals are not affected, or only under extreme conditions, unless alloyed with A metals

  1. Effect of cyclic electron irradiation on mechanical properties of austenite steel

    International Nuclear Information System (INIS)

    Tsepelev, A.B.; Sadykhov, S.I.O.; Chernov, A.I.; Sevost'yanov, M.A.

    2006-01-01

    To check the supposition on the possibility of radiation-stimulated process enhancement under cyclic irradiation conditions an experimental investigation is carried out to elucidate the effect of the mode of irradiation (continuous or cyclic) on mechanical properties of chromium-manganese austenitic stainless steel type 10Kh12G20V. The effect of some radiation hardening is observed under cyclic irradiation, however, the data obtained cannot be considered as good evidence for the validity of proposed model of dynamic preference if the scatter in experimental data is taken into account [ru

  2. Effects of CTR irradiation on the mechanical properties of structural materials

    International Nuclear Information System (INIS)

    Wiffen, F.W.

    1976-11-01

    Mechanical properties of CTR structural materials are important in determining the reliability and economics of fusion power. Furthermore, these properties are significantly affected by the high neutron flux experienced by components in the regions near the plasma of the fusion reactor. In general, irradiation hardens the material and leads to a reduction in ductility. An exception to this is in some complex engineering alloys where either hardening or softening can be observed depending on the alloy and the irradiation conditions. Regardless of this restriction, irradiation usually leads to a reduction in ductility. Available tensile data examined in this paper show that significant ductility reduction can be found for irradiation conditions typical of CTR operation. Consideration of these effects show that extensive work will be needed to fully establish the in-service properties of CTR structures. This information will be used by designers to develop conditions and design philosophies adapted to avoid the most deleterious conditions and minimize stresses on structures on reactor design. The information will also be used as input to alloy development programs with goals of producing materials more resistant to property degradation during irradiation. It is clear that a great deal of additional work will be required both to understand the effect of CTR irradiation on properties and to develop optimal alloys for this application

  3. The effect of temperature and drawing ratio on the mechanical properties of polypropylene monofilaments

    Science.gov (United States)

    Taheri, Hesam; Nóbrega, João Miguel; Samyn, Pieter; Covas, José Antonio

    2014-05-01

    In this work, the simultaneous effect of both temperature and drawing ratio during processing of polypropylene monofilaments has been investigated. The basis of this work specifically aims at emphasizing the conditions of temperature and drawing ratio applied in the cooling bath, in order to find out under which conditions the named parameters can be applied in a processing line under continuous extrusion. The effects of temperature are studied for a constant total drawing ratio to analyze the influences on mechanical properties and structural differences of the final polypropylene monofilament. The quenched monofilaments were drawn around an adjustable guide assembly in the quench bath and first drawing stage, imparting thermal and mechanical treatments to the filaments. In the heating stage, monofilaments are affected to high-speed draw rolls while passing through the oven. As such, the best conditions to produce a polypropylene monofilament with high tenacity strength were determined. Results of this study show that the monofilament properties are significantly affected by temperature in the cooling zone. The nature of the first drawing had a significant effect on the end properties and monofilaments with modulus of 637 MPa have finally been manufactured. We have also proposed a new hypothesis, which is termed "gap nucleation" and determine this phenomenon in the gap between die and cooling bath.

  4. The effect of metal ion implantation on the surface mechanical properties of Mylar (PET)

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, W; Sood, D K [Royal Melbourne Inst. of Tech., VIC (Australia); Yao, X; Brown, I G [California Univ., Berkeley, CA (United States). Lawrence Berkeley Lab.

    1994-12-31

    Ion implantation of polymers leads to the formation of new carbonaceous materials, the revolution during implantation of various species consists of (1) ion beam induced damage: chain scission, crosslinking, molecular emission of volatile elements and compounds, stoichiometric change in the surface layer of pristine polymers; and (2) chemical effect between ion and target materials: microalloying and precipitation. Literature regarding ion implanted polymers shows that the reorganisation of the carbon network after implantation can dramatically modify several properties of pristine polymers solubility, molecular weight, and electrical, optical and mechanical properties. However, ion implantation of polymers is actually a very complex interaction which depends on not only ion species, implantation condition, but also polymer type and specific structure. In this paper the effect of Ag or Ti ions implantation on surface mechanical properties of PET (polyethylenne terephthalate) polymer is reported. There was a clear deterioration in wear resistance after implantation of both Ag and Ti ions. It is suggested that the increment of wear after implantation may result from not only ion damage but also chemical effect between ion and target material. 3 refs., 1 tab., 2 figs.

  5. The effect of metal ion implantation on the surface mechanical properties of Mylar (PET)

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, W.; Sood, D.K. [Royal Melbourne Inst. of Tech., VIC (Australia); Yao, X.; Brown, I.G. [California Univ., Berkeley, CA (United States). Lawrence Berkeley Lab.

    1993-12-31

    Ion implantation of polymers leads to the formation of new carbonaceous materials, the revolution during implantation of various species consists of (1) ion beam induced damage: chain scission, crosslinking, molecular emission of volatile elements and compounds, stoichiometric change in the surface layer of pristine polymers; and (2) chemical effect between ion and target materials: microalloying and precipitation. Literature regarding ion implanted polymers shows that the reorganisation of the carbon network after implantation can dramatically modify several properties of pristine polymers solubility, molecular weight, and electrical, optical and mechanical properties. However, ion implantation of polymers is actually a very complex interaction which depends on not only ion species, implantation condition, but also polymer type and specific structure. In this paper the effect of Ag or Ti ions implantation on surface mechanical properties of PET (polyethylenne terephthalate) polymer is reported. There was a clear deterioration in wear resistance after implantation of both Ag and Ti ions. It is suggested that the increment of wear after implantation may result from not only ion damage but also chemical effect between ion and target material. 3 refs., 1 tab., 2 figs.

  6. Effect of mechanical stress on the magnetic properties of amorphous Fe-B ribbons

    International Nuclear Information System (INIS)

    Kecer, J.; Novak, L.

    2011-01-01

    From this point of view, we have dealt with the effect of mechanical stress in this work. It is one of the variables, together with an external magnetic field and temperature, in which it can be expected a significant impact on changes in magnetic properties of amorphous ferromagnets prepared by rapid quenching of the melt. Internal tensions, significantly affecting the magnetic parameters, are introduced into the material already under preparation. Although the rate of internal stresses in amorphous tape is high, we can see significant changes in the measured magnetic parameters induced by mechanical stresses. By applying mechanical stress on amorphous sample Fe 84 B 16 , is highlighted the impact of internal stresses in the direction of stress, which induces the direction of axis of easy magnetising and it results in filling the hysteresis loop to the J axis, coercivity values decreasing by half, constant of magnetoelastic anisotropy decreasing by half and change in the value of magnetostriction. (authors)

  7. Effect of gamma irradiation on the structural, mechanical and optical properties of polytetrafluoroethylene sheet

    Science.gov (United States)

    Mohammadian-Kohol, M.; Asgari, M.; Shakur, H. R.

    2018-04-01

    In this study, the effects of gamma radiation on the chemical structure, mechanical and optical properties of polytetrafluoroethylene (PTFE) sheet were investigated with various doses up to 12 kGy. The chemical changes in the structure were studied by FTIR spectroscopy. Also, effects of radiation on the different mechanical parameters such as Young's modulus, toughness, strain, and stress were studied at the maximum tolerable force and the fracture points. Furthermore, changing the various optical parameters such as absorption coefficient, Urbach energy, optical band gaps, refractive index, optical dispersion parameters and plasma resonance frequency were studied by UV-visible spectroscopy. Formation of a band at 1594 cm-1, which was belonged to double carbon bonds, indicated that chain-scission was occurred at 12 kGy gamma irradiation dose. As well, the mechanical results showed an increase in the elastic behavior of PTFE sheets and a decrease in the plastic behavior of it with absorbed dose increasing. Moreover, the results showed that gamma irradiation can effectively change the various optical properties of PTFE sheets due to different phenomena such as degradation of the main chains, occurring chain-scission, formation of free radicals and cross-linking in the polymer structure.

  8. Effect of annealing temperature on the mechanical properties of zircaloy-4 cladding

    International Nuclear Information System (INIS)

    Beauregard, R.J.; Clevinger, G.S.; Murty, K.L.

    1977-01-01

    The mechanical properties of zircaloy cladding materials are sensitive to those fabrication variables which have an effect on the preferred crystallographic orientation or texture of the finished tube. The effect of one such variable, the final annealing temperature, on various mechanical properties is examined using tube reduced zircaloy-4 fuel rod cladding annealed at temperatures from 905F to 1060F. This temperature range provides cladding with varying degrees of recrystallization including full recrystallization. Hoop creep characteristics of zircaloy cladding were studied as a function of the annealing temperature using closed-end internal pressurization tests at 750F and hoop stresses of 10, 15, 20 and 25 ksi. The critical annealing temperature at which a minimum creep strain occurs decreases as the applied stress increases. An additional test at 700F and 30 ksi hoop stress was conducted to demonstrate that the critical annealing temperature is essentially independent of the test temperature. Plausible explanations based on differing substructures developed in cold-worked stress-relieved material are forwarded. The effect of annealing temperature on the room temperature mechanical anisotropy parameters, R and P, was studied. R-parameters were determined from in situ transverse strain gage measurements in uniaxial tensile tests. P-parameters were calculated from uniaxial test data (R and yield stress) and hoop yield stress determined in biaxial, closed-end internal pressurization tests

  9. Effects of solution treatment on mechanical properties and corrosion resistance of 4A duplex stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Panpan; Wang, Aiqin; Wang, Wenyan [Henan Univ. of Science and Technology, Luoyang (China). School of Material Science and Engineering; Xie, Jingpei [Henan Univ. of Science and Technology, Luoyang (China). Collaborative Innovation Center of Nonferrous Metals

    2018-02-15

    In this study, 4A duplex stainless steels were prepared via remelting in an intermediate frequency furnace and subsequently solution treated at different temperatures. The effects of solution treatment on the mechanical properties and corrosion resistance of 4A duplex stainless steel were investigated. Microstructures were characterized via optical microscopy and scanning electron microscopy. The mechanical properties were evaluated via hardness test, tensile test, and impact test experiments. The point corrosion resistance was studied via chemical immersion and potentiodynamic anodic polarization. The results showed that with increasing solution temperature in the range of 1223 - 1423 K, the tensile strength and hardness first decreased and then increased, and minimum values were obtained at 1323 K. The σ phase precipitated at the boundaries of the α/γ phases in samples solution treated at 1223 K, decreasing both impact energy and pitting potential of the experimental steels. When experimental steels were solution treated at 1373 K for 2 h, a suitable volume fraction of α/γ was uniformly distributed throughout the microstructure, and the steels exhibited optimal mechanical properties and pitting corrosion resistance.

  10. Effects of varied porosity on the physic-mechanical properties of sintered ceramic from Ifon clay

    Directory of Open Access Journals (Sweden)

    Fatai Olufemi ARAMIDE

    2017-12-01

    Full Text Available The effects of saw dust admixture on the physic-mechanical properties of sintered clay bonded carbonized palm kernel shell ceramic was investigated. Composite mixtures of powdered carbonized palm kernel shell and clay from Ifon deposit were produced using equal amount of clay and carbonized palm kernel shell. These were then mixed with varied amount of saw dust (0%, 5% and 10% in a ball mill for 6 hours. From this standard sample specimens were produced using uniaxial compression after mixing each mixture with 10% moisture of clay contents. The compressed samples were sintered at 9500C and soaked for one hour. The sintered samples were characterized for various physic-mechanical properties using state of the art equipment’s. The fired samples were also characterized using ultra-high-resolution field emission scanning electron microscope (UHR-FEGSEM equipped with energy dispersive spectroscopy (EDX. It was observed that the apparent porosity and water absorption of the clay bonded carbonized palm kernel shell ceramic increased with increased amount of saw dust admixture, cold crushing strength, Young’ modulus of elasticity and absorbed energy of the sample reduced with increased amount of saw dust admixture. It was concluded that the sample with 0% saw dust admixture is judged to possess optimum physic-mechanical properties.

  11. Incorporation of multiwalled carbon nanotubes to acrylic based bone cements: effects on mechanical and thermal properties.

    Science.gov (United States)

    Ormsby, Ross; McNally, Tony; Mitchell, Christina; Dunne, Nicholas

    2010-02-01

    Polymethyl methacrylate (PMMA) bone cement-multiwalled carbon nanotube (MWCNT) nanocomposites with a weight loading of 0.1% were prepared using 3 different methods of MWCNT incorporation. The mechanical and thermal properties of the resultant nanocomposite cements were characterised in accordance with the international standard for acrylic resin cements. The mechanical properties of the resultant nanocomposite cements were influenced by the type of MWCNT and method of incorporation used. The exothermic polymerisation reaction for the PMMA bone cement was significantly reduced when thermally conductive functionalised MWCNTs were added. This reduction in exotherm translated in a decrease in thermal necrosis index value of the respective nanocomposite cements, which potentially could reduce the hyperthermia experienced in vivo. The morphology and degree of dispersion of the MWCNTs in the PMMA matrix at different scales were analysed using scanning electron microscopy. Improvements in mechanical properties were attributed to the MWCNTs arresting/retarding crack propagation through the cement by providing a bridging effect into the wake of the crack, normal to the direction of crack growth. MWCNT agglomerations were evident within the cement microstructure, the degree of these agglomerations was dependent on the method used to incorporate the MWCNTs into the cement. Copyright 2009. Published by Elsevier Ltd.

  12. Effect of Quenching Media on Mechanical Properties of Medium Carbon Steel 1030

    Directory of Open Access Journals (Sweden)

    Khansaa Dawood Salman

    2018-01-01

    Full Text Available This investigation aims to study the effect of quenching media (water, oil, Poly Vinyl Chloride PVC on mechanical properties of 1030 steel. The applications of this steel include machinery parts where strength and hardness are requisites. The steel is heated to about 950  and soaked for 1hr in electrical furnace and then quenched in different quenching medium such as water, oil and poly vinyl chloride. After heat treatment by quenching, the specimens are tempered at 250  for 1hr and then cooling in air. The mechanical properties of the specimens are determined by using universal tensile testing machine for tensile test, Vickers hardness apparatus for hardness testing, measuring the grain size of the phases and examine the microstructure of the specimens before and after heat-treatment. The results of this work showed that improving the mechanical properties of medium carbon 1030 steel, which is quenching by water gives the preferred results as the following: Quenching by water leads to increase σy, σu.t.s, K and hardness, but at the same time quenching by water leads to decrease E and n. Also the quenching by water and followed by tempering leads to improve the microstructure and decreasing (refining of the grain size of ferrite and pearlite phases of the steel used in this work.

  13. Effect of simulated mechanical recycling processes on the structure and properties of poly(lactic acid).

    Science.gov (United States)

    Beltrán, F R; Lorenzo, V; Acosta, J; de la Orden, M U; Martínez Urreaga, J

    2018-06-15

    The aim of this work is to study the effects of different simulated mechanical recycling processes on the structure and properties of PLA. A commercial grade of PLA was melt compounded and compression molded, then subjected to two different recycling processes. The first recycling process consisted of an accelerated ageing and a second melt processing step, while the other recycling process included an accelerated ageing, a demanding washing process and a second melt processing step. The intrinsic viscosity measurements indicate that both recycling processes produce a degradation in PLA, which is more pronounced in the sample subjected to the washing process. DSC results suggest an increase in the mobility of the polymer chains in the recycled materials; however the degree of crystallinity of PLA seems unchanged. The optical, mechanical and gas barrier properties of PLA do not seem to be largely affected by the degradation suffered during the different recycling processes. These results suggest that, despite the degradation of PLA, the impact of the different simulated mechanical recycling processes on the final properties is limited. Thus, the potential use of recycled PLA in packaging applications is not jeopardized. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Effect of zirconia content and powder processing mechanical properties of gelcasted ZTA composite

    International Nuclear Information System (INIS)

    Khoshkalam, M.; Faghihi-Sani, M.A.; Nojoomi, A.

    2013-01-01

    Addition of fine zirconia particles in the alumina matrix in order to produce ZTA composite is a well-known method for improving the mechanical properties of alumina ceramics such as flexural strength and fracture toughness. Increasing homogeneity and reducing alumina grain size are two key factors for achieving proper mechanical properties in this ceramic matrix composite. In this work two batches of ZTA powder precursor were prepared through mixing of alumina and zirconia by ball milling and in situ synthesis of ZTA composite via solution combustion method. The bending strength testing samples were fabricated through gel-casting process. The effects of different powder processing methods as well as zirconia contents on microstructural homogeneity and mechanical properties of ZTA composites were investigated. The samples produced by solution combustion synthesized powder yielded higher homogeneity, finer microstructure and higher flexural strength. Results showed an upswing in the fracture toughness for the synthesized samples even up to 20 vol% zirconia, while the mixed samples depicted optimum fracture toughness in 10 vol% zirconia content. (author)

  15. Effect of surface treatment of carbon nanotubes on mechanical properties of cement composite

    Directory of Open Access Journals (Sweden)

    KONDAKOV Alexander Igorevich

    2014-08-01

    Full Text Available The aim of the paper is to explore the influence of the carbon nanotubes functionalized by oxygen groups on the physical and mechanical properties of cement composites. Advantages and disadvantages of the main methods for the homogeneous distribution of carbon nanotubes (CNTs in solution are discussed. A method for covalent functionalization of CNTs is described. An acid-base titration and dispersion analysis of solutions containing functionalized carbon nanotubes (f-CNTs was performed. The research data made it possible to propose new technology of preparation of modified concrete. The results of the work can be used for designing of the additives commonly used in the construction industry, as well as for further studies of the effects of CNTs on the physical and mechanical and structural properties of building materials. Efficient modification of cement composite with f-CNTs was achieved at the concentration of f-CNTs ranging from 0.0004% to 0.0008% by weight of the binder. The observed increase of the concrete mechanical properties is explained by the fact that the CNTs act as nucleation centers for the cement hydration products.

  16. Effect of two-step aging on the mechanical properties of AA2219 DC cast alloy

    Energy Technology Data Exchange (ETDEWEB)

    Elgallad, E.M., E-mail: eelgalla@uqac.ca; Zhang, Z.; Chen, X.-G.

    2015-02-11

    With its combination of high specific strength, good machinability and excellent weldability, AA2219 direct chill (DC) cast alloy has become a new category of materials for manufacturing large molds for the plastics and automotive industries. The effect of two-step aging on the microstructural evolution and mechanical properties of AA2219 DC cast alloy was investigated. The precipitate microstructure was characterized under different heat treatment conditions using differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). The poor mechanical properties of the air-quenched alloy were attributed to the presence of quench-induced coarse θ′ and θ precipitates, which had very limited contribution to the precipitation hardening during the aging treatment. The two-step aging treatment of the air-quenched AA2219 alloy involved the precipitation of GP zones in the first step followed by their transformation into fine θ″ strengthening precipitates in the second step, which considerably improved the mechanical properties. After undergoing 120 °C/36 h+190 °C/8 h two-step aging, the hardness, YS and UTS of the air-quenched alloy were increased by 27%, 46% and 15%, respectively, compared with 190 °C/8 h one-step aging.

  17. Effect of Extraction Process and Surface Treatment on the mechanical properties in Pineapple Leaf Fibre

    Directory of Open Access Journals (Sweden)

    Ariffin Azrie

    2017-01-01

    Full Text Available Pineapple Leaf Fibre (PALF is a one of the natural fibre that has high potential in the industry. Natural fibres have become the main alternative source in the modern world industry. The objective of this study is to observe the effect chemical treatment using Sodium Hydroxide (NaOH solution on the physical and mechanical properties of pineapple leaf fibre. Different concentration of NaOH solution (2%, 4%, 6%, 8% and different treatment time (1 hour, 3 hour and 5 hour are used for the experiment. The tensile test was conducted to obtain the mechanical properties such as tensile strength, Yong modulus, (E and elongation at break. From the results obtained, NaOH concentration of 6% and five-hour treatment time that was used for treatment showed the higher physical and mechanical properties values. Furthermore, morphology analysis also shows the surface of the fibre at 6% NaOH after five-hour of treatment was in the better condition with good bonding arrangement of the fibre.

  18. Pectin- and gelatin-based film: effect of gamma irradiation on the mechanical properties and biodegradation

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Cheorun; Kang, Hojin; Lee, Na Young; Kwon, Joong Ho; Byun, Myung Woo E-mail: mwbyun@kaeri.re.kr

    2005-04-01

    Agricultural by-products, pectin and gelatin, were used to prepare a biodegradable film. The film casting solution including the pectin and gelatin was irradiated at 0, 10, 20, and 30 kGy to investigate the irradiation effect on the mechanical properties of the film. The tensile strength of the 10 kGy-irradiated film was the highest among the treatments but the elongation at break, water vapour permeability, and swelling ratio were the lowest. Hunter color L*- and a*-values decreased but the b*-value increased as the irradiation dose increased. The total organic carbon content produced from the Paenibacillus polymyxa and Pseudomonas aeruginosa also showed that the film of 10 kGy-irradiated was lower than those of 0, 20, and 30 kGy-irradiated films. In conclusion, irradiation of the film casting solution at 10 kGy increased the mechanical properties of the pectin and gelatin based film. To manufacture the film by agricultural by-products, however, the irradiation dose of the film casting solution should be determined to achieve better mechanical properties.

  19. The effect warming time of mechanical properties and structural phase aluminum alloy nickel

    International Nuclear Information System (INIS)

    Husna Al Hasa, M.; Anwar Muchsin

    2011-01-01

    Ferrous aluminum alloys as fuel cladding will experience the process of heat treatment above the recrystallization temperature. Temperature and time of heat treatment will affect the nature of the metal. Heating time allows will affect change in mechanical properties, thermal and structure of the metal phase. This study aims to determine the effect of time of heat treatment on mechanical properties and phase metal alloys. Testing the mechanical properties of materials, especially violence done by the method of Vickers. Observation of microstructural changes made by metallographic-optical and phase structure were analyzed Based on the x-ray diffraction patterns Elemental analysis phase alloy compounds made by EDS-SEM. Test results show the nature of violence AlFeNiMg alloy by heating at 500°C with a warm-up time 1 hour, 2 hours and 3 hours respectively decreased range 94.4 HV, 87.6 HV and 85.1 HV. The nature of violence AlFeNi alloy showed a decrease in line with the longer heating time. Metallographic-optical observations show the microstructural changes with increasing heating time. Microstructure shows the longer the heating time trend equi axial shaped grain structure of growing and the results showed a trend analyst diffraction pattern formation and phase θ α phase (FeAl3) in the alloy. (author)

  20. Effects of temperature on mechanical properties of SU-8 photoresist material

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Soon Wan; Park, Seung Bae [State University of New York, New York (United States)

    2013-09-15

    A representative fabrication processing of SU-8 photoresist, Ultraviolet (UV) lithography is usually composed of spin coat, soft bake, UV exposure, post exposure bake (PEB), development and optional hard bake, etc. The exposed region of SU-8 is crosslinked during the PEB process and its physical properties highly depend on UV exposure and PEB condition. This work was initiated to investigate if thermal baking after fabrication can affect the mechanical properties of SU-8 photoresist material because SU-8 is trying to be used as a structural material for MEMS operated at high temperature. Since a temperature of 95 .deg. C is normally recommended for PEB process, elevated temperatures up to 200 .deg. C were considered for the optional hard bake process. The viscoelastic material properties were measured by dynamic mechanical analyses (DMA). Also, pulling tests were performed to obtain Young's modulus and Poisson's ratio as a function of strain rate in a wide temperature range. From this study, the effects of temperature on the elastic and viscoelastic material properties of SU-8 were obtained.

  1. Effects of temperature on mechanical properties of SU-8 photoresist material

    International Nuclear Information System (INIS)

    Chung, Soon Wan; Park, Seung Bae

    2013-01-01

    A representative fabrication processing of SU-8 photoresist, Ultraviolet (UV) lithography is usually composed of spin coat, soft bake, UV exposure, post exposure bake (PEB), development and optional hard bake, etc. The exposed region of SU-8 is crosslinked during the PEB process and its physical properties highly depend on UV exposure and PEB condition. This work was initiated to investigate if thermal baking after fabrication can affect the mechanical properties of SU-8 photoresist material because SU-8 is trying to be used as a structural material for MEMS operated at high temperature. Since a temperature of 95 .deg. C is normally recommended for PEB process, elevated temperatures up to 200 .deg. C were considered for the optional hard bake process. The viscoelastic material properties were measured by dynamic mechanical analyses (DMA). Also, pulling tests were performed to obtain Young's modulus and Poisson's ratio as a function of strain rate in a wide temperature range. From this study, the effects of temperature on the elastic and viscoelastic material properties of SU-8 were obtained.

  2. Effect of boron on the microstructure and mechanical properties of carbidic austempered ductile iron

    International Nuclear Information System (INIS)

    Peng Yuncheng; Jin Huijin; Liu Jinhai; Li Guolu

    2011-01-01

    Highlights: → Boron are applied to carbidic austempered ductile iron (CADI). → Boron microalloying CADI is a new high hardenability of wear-resistant cast iron. → Addition of boron to CADI significantly improves hardenability. → Effect of boron on the CADI grinding ball were investigated. → Optimum property is obtained when boron content at 0.03 wt%. - Abstract: Carbidic austempered ductile iron (CADI) castings provide a unique combination of high hardness and toughness coupled with superior wear resistance properties, but their hardenability restricts their range of applications. The purpose of this study was to investigate the influence of boron on the microstructure and mechanical properties of CADI. The experimental results indicate that the CADI comprises graphite nodules, which are dispersive boron-carbides that are distributed in the form of strips, and the matrix is a typical ausferritic matrix. Microscopic amounts of boron can improve the hardenability of CADI, but higher boron content reduces the hardenability and toughness of CADI. The results are discussed in the context of the influence of boron content on the microstructure and mechanical properties of grinding balls.

  3. Thermal Mechanical Processing Effects on Microstructure Evolution and Mechanical Properties of the Sintered Ti-22Al-25Nb Alloy.

    Science.gov (United States)

    Wang, Yuanxin; Lu, Zhen; Zhang, Kaifeng; Zhang, Dalin

    2016-03-11

    This work illustrates the effect of thermal mechanical processing parameters on the microstructure and mechanical properties of the Ti-22Al-25Nb alloy prepared by reactive sintering with element powders, consisting of O, B2 and Ti₃Al phases. Tensile and plane strain fracture toughness tests were carried out at room temperature to understand the mechanical behavior of the alloys and its correlation with the microstructural features characterized by scanning and transmission electron microscopy. The results show that the increased tensile strength (from 340 to 500 MPa) and elongation (from 3.6% to 4.2%) is due to the presence of lamellar O/B2 colony and needle-like O phase in B2 matrix in the as-processed Ti-22Al-25Nb alloys, as compared to the coarse lath O adjacent to B2 in the sintered alloys. Changes in morphologies of O phase improve the fracture toughness ( K IC ) of the sintered alloys from 7 to 15 MPa·m -1/2 . Additionally, the fracture mechanism shifts from cleavage fracture in the as-sintered alloys to quasi-cleavage fracture in the as-processed alloys.

  4. Effect of V or Zr addition on the mechanical properties of the mechanically alloyed Al-8wt%Ti alloys

    International Nuclear Information System (INIS)

    Moon, I.H.; Lee, J.H.; Lee, K.M.; Kim, Y.D.

    1995-01-01

    Mechanical alloying (MA) of Al-Ti alloy, being a solid state process, offers the unique advantage of producing homogeneous and fine dispersions of thermally stable Al 3 Ti phase, where the formation of the fine Al 3 Ti phase by the other method is restricted from the thermodynamic viewpoint. The MA Al-Ti alloys show substantially higher strength than the conventional Al alloys at the elevated temperature due to the presence of Al 3 Ti as well as Al 4 C 3 and Al 2 O 3 , of which the last two phases were introduced during MA process. The addition of V or Zr to Al-Ti alloy was known to decrease the lattice mismatch between the intermetallic compound and the aluminum matrix, and such decrease in lattice mismatching can influence positively the high temperature mechanical strength of the MA Al-Ti by increasing the resistance to dispersoid coarsening at the elevated temperature. In the present study, therefore, the mechanical behavior of the MA Al-Ti-V and Al-Ti-Zr alloys were investigated in order to evaluate the effect of V or Zr addition on the mechanical properties of the MA Al-8Ti alloy at high temperature

  5. Effects of Nanofillers on the Thermo-Mechanical Properties and Chemical Resistivity of Epoxy Nanocomposites.

    Science.gov (United States)

    Atchudan, Raji; Pandurangan, Arumugam; Joo, Jin

    2015-06-01

    MWCNTs was synthesized using Ni-Cr/MgO by CVD method and were purified. The purified MWCNT was used as a filler material for the fabrication of epoxy nanocomposites. The epoxy nanocomposites with different amount (wt% = 0.5, 1.0, 2.0, 3.0, 4.0 and 5.0) of nanofillers (CB, SiO2 and MWCNTs) were prepared by casting method. The effects of nanofillers on the properties of neat epoxy matrix were well studied. The thermal properties of nanocomposites were studied using DSC, TGA and flame retardant, and also the mechanical properties such as tensile strength, flexural strength, compressive strength, impact strength, determination of hardness and chemical resistance were studied extensively. Based on the experiment's results, 2 wt% MWCNTs loading in epoxy resin showed the highest improvement in tensile strength, as compared to neat epoxy and to other epoxy systems (CB/epoxy, SiO2/epoxy). Improvements in tensile strength, glass transition temperature and decomposition temperature were observed by the addition of MWCNTs. The mechanical properties of the epoxy nanocomposites were improved due to the interfacial bonding between the MWCNTs and epoxy resin. Strain hardening behavior was higher for MWCNT/epoxy nanocomposites compared with CB/epoxy and SiO2/epoxy nanocomposites. The investigation of thermal and mechanical properties reveals that the incorporation of MWCNTs into the epoxy nanocomposites increases its thermal stability to a great extent. Discrete increase of glass transition temperature of nanocomposites is linearly dependent on MWCNTs content. Due to strong interfacial bonding between MWCNTs and epoxy resin, the chemical resistivity of MWCNT/epoxy nanocomposites is superior to neat epoxy and other epoxy systems.

  6. Effect of training and rest on respiratory mechanical properties in racing sled dogs.

    Science.gov (United States)

    Davis, Michael; Williamson, Katherine; McKenzie, Erica; Royer, Christopher; Payton, Mark; Nelson, Stuart

    2005-02-01

    Racing Alaskan sled dogs develop exercise-induced airway inflammation, similar to that reported for elite human athletes participating in cold-weather sports. These human athletes also have airway hyperresponsiveness, but airway function in sled dogs has not been measured. To compare respiratory mechanical properties in trained, rested Alaskan sled dogs with typical laboratory hounds, and to determine whether subsequent training alters respiratory mechanical properties. Nineteen healthy adult Alaskan sled dogs were compared with five healthy adult mixed-breed laboratory hounds. All dogs were rested for at least 4 months before examination. Respiratory mechanical properties were measured while the dogs were anesthetized and ventilated with a piston ventilator. The mean respiratory resistance and compliance measurements for 20 consecutive breaths were used as baseline values immediately before measurement of respiratory reactivity. Respiratory reactivity was the mean of 20 consecutive breaths immediately after the administration of aerosol histamine, expressed as the percentage change in prehistamine measurements. After the initial examinations, the sled dogs were divided into exercised and controls. Exercised dogs were trained for competitive endurance racing. Both groups were examined after 2 and 4 months of training. Alaskan sled dogs had greater respiratory compliance reactivity to histamine (77.47 +/- 8.58% baseline) compared with laboratory dogs (87.60 +/- 9.22% baseline). There was no effect of training on respiratory mechanical properties detected in racing sled dogs. Racing Alaskan sled dogs have airway dysfunction similar to "ski asthma" that persists despite having 4 months of rest. These findings suggest that repeated exercise in cold conditions can lead to airway disease that does not readily resolve with cessation of exercise.

  7. Effect of Cu on the microstructural and mechanical properties of as-cast ductile iron

    International Nuclear Information System (INIS)

    Tiwari, Siddhartha; Das, J.; Ray, K.K.; Kumar, Hemant; Bhaduri, A.

    2012-01-01

    The application of ductile cast iron in the heavy engineering components like, cask for the storage and transportation of radioactive materials, demands high strength with improved fracture toughness in as cast condition. The mechanical properties and fracture toughness of as-cast ductile iron (DI) is directly related to its structure property which can be controlled by proper inoculation, alloying elements and cooling rate during solidification. The aim of the present investigation is to study the effect of varying amount of Cu (0.07%, 0.11%, and 0.16%) with 1% Ni in the microstructural development of as-cast ductile iron with emphasis on its mechanical properties and fracture toughness. Three different ductile irons have been prepared using induction furnace in batches of 300 kg following industrial practice. Microstructural features (amount of phases, morphology, size and count of graphite nodules) and mechanical properties (tensile strength and hardness) of prepared DI were determined using standard methods. Dynamic fracture toughness was measured using instrumented Charpy impact test on pre-cracked specimens following the standard ISO-FDIS-26843. Additionally, fracture surfaces of broken tensile and pre-cracked specimens were observed by SEM to study the micro-mechanism of fracture. The pearlite fraction and the nodule count are found to increase with increasing amount of copper in ferritic-pearlitic matrix. The hardness and strength values are found to increase with increasing amount of pearlite whereas fracture toughness decreases. Fractographs of broken specimens exhibited decohesion of graphite, crack propagation from graphite interface and transgranular fracture of ferrite. (author)

  8. Effect of mechanical alloying and compaction parameters on the mechanical properties and microstructure of EUROFER 97 ODS steel

    International Nuclear Information System (INIS)

    Ramar, A.; Oksiuta, Z.; Baluc, N.; Schaeublin, R.

    2006-01-01

    Oxide dispersion strengthened (ODS) ferritic / martensitic (F/M) steels appear to be promising candidates for the future fusion reactor. Their inherent properties, good thermal conductivity, swelling resistance and low radiation damage accumulation, deriving from the base material EUROFER 97, are further enhanced by the presence of the fine dispersion of oxide particles. They would allow in principle for a higher operating temperature of the fusion reactor, which improves its thermal efficiency. In effect, their strength remains higher than the base material with increasing temperature. Their creep properties are also improved relatively to the base material. It is the pinning of dislocations at dispersed oxide particles that helps to improve the high temperature mechanical properties. EUROFER97 is a reduced activation F/M steel, whose chemical composition is 8.9 wt. % Cr, 1.1 wt. % W, 0.47 wt. % Mn, 0.2 wt. % V, 0.14 wt. % Ta and 0.11 wt. % C and Fe for the balance. A new ODS F/M steel based on EUROFER 97 is developed with the strengthening material as Y 2 O 3 maintained at 0.3wt% based on our past experience. The ODS powder is produced by a different powder metallurgy route. The Eurofer 97 atomized powder with particle sizes around 45 μm is ball milled in argon atmosphere in a planetary ball mill together with Yttria particles with sizes about 10 to 30 nm. The milled powders are now canned in a steel container. They are degassed at 450 o C for 3 hours under a vacuum of 10-5 mbar. The canned sample is sealed in vacuum and finally compacted by hot isostatic pressing (HIP) in argon atmosphere under a pressure of 180 MPa at 1000 o C for 1 hour. Electron microscopy and X-ray diffraction observations are done at regular intervals during ball milling to identify changes in the particle and crystallite size and in particular with the solubility of Yttria in the matrix. Further, The microstructure and mechanical properties of final compacted material is assessed. The

  9. Inhibitory effect on Streptococcus mutans and mechanical properties of the chitosan containing composite resin

    Directory of Open Access Journals (Sweden)

    Ji-Sun Kim

    2013-02-01

    Full Text Available Objectives This study evaluated the antibacterial effect and mechanical properties of composite resins (LCR, MCR, HCR incorporating chitosan with three different molecular weights (L, Low; M, Medium; H, High. Materials and Methods Streptococcus (S. mutans 100 mL and each chitosan powder were inoculated in sterilized 10 mL Brain-Heart Infusion (BHI solution, and was centrifuged for 12 hr. Absorbance of the supernatent was measured at OD660 to estimate the antibacterial activities of chitosan. After S. mutans was inoculated in the disc shaped chitosan-containing composite resins, the disc was cleansed with BHI and diluted with serial dilution method. S. mutans was spread on Mitis-salivarius bacitracin agar. After then, colony forming unit (CFU was measured to verify the inhibitory effect on S. mutans biofilm. To ascertain the effect on the mechanical properties of composite resin, 3-point bending and Vickers hardness tests were done after 1 and 3 wk water storage, respectively. Using 2-way analysis of variance (ANOVA and Scheffe test, statistical analysis was done with 95% significance level. Results All chitosan powder showed inhibition effect against S. mutans. CFU number in chitosan-containing composite resins was smaller than that of control resin without chitosan. The chitosan containing composite resins did not show any significant difference in flexural strength and Vickers hardness in comparison with the control resin. However, the composite resin, MCR showed a slightly decreased flexural strength and the maximum load than those of control and the other composite resins HCR and LCR. Conclusions LCR and HCR would be recommended as a feasible antibacterial restorative due to its antibacterial nature and mechanical properties.

  10. The Effects of Carbon Nanotubes on the Mechanical and Wear Properties of AZ31 Alloy

    Directory of Open Access Journals (Sweden)

    Mingyang Zhou

    2017-12-01

    Full Text Available Carbon nanotube (CNT-reinforced AZ31 matrix nanocomposites were successfully fabricated using a powder metallurgy method followed by hot extrusion. The influence of CNTs on microstructures, mechanical properties, and wear properties were systematically investigated by optical microscope (OM, scanning electron microscope (SEM, X-ray diffraction (XRD, hardness test, tensile test, and wear test. The results revealed that the nanocomposites showed a slightly smaller grain size compared with the matrix and uniform distribution that CNTs could achieve at proper content. As a result, the addition of CNTs could weaken basal plane texture. However, the yield strength and ultimate tensile strength of the composites were enhanced as the amount of CNTs increased up to 2.0 wt. %, reaching maximum values of 241 MPa (+28.2% and 297 MPa (+6.1%, respectively. The load transfer mechanism, Orowan mechanism, and thermal mismatch mechanism played important roles in the enhancement of the yield strength, and several classical models were employed to predict the theoretical values. The effect of CNT content on the friction coefficient and weight loss of the nanocomposites was also studied. The relationships between the amount of CNTs, the friction coefficient, and weight loss could be described by the exponential decay model and the Boltzmann model, respectively.

  11. Effect of epoxidised soybean oil loading as plasticiser on physical, mechanical and thermal properties of polyvinylchloride

    Science.gov (United States)

    Rahmah, M.; Nurazzi, N. Mohd; Farah Nordyana, A. R.; Syed Anas, S. M.

    2017-07-01

    The aim of this paper is to study the effect of epoxidised soybean oil (ESO) as an alternative plasticizer on physical, mechanical and thermal properties of plasticised polyvinyl chloride (PPVC). Samples were prepared using 10, 20, 30 and 40% by weight percent of ESO. The samples were characterized for density, water absorption, tensile, hardness and thermal properties. The addition of ESO as plasticizer in PVC had caused significant effect on the physical and mechanical properties of PPVC. Increasing of ESO loading had resulted in decreased density, tensile strength, tensile modulus but increased in elongation at break and shore hardness. From water absorption study, it was observed that the all the samples reached the plateau absorption at days 8 to 10 with absorption percentages of between 1.8 to 2%. In general the crystallinity of PPVC maintained between 10 to 13% with increase in ESO loading while the melting point ( Tm) is slightly decreased about 3 to 6°C. In this study, ESO which acts as plasticiser were found to result in lower glass transition temperature (Tg). The enhancements of super cooling with higher ESO loading were found to increase the crystallization temperature, promoting crystallisation and act as nucleating agent.

  12. Various effects of antidepressant drugs on bone microarchitectecture, mechanical properties and bone remodeling

    International Nuclear Information System (INIS)

    Bonnet, N.; Bernard, P.; Beaupied, H; Bizot, J.C.; Trovero, F.; Courteix, D.; Benhamou, C.L.

    2007-01-01

    The aim of this study was to evaluate the effects of various drugs which present antidepressant properties: selective serotonin-reuptake inhibitors (SSRIs, fluoxetine), serotonin and noradrenaline-reuptake inhibitors (Desipramine) and phosphodiesterase inhibitors (PDE, rolipram and tofisopam) on bone microarchitecture and biomechanical properties. Twelve female mice were studied per group starting at an age of 10 weeks. During 4 weeks, they received subcutaneously either placebo or 20 mg kg -1 day -1 of desipramine, fluoxetine or 10 mg kg -1 day -1 of rolipram or tofisopam. Serum Osteocalcin and CTx were evaluated by ELISA. Bone microarchitecture of the distal femur was characterized by X-ray microCT (Skyscan1072). Mechanical properties were assessed by three-point bending test (Instron 4501) and antidepressant efficacy by forced swimming and open field tests. Fluoxetine displayed lower TbTh (- 6.1%, p -1 , 6431 ± 1182 MPa) than in placebo (101 ± 9 N mm -1 , 8441 ± 1180 MPa). Bone markers indicated a significantly higher bone formation in tofisopam (+ 8.6%) and a lower in fluoxetine (- 56.1%) compared to placebo. These data suggest deleterious effects for SSRIs, both on trabecular and cortical bone and a positive effect of PDE inhibitors on trabecular bone. Furthermore tofisopam anabolic effect in terms of bone markers, suggests a potential therapeutic effect of the PDE inhibitors on bone

  13. The effect of mechanical drawing on optical and structural properties of nylon 6 fibres

    Science.gov (United States)

    El-Bakary, M. A.

    2007-09-01

    The Pluta polarizing double-refracting interference microscope was attached to a mechanical drawing device to study the effect of cold drawing on the optical and structural properties of nylon 6 fibres. The microscope was used in its two positions for determining the refractive indices and birefringence of fibres. Different applied stresses and strain rates were obtained using the mechanical-drawing device. The effect of the applied stresses on the optical and physical parameters was investigated. The resulting optical parameters were utilized to investigate the polarizability per unit volume, the optical orientation factor, the orientation angle and the average work per chain. The refractive index and birefringence profiles were measured. Relationships between the average work per chain and optical parameters at different strains rates were determined. An empirical formula was deduced for these fibres. Micro-interferograms are given for illustration.

  14. Effects of erbium modification on the microstructure and mechanical properties of A356 aluminum alloys

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Z.M., E-mail: shizm@imut.edu.cn; Wang, Q.; Zhao, G.; Zhang, R.Y.

    2015-02-25

    The effects of erbium (Er) modification on the microstructure and mechanical properties of A356 aluminum alloys were investigated using optical microscope, X-ray diffraction, scanning electronic microscope and mechanical testing. Experimental results show that additions of Er refined the α-Al grains and eutectic Si phases in its as-cast state; the addition of 0.3 wt% of Er has the best effects on them. The Fe-containing Al{sub 3}Er phases were introduced by the modifications; by a T6 treatment, the eutectic Si phases were further sphereodized; the large Al{sub 3}Er and β-Al{sub 5}FeSi phases were changed into fine particles and short rods; which enhanced the hardness of the alloys. The highest strength and elongation were obtained for the 0.3 wt% of Er-modified and T6-treated A356 alloy.

  15. Iron particle and anisotropic effects on mechanical properties of magneto-sensitive elastomers

    Science.gov (United States)

    Kumar, Vineet; Lee, Dong-Joo

    2017-11-01

    Rubber specimens were prepared by mixing micron-sized iron particles dispersed in room-temperature-vulcanized (RTV) silicone rubber by solution mixing. The possible correlations of the particle volume, size, and distribution with the mechanical properties of the specimens were examined. An isotropic mechanical test shows that at 60 phr, the elastic modulus was 3.29 MPa (electrolyte), 2.92 MPa (carbonyl), and 2.61 MPa (hybrid). The anisotropic effect was examined by curing the specimen under magnetic fields of 0.5-2.0 T at 90° relative to the applied strain. The measurements show anisotropic effects of 11% (carbonyl), 9% (electrolyte), and 6% (hybrid) at 40 phr and 1 T. At 80 phr, the polymer-filler compatibility factor (c-factor) was estimated using the Pythagorean theorem as 0.53 (regular) and 0.73 (anisotropic studies). The improved features could be useful in applications such as controlled damping, vibrational absorption, or automotive bushings.

  16. Effect of copper addition on mechanical properties, corrosion resistance and antibacterial property of 316L stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Xi, Tong [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Shahzad, M. Babar [Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Xu, Dake [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Sun, Ziqing; Zhao, Jinlong [Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Yang, Chunguang, E-mail: cgyang@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Qi, Min [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Yang, Ke, E-mail: kyang@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China)

    2017-02-01

    The effects of addition of different Cu content (0, 2.5 and 3.5 wt%) on mechanical properties, corrosion resistance and antibacterial performance of 316L austenitic stainless steel (SS) after solution and aging treatment were investigated by mechanical test, transmission electron microscope (TEM), X-ray diffraction (XRD), electrochemical corrosion, X-ray photoelectron spectroscopy (XPS) and antibacterial test. The results showed that the Cu addition and heat treatment had no obvious influence on the microstructure with complete austenite features. The yield strength (YS) after solution treatment was almost similar, whereas the aging treatment obviously increased the YS due to formation of tiny Cu-rich precipitates. The pitting and protective potential of the solution treated Cu-bearing 316L SS in 0.9 wt% NaCl solution increased with increasing Cu content, while gradually declined after aging, owing to the high density Cu-rich precipitation. The antibacterial test proved that higher Cu content and aging were two compulsory processes to exert good antibacterial performance. The XPS results further indicated that aging enhanced the Cu enrichment in passive film, which could effectively stimulate the Cu ions release from the surface of passive film. - Highlights: • Higher Cu addition and aging guaranteed an excellent antibacterial property. • The Cu addition and heat treatment had no obvious influence on the microstructure. • The lower corrosion resistance for aging was attributed to Cu-rich precipitates.

  17. Effects of heat treatment on the mechanical properties of kenaf fiber

    Energy Technology Data Exchange (ETDEWEB)

    Carada, Paulo Teodoro D. L. [Master’s student in the Graduate School of Science and Engineering, Mechanical Engineering, Doshisha University, 1-3 Tatara Miyakodani, Kyotanabe City, Kyoto Prefecture, 610-0394 (Japan); Fujii, Toru; Okubo, Kazuya [Professor in the Faculty of Science and Engineering, Department of Mechanical and Systems Engineering, Doshisha University, 1-3 Tatara Miyakodani, Kyotanabe City, Kyoto Prefecture, 610-0394 (Japan)

    2016-05-18

    Natural fibers are utilized in various ways. One specific application of it, is in the field natural fiber composite (NFC). Considerable amount of researches are conducted in this field due to rising concerns in the harmful effects of synthetic materials to the environment. Additionally, these researches are done in order to overcome the drawbacks which limit the wide use of natural fiber. A way to improve NFC is to look into the reinforcing component (natural fiber). Treatments, which are classified as mechanical or chemical in nature, can be done in order to improve the performance of the natural fiber. The aim of this study is to assess the effects of heat treatment in the mechanical properties of kenaf fiber. In addition, the response of mechanical properties after exposure to high moisture environment of heat-treated kenaf fibers was observed. Heat treatment was done for one hour with the following heating temperatures: 140, 160, 180, and 200 °C. X-ray diffraction analysis was done to calculate the crystallinity index of kenaf fibers after heat treatment. The results showed that increase in tensile strength can be attained when kenaf fibers are heat treated at 140 °C. However, the tensile modulus showed inconsistency with respect to heat treatment temperature. The computed crystallinity index of the fiber matched the tensile strength observed in non-treated and heat-treated kenaf fibers. The results obtained in this study can be used for applications where heat treatment on kenaf fibers is needed.

  18. Effects of Stress Concentration on the Mechanical Properties of Carbon Fiber Reinforced Plastic

    Directory of Open Access Journals (Sweden)

    Ryo Naito

    2017-03-01

    Full Text Available Mechanical properties of conventional CFRP plates with small holes were investigated systematically. Those artificial holes are considered to be rivet connection between CFRP and other materials. The machining holes were employed with different number (n=0-5 and different mode, e.g., parallel (Sample A, 45 degree (Sample B and perpendicular (Sample C against the loading direction. To understand the mechanical properties of the CFRP plates clearly, tensile tests and failure analysis were conducted experimentally. Excellent mechanical properties were obtained for Sample A, compared to the other ones. This is due to the different size of the cross-section area in the specimen. With increasing the number of rivet hole, the mechanical properties were lineally decreasing. Such mechanical properties were analyzed by direct observation using a high speed camera, i.e., in-situ measurement of deformation during the tensile loading was carried

  19. Effect of nitrogen and fluorine on mechanical properties and bioactivity in two series of bioactive glasses.

    Science.gov (United States)

    Bachar, Ahmed; Mercier, Cyrille; Tricoteaux, Arnaud; Hampshire, Stuart; Leriche, Anne; Follet, Claudine

    2013-07-01

    Bioactive glasses are able to bond to bone through formation of carbonated hydroxyapatite in body fluids, and fluoride-releasing bioactive glasses are of interest for both orthopaedic and, in particular, dental applications for caries inhibition. However, because of their poor strength their use is restricted to non-load-bearing applications. In order to increase their mechanical properties, doping with nitrogen has been performed on two series of bioactive glasses: series (I) was a "bioglass" composition (without P2O5) within the quaternary system SiO2-Na2O-CaO-Si3N4 and series (II) was a simple substitution of CaF2 for CaO in series (I) glasses keeping the Na:Ca ratio constant. The objective of this work was to evaluate the effect of the variation in nitrogen and fluorine content on the properties of these glasses. The density, glass transition temperature, hardness and elastic modulus all increased linearly with nitrogen content which indicates that the incorporation of nitrogen stiffens the glass network because N is mainly in 3-fold coordination with Si atoms. Fluorine addition significantly decreases the thermal property values but the mechanical properties of these glasses remain unchanged with fluorine. The combination of both nitrogen and fluorine in oxyfluoronitride glasses gives better mechanical properties at much lower melting temperatures since fluorine reduces the melting point, allows higher solubility of nitrogen and does not affect the higher mechanical properties arising from incorporation of nitrogen. The characterization of these N and F substituted bioactive glasses using (29)Si MAS NMR has shown that the increase in rigidity of the glass network can be explained by the formation of SiO3N, SiO2N2 tetrahedra and Q(4) units with extra bridging anions at the expense of Q(3) units. Bioactivity of the glasses was investigated in vitro by examining apatite formation on the surface of glasses treated in acellular simulated body fluid (SBF) with ion

  20. Hydrogen induced surface effects on the mechanical properties of type 304 stainless steel

    International Nuclear Information System (INIS)

    Silva, T.C.V. da; Pascual, R.; Miranda, P.E.V. de.

    1983-01-01

    The possibilities of modifying the mechanical properties of type 304 stainless steel by cathodic hydrogen charging were studied. The situations analysed included hydrogen embrittlement itself in tensile tests of hydrogen containing samples and the effects of delayed cracks in fatigue tests of hydrogenated and outgassed samples. SEM and TEM observations were also performed. It was found that hydrogen induced surface delayed cracks appear in great quantity during outgassing (of the order of several millions in a square centimeter). Hydrogen embrittlement was responsible for drastic losses in ductility in tension, while surface cracks severely reduced fatigue life. (author) [pt

  1. Fission fragment simulation of fusion neutron radiation effects on bulk mechanical properties

    International Nuclear Information System (INIS)

    Van Konynenburg, R.A.; Mitchell, J.B.; Guinan, M.W.; Stuart, R.N.; Borg, R.J.

    1976-01-01

    This research demonstrates the feasibility of using homogeneously-generated fission fragments to simulate high-fluence fusion neutron damage in niobium tensile specimens. This technique makes it possible to measure radiation effects on bulk mechanical properties at high damage states, using conveniently short irradiation times. The primary knock-on spectrum for a fusion reactor is very similar to that produced by fission fragments, and nearly the same ratio of gas atoms to displaced atoms is produced in niobium. The damage from fission fragments is compared to that from fusion neutrons and fission reactor neutrons in terms of experimentally measured yield strength increase, transmission electron microscopy (TEM) observations, and calculated damage energies

  2. Corrosion effect of fast reactor fuel claddings on their mechanical properties

    International Nuclear Information System (INIS)

    Davydov, E.F.; Krykov, F.N.; Shamardin, V.K.

    1985-01-01

    Fast reactor fuel cladding corrosion effect on its mechanical properties was investigated. UO 2 fuel elements were irradiated in the BOP-60 reactor at the linear heat rate of 42 kw/m. Fuel cladding is made of stainless steel OKh16N15M3BR. Calculated maximum cladding temperature is 920 K. Neutron fluence in the central part of fuel elements is 6.3x10 26 m+H- 2 . To investigate the strength changes temperature dependence of corrossion depth, cladding strength reduction factors was determined. Samples plasticity reduction with corrosion layer increase is considered to be a characteristic feature

  3. EFFECT OF PRE-HEAT TREATMENT ON MECHANICAL PROPERTIES OF Ti-6Al-4V WELDS

    Directory of Open Access Journals (Sweden)

    Gnofam Jacques TCHEIN

    2016-11-01

    Full Text Available The work presented here is related to the optimization of the Friction Stir Welding (FSW process. The objective is to study the influence of some parameters used in the production of welded joints by FSW. The most important parameters are the welding speed and the rotational speed of the tool. The effect of pre-heat treatment on the plates to be welded is also studied by the design of experimental methods. These pre-heat treatments result not only in a change of mechanical properties of plates to be welded, but also of their microstructure. The experiments were performed following a 16 lines fractional Taguchi table.

  4. Influence of thermal and radiation effects on microstructural and mechanical properties of Nb-1Zr

    Science.gov (United States)

    Leonard, Keith J.; Busby, Jeremy T.; Zinkle, Steven J.

    2011-07-01

    The microstructural changes and corresponding effects on mechanical properties, electrical resistivity and density of Nb-1Zr were examined following neutron irradiation up to 1.8 dpa at temperatures of 1073, 1223 and 1373 K and compared with material thermally aged for similar exposure times of ˜1100 h. Thermally driven changes in the development of intragranular and grain boundary precipitate phases showed a greater influence on mechanical and physical properties compared to irradiation-induced defects for the examined conditions. Initial formation of the zirconium oxide precipitates was identified as cubic structured plates following a Baker-Nutting orientation relationship to the β-Nb matrix, with particles developing a monoclinic structure on further growth. Tensile properties of the Nb-1Zr samples showed increased strength and reduced elongation following aging and irradiation below 1373 K, with the largest tensile and hardness increases following aging at 1098 K. Tensile properties at 1373 K for the aged and irradiated samples were similar to that of the as-annealed material. Total elongation was lower in the aged material due to a strain hardening response, rather than a weak strain softening observed in the irradiated materials due in part to an irregular distribution of the precipitates in the irradiated materials. Though intergranular fracture surfaces were observed on the 1248 K aged tensile specimens, the aged and irradiated material showed uniform elongations >3% and total elongation >12% for all conditions tested. Cavity formation was observed in material irradiated to 0.9 dpa at 1073 and 1223 K. However, since void densities were estimated to be below 3 × 10 17 m -3 these voids contributed little to either mechanical strengthening of the material or measured density changes.

  5. Freeze-thaw treatment effects on the dynamic mechanical properties of articular cartilage

    Directory of Open Access Journals (Sweden)

    Muldrew Ken

    2010-10-01

    Full Text Available Abstract Background As a relatively non-regenerative tissue, articular cartilage has been targeted for cryopreservation as a method of mitigating a lack of donor tissue availability for transplant surgeries. In addition, subzero storage of articular cartilage has long been used in biomedical studies using various storage temperatures. The current investigation studies the potential for freeze-thaw to affect the mechanical properties of articular cartilage through direct comparison of various subzero storage temperatures. Methods Both subzero storage temperature as well as freezing rate were compared using control samples (4°C and samples stored at either -20°C or -80°C as well as samples first snap frozen in liquid nitrogen (-196°C prior to storage at -80°C. All samples were thawed at 37.5°C to testing temperature (22°C. Complex stiffness and hysteresis characterized load resistance and damping properties using a non-destructive, low force magnitude, dynamic indentation protocol spanning a broad loading rate range to identify the dynamic viscoelastic properties of cartilage. Results Stiffness levels remained unchanged with exposure to the various subzero temperatures. Hysteresis increased in samples snap frozen at -196°C and stored at -80°C, though remained unchanged with exposure to the other storage temperatures. Conclusions Mechanical changes shown are likely due to ice lens creation, where frost heave effects may have caused collagen damage. That storage to -20°C and -80°C did not alter the mechanical properties of articular cartilage shows that when combined with a rapid thawing protocol to 37.5°C, the tissue may successfully be stored at subzero temperatures.

  6. Effects of high-temperature gas dealkalization on surface mechanical properties of float glass

    Science.gov (United States)

    Senturk, Ufuk

    The surface topography, and the near-surface structure and mechanical property changes on float glass, that was treated in atmospheres containing SOsb2, HCl, and 1,1 difluoroethane (DFE) gases, at temperatures in the glass transition region, were studied. Structure was investigated using surface sensitive infrared spectroscopy techniques (attenuated total reflectance (ATR) and diffuse reflectance (DRIFT)) and the topography was evaluated using atomic force microscopy (AFM). The results obtained from the two FTIR methods were in agreement with each other. Mechanical property characteristics of the surface were determined by measuring microhardness using a recording microindentation set-up. A simple analysis performed on the three hardness calculation methods-LVH, LVHsb2, and Lsb2VH-indicated that LVH and LVHsb2 are less effected by measurement errors and are better suited for the calculation of hardness. Contact damage characteristics of the treated glass was also studied by monitoring the crack initiation behavior during indentation, using acoustic emission. The results of the studies, aiming for the understanding of the structure, topography, and hardness property changes indicate that the treatment parameters-temperature, time, and treatment atmosphere conditions-are significant factors influencing these properties. The analysis of these results suggest a relation to exist between the three properties. This relation is used in understanding the surface mechanical properties of the treated float glasses. The difference in the thermal expansion coefficients between the dealkalized surface and bulk, the nature of surface structure changes, structural relaxation, surface water content, and glass transformation temperature are identified as the major factors having an influence on the properties. A model connecting these features is suggested. A difference in the structure, hardness, and topography on the air and tin sides of float glass is also shown to exist. The

  7. Effect of Camphorquinone Concentration in Physical-Mechanical Properties of Experimental Flowable Resin Composites

    Directory of Open Access Journals (Sweden)

    Dayany da Silva Alves Maciel

    2018-01-01

    Full Text Available The aim of this study was to evaluate the effect of camphorquinone concentration in physical-mechanical properties of experimental flowable composites in order to find the concentration that results in maximum conversion, balanced mechanical strength, and minimum shrinkage stress. Model composites based on BISGMA/TEGDMA with 70% wt filler loading were prepared containing different concentrations of camphorquinone (CQ on resin matrix (0.25%, 0.50%, 1%, 1.50%, and 2% by weight. Degree of conversion was determined by FTIR. Surface hardness was assessed before and after 24 h ethanol storage and softening rate was determined. Depth of cure was determined by Knoop hardness evaluation at different depths. Color was assessed by reflectance spectrophotometer, employing the CIE-Lab system. Flexural strength and elastic modulus were determined by a three-point bending test. Shrinkage stress was determined in a Universal Testing Machine in a high compliance system. Data were submitted to ANOVA and Tukey’s test (α = 0.05. The increase in CQ concentration caused a significant increase on flexural strength and luminosity of composites. Surface hardness was not affected by the concentration of CQ. Composite containing 0.25% wt CQ showed lower elastic modulus and shrinkage stress when compared to others. Depth of cure was 3 mm for composite containing 1% CQ and 2 mm for the other tested composites. Degree of conversion was inversely correlated with softening rate and directly correlated with elastic modulus and shrinkage stress. In conclusion, CQ concentration affects polymerization characteristics and mechanical strength of composites. The concentration of CQ in flowable composite for optimized polymerization and properties was 1% wt of the resin matrix, which allows adequate balance among degree of conversion, depth of cure, mechanical properties, and color characteristics of these materials.

  8. Effect of Moisture Content on Mechanical Properties and Terminal Velocity of Berberis

    Directory of Open Access Journals (Sweden)

    E Velayati

    2011-09-01

    Full Text Available The study of mechanical properties of Berberis not only is useful for design and optimization of transportation, processing and packaging equipment but also can prevent mechanical injuries and losses. In this study force, deformation, energy and toughness were measured at different moisture content levels including 70-76, 45-50, 25-30 and 7-10 percent (w.b.. The decrease of moisture content caused increasing rupture force from 1.387 to 2.679 N, decreasing shape deformation from 3.387 to 2.413mm, increasing toughness from 4.297 to 8.220 J/cm3 and decreasing rupture energy from 0.921 to 0.661mJ. Effects of loading speed, force orientation and their interaction were investigated on just fresh Berberis fruit. It was indicated that only force orientation was effective on all investigated properties except toughness. The moisture content was identified as an effective parameter on terminal velocity. It decreased from 9 to 4.5 m/s with decrease of moisture content from 76 to 7 percent (w.b..

  9. Effect of penetrating ionising radiation on the mechanical properties of pericardium

    Energy Technology Data Exchange (ETDEWEB)

    Daar, Eman, E-mail: e.daar@surrey.ac.u [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Woods, E. [Royal Free Hampstead NHS Trust, Pond Street, Hampstead, London NW3 2QG (United Kingdom); Keddie, J.L. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Nisbet, A. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Royal Surrey County Hospital, Guildford (United Kingdom); Bradley, D.A. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom)

    2010-07-21

    The pericardium is an anistropic composite material made up of collagen and elastin fibres embedded in an amorphous matrix mainly composed of proteoglycan and hyaluronan. The collagen fibres are arranged in layers, with different directions of alignment in each layer, giving rise to interesting mechanical properties of pericardium, including the ability to undergo large deformation during performance of regular physiological functions. The present study aims to investigate the effect of penetrating photon ionising radiation on bovine pericardium tissue, being part of a study of the effect of cardiac doses received in breast radiotherapy and the possibility that this can give rise to cardiovascular complications. Irradiation doses in the range 5-80 Gy were used. To characterise the various mechanical properties [elastic modulus, stress relaxation, ultimate tensile strength (UTS) and fracture] a uniaxial tensile test method was applied. The preliminary results reflect the wide inter-sample variations that are expected in dealing with tissues, with only a weak indication of increase in the UTS of the pericardium tissue with increase in radiation dose. Such an effect has also been observed by others, with reduction in UTS at doses of 80 Gy.

  10. Effect of the weld joint configuration on stressed components, residual stresses and mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Cevik, Bekir; Oezer, Alpay; Oezcatalbas, Yusuf [Gazi Univ., Ankara (Turkey)

    2014-03-01

    The effect of the weld joint configuration on components has been studied, which are under service loads, under repair or construction and the residual stresses as well as the mechanical properties of the joint have been determined. For this purpose, a horizontal positioned tensile testing device and a semi-automatic MIG welding machine have been used and then the weld joints of the plates were subjected to different elastic stresses. When the temperature of the joined elements decreased to room temperature, applied elastic stresses were released. By this means, the effects of the existing tensile stresses in the joined parts and the tensile stresses created by the welding processes were investigated. The tensile stresses occurring in the joined elements were determined by using the photo-elasticity analysis method and the hole-drilling method. Also, tensile-shear tests were applied in order to determine the effect of permanent tensile loads on the mechanical properties of the joint. Experimental results showed that the application of corner welded lap joints for components under tensile loading significantly decrease the shear strength and yielding capacities of the joint. (orig.)

  11. Effects of Uncrushed Aggregate on the Mechanical Properties of No-Fines Concrete

    Directory of Open Access Journals (Sweden)

    M. A. Memon

    2018-06-01

    Full Text Available Concrete’s self-weight is a major aspect of a structure’s overall weight. Recently, the use of lightweight concrete (no-fines, foamed and cellular concrete has been increased. Normally no-fines concrete is produced with crushed coarse aggregate of uniform gradation. This study aims to investigate experimentally the effects of the use of uncrushed coarse aggregates on unit weight, compressive and tensile strength of the no-fines (NFC as well as conventional concrete (CC. In addition, the effects of coarse aggregate size on the mechanical properties were also studied. Four gradations of uncrushed coarse aggregates ranging between (5.5-4.75 mm, (10-4.75 mm, (20-4.75 mm and (25-4.75 mm were used for preparing the concretes. The fixed cement-aggregate ratios of 1:6 (with w/c ratio=0.4 and 1:2:4 (with w/c ratio=0.5 were adopted for NFC and CC respectively. It was found that the gradation of uncrushed coarse aggregate has a significant effect on the mechanical properties of NFC. A maximum of 16% reduction in self-weight of the concrete without fines was obtained, as compared to that with fines. Moreover, the compressive strength of no-fines concrete significantly improved by replacing crushed with uncrushed coarse aggregate. The compressive strength increased by 16% for the batch of (25-4.75 mm.

  12. Effect of nickel addition on mechanical properties of powder forged Fe-Cu-C

    Science.gov (United States)

    Archana Barla, Nikki

    2018-03-01

    Fe-Cu-C system is very popular in P/M industry for its good compressibility and dimensional stability with high strength. Fe-Cu-C is a structural material and is used where high strength with high hardness is required. The composition of powder metallurgy steel plays a vital role in the microstructure and physical properties of the sintered component. Fe-2Cu-0.7C-Ni alloy with varying nickel composition (0%, 0.5%, 1.0%, 1.5%, 2.0%, and 3.0%) wt. % was prepared by powder metallurgy (P/M) sinter forging process. The present work discuss the effect of varying nickel content on microstructure and mechanical properties.

  13. Effect of microstructure on mechanical properties and machinability of spheroidal graphite cast iron

    International Nuclear Information System (INIS)

    Kubota, Satoru; Iio, Chinori; Yamaguchi, Shoji; Naito, Daiki; Tomota, Yo; Stefanus, Harjo

    2013-01-01

    Tensile properties, fatigue strength and machinability of spheroidal graphite cast irons with different microstructures were studied. Work-hardening and tensile strength increased with increasing pearlite volume fraction. In situ neutron diffraction during tensile deformation revealed that phase stresses and intergranular stresses are generated with deformation resulting in high work-hardening and high tensile strength with increasing pearlite volume fraction. It was found that graphite grains bear almost no stress, and strongly influence fatigue crack initiation as well as propagation. Therefore graphite refinement is very effective to realize high fatigue strength. The tool life for cutting becomes shorter with increasing pearlite volume fraction. The balance of mechanical properties and machinability was considered. (author)

  14. Effect of Graphene Addition on Mechanical Properties of TiN

    International Nuclear Information System (INIS)

    Shon, In-Jin; Yoon, Jin-Kook; Hong, Kyung-Tae

    2017-01-01

    Despite of many attractive properties of TiN, the current concern about the TiN focuses on its low fracture toughness below the ductile-brittle transition temperature. To improve its mechanical properties, the approach generally utilized has been the addition of a second phase to form composites and to make nanostructured materials. In this respect, highly dense nanostructured TiN and TiN-graphene composites were obtained within two min at 1250 ℃. The grain size of TiN was reduced remarkably by the addition of graphene. The addition of graphene to TiN simultaneously improved the fracture toughness and hardness of TiN-graphene composite due to refinement of TiN and deterring crack propagation by graphene. This study demonstrates that the graphene can be an effective reinforcing agent for improved hardness and fracture toughness of TiN composites.

  15. Effect of elevated temperature on the composition, structure, and mechanical properties of diffusion chromized steel

    International Nuclear Information System (INIS)

    Osintsev, V.D.

    1986-01-01

    The author studies the effect of operating temperature for equipment in contact sections of sulfuric acid workshops on the structure and mechanical properties of the chromized coatings and core of chromized articles. The ferrite lattice spacing was determined in a DRON-0.5 diffractometer according to the line in copper K /sub alpha/ radiation exposure was carried out after layer-by-layer anodic etching of the coating in an aqueous solution. It was shown that diffusion chromizing may lead to a reduction in strength properties compared with those of unchromized steel. As a base for chromized articles intended for operation at temperatures up to 475 0 C it is desirable to use steels 09G2 or 09G25, or for operation at temperatures up to 540 0 C, steels 12KhM and 12MKh

  16. The effects of glucocorticoid on microarchitecture, collagen, mineral and mechanical properties of sheep femur cortical bone

    DEFF Research Database (Denmark)

    Ding, Ming; Danielsen, Carl C; Overgaard, Søren

    2010-01-01

    The effects of glucocorticoid on microarchitecture, collagen, mineral and mechanical properties of sheep femur cortical bone – Validation of large animal model for tissue engineering and biomaterial research Ming Ding,1* Carl Christian Danielsen,2 Søren Overgaard1 1Orthopaedic Research Laboratory......, Department of Orthopaedics and Traumatology, Odense University Hospital, Institute of Clinical Research, University of Southern Denmark, Odense C, Denmark 2Department of Connective Tissue Biology, Institute of Anatomy, University of Aarhus, Aarhus C, Denmark Osteopenia in sheep has been successfully induced...... by glucocorticoid treatment and the changes in properties of cancellous bone were comparable with those observed in humans after long-term glucocorticoid treatment. However, the influence on cortical bone has not been thoroughly elucidated. This study aimed to investigate the influence of glucocorticoid on sheep...

  17. Effect of Graphene Addition on Mechanical Properties of TiN

    Energy Technology Data Exchange (ETDEWEB)

    Shon, In-Jin [Chonbuk National University, Jeonju (Korea, Republic of); Yoon, Jin-Kook; Hong, Kyung-Tae [Korea Institute of Science and Technology, Seoul (Korea, Republic of)

    2017-03-15

    Despite of many attractive properties of TiN, the current concern about the TiN focuses on its low fracture toughness below the ductile-brittle transition temperature. To improve its mechanical properties, the approach generally utilized has been the addition of a second phase to form composites and to make nanostructured materials. In this respect, highly dense nanostructured TiN and TiN-graphene composites were obtained within two min at 1250 ℃. The grain size of TiN was reduced remarkably by the addition of graphene. The addition of graphene to TiN simultaneously improved the fracture toughness and hardness of TiN-graphene composite due to refinement of TiN and deterring crack propagation by graphene. This study demonstrates that the graphene can be an effective reinforcing agent for improved hardness and fracture toughness of TiN composites.

  18. Effect of flexible fuels on mechanical properties of reinforced polyoxymethylenes (POM

    Directory of Open Access Journals (Sweden)

    M. Gómez-Mares

    2014-08-01

    Full Text Available The use of flexible fuels has been increased during the last years making essential to run compatibility tests with those materials exposed to them. In this work the effect of the flexible fuels M15A (Volume Mixture of 85% fuel C and 15 % Aggressive methanol and M30A (Volume mixture of 70% fuel C and 30 % Aggressive methanol on the mechanical properties of some polymers of the Polyoxymethylene (POM family is assessed. The polymers chosen had different levels of glass fiber filler (0, 10 and 25%. The samples were immersed on fuel and kept on a chamber at 80°C during 1008h. The results showed that the properties of polymers with filler are more affected than the ones of the polymers without it. Tensile stress at break and Tensile stress at yield diminished with the fuel exposure. The most aggressive fuel was found to be M30A, due to the higher methanol concentration.

  19. The crucial effect of early-stage gelation on the mechanical properties of cement hydrates

    Science.gov (United States)

    Ioannidou, Katerina; Kanduč, Matej; Li, Lunna; Frenkel, Daan; Dobnikar, Jure; Del Gado, Emanuela

    2016-07-01

    Gelation and densification of calcium-silicate-hydrate take place during cement hydration. Both processes are crucial for the development of cement strength, and for the long-term evolution of concrete structures. However, the physicochemical environment evolves during cement formation, making it difficult to disentangle what factors are crucial for the mechanical properties. Here we use Monte Carlo and Molecular Dynamics simulations to study a coarse-grained model of cement formation, and investigate the equilibrium and arrested states. We can correlate the various structures with the time evolution of the interactions between the nano-hydrates during the preparation of cement. The novel emerging picture is that the changes of the physicochemical environment, which dictate the evolution of the effective interactions, specifically favour the early gel formation and its continuous densification. Our observations help us understand how cement attains its unique strength and may help in the rational design of the properties of cement and related materials.

  20. The effect of irradiation on the mechanical properties of 6061-T651 aluminum

    International Nuclear Information System (INIS)

    Alexander, D.J.

    1992-01-01

    Critical components of the Advanced Neutron Source (ANS) reactor, to be built at Oak Ridge National Laboratory (ORNL), will be fabricated from 6061-T651 aluminum alloy. This alloy has been selected for its favorable neutronic, thermal, and mechanical properties. The effect of irradiation on the tensile properties and fracture toughness has been studied to allow the lifetime of these components to be estimated. Irradiations were carried out in the High Flux Isotope Reactor at ORNL at a temperature of approximately 95 degree C to a fluence of approximately 10 26 m -2 (thermal). Testing was conducted from room temperature to 150 degree C. The yield and ultimate tensile strengths were increased by irradiation, and the total elongation decreased, but the fracture toughness at 26 and 95 degree C was not degraded by irradiation, and decreased only slightly at 150 degree C

  1. Effect of neutron radiation on mechanical properties of permanent near core structures

    International Nuclear Information System (INIS)

    Tavassoli, A.A.

    1988-01-01

    Several hundred specimens have been tested in order to assess the effects of low dose neutron radiation ( 0 C and ductility and toughness are primary design concerns, the changes provoked, by doses up to 1.3 dpa, in overall mechanical properties of welded joints are small. For upper core structure, where the operating temperature is about 550 0 C and fatigue and creep resistance are major design needs, the changes induced, through formation of up to about 2 appm helium, in conventional fatigue properties or fatigue with short hold times are negligible. With increasing hold time, intergranular rupture in irradiated specimens is enhanced but the limited number of tests does not allow definite conclusions to be drawn. 53 refs, 3 tabs, 9 figs

  2. Effects of holding pressure and process temperatures on the mechanical properties of moulded metallic parts

    DEFF Research Database (Denmark)

    Islam, Aminul; Hansen, Hans Nørgaard; Esteves, N.M.

    2013-01-01

    Metal injection moulding is gaining more and more importance over the time and needs more research to be done to understand the sensitivity of process to different process parameters. The current paper makes an attempt to better understand the effects of holding pressure and process temperatures...... on the moulded metallic parts. Stainless steel 316L is used in the investigation to produce the specimen by metal injection moulding (MIM) and multiple analyses were carried out on samples produced with different combinations of holding pressure, mould temperature and melt temperature. Finally, the parts were...... characterized to investigate mechanical properties like density, ultimate tensile strength, shrinkage etc. The results are discussed in the paper. The main conclusion from this study is unlike plastic moulding, the tensile properties of MIM parts doesn’t vary based on the flow direction of the melt, and tensile...

  3. Effect of welding speed on microstructural and mechanical properties of friction stir welded Inconel 600

    International Nuclear Information System (INIS)

    Song, K.H.; Fujii, H.; Nakata, K.

    2009-01-01

    In order to evaluate the properties of a friction stir welded Ni base alloy, Inconel 600 (single phase type) was selected. Sound friction stir welds without weld defect were obtained at 150 and 200 mm/min in welding speed, however, a groove like defect occurred at 250 mm/min. The electron back scattered diffraction (EBSD) method was used to analyze the grain boundary character distribution. As a result, dynamic recrystallization was observed at all conditions, and the grain refinement was achieved in the stir zone, and it was gradually accelerated from 19 μm in average grain size of the base material to 3.4 μm in the stir zone with increasing the welding speed. It also has an effect on the mechanical properties so that friction stir welded zone showed 20% higher microhardness and 10% higher tensile strength than those of base material.

  4. Effect of Mo content on thermal and mechanical properties of Mo–Ru–Rh–Pd alloys

    International Nuclear Information System (INIS)

    Masahira, Yusuke; Ohishi, Yuji; Kurosaki, Ken; Muta, Hiroaki; Yamanaka, Shinsuke; Komamine, Satoshi; Fukui, Toshiki; Ochi, Eiji

    2015-01-01

    Metallic inclusions are precipitated in irradiated oxide fuels. The composition of the phases varies with the burnup and the conditions such as temperature gradients and oxygen potential of the fuel. In the present work, Mo x/(0.7+x) (Ru 0.5 Rh 0.1 Pd 0.1 ) (0.7)/(0.7+x) (x = 0, 0.05, 0.1, 0.15, 0.2, and 0.25) alloys were prepared by arc melting, followed by annealing in a high vacuum. The thermal and mechanical properties of the alloys such as elastic moduli, Debye temperature, micro-Vickers hardness, electrical resistivity, and thermal conductivity have been evaluated to elucidate the effect of Mo content on these physical properties of the alloys. The alloys with lower Mo contents show higher thermal conductivity. The thermal conductivity of the alloy with x = 0 is almost twice of that of the alloy with x = 0.25. The thermal conductivities of the alloys are dominated by electronic contribution, which has been evaluated using the Wiedemann–Franz–Lorenz relation from the electrical resistivity data. It is confirmed that the variation of the Mo contents of the alloys considerably affects the mechanical and thermal properties of the alloys

  5. Effects of ethyl cellulose on the crystallization and mechanical properties of poly(β-hydroxybutyrate).

    Science.gov (United States)

    Chen, Jianxiang; Wu, Defeng; Pan, Keren

    2016-07-01

    Ethyl cellulose (EC) was blended with poly(β-hydroxybutyrate) (PHB), aiming at controlling crystallization and mechanical properties of PHB. The obtained PHB/EC blend is an immiscible system, and the discrete EC phase behaves dual characteristics in the PHB matrix, as the viscoelastic droplets during processing, and as the rigid filler particles during shear flow. This is confirmed by the rheological tests. The presence of EC domains acts as the tackifier, sharply increasing system viscosity from 1000Pas to 5000Pas, and as a result, has large influence on the spherulite morphology of PHB and its crystallization kinetics. The PHB spherulite growth rate reduces in the presence of inert EC, accompanied by decreased degree of crystallinity and reduced lamella defects. These affect the mechanical properties of PHB strongly, together with reinforcing effect of EC itself. At the lower content level, EC can act as both reinforcement and toughener. The presence of 1wt% EC enhances the tensile strength of PHB by about 22%, from 27.5MPa to 33.3MPa, accompanied by 15% increase of impact strength. This work provide an easy way to control the structure and properties of PHB using EC. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Effect of Pr addition on microstructure and mechanical properties of AZ61 magnesium alloy

    Directory of Open Access Journals (Sweden)

    You Zhiyong

    2014-03-01

    Full Text Available To improve the strength, hardness and heat resistance of Mg-6Al-1Zn (AZ61 alloy, the effects of Pr addition on the as-cast microstructure and mechanical properties of AZ61 alloy were investigated at room and elevated temperatures by means of Brinell hardness measurement, optical microscope (OM, scanning electron microscope (SEM, energy dispersive spectroscopy (EDS, X-ray diffractometer (XRD and DNS100 electronic universal testing machine. The results show that the microstructures of Pr-containing AZ61 alloys were refined, with primary β-Mg17Al12 phase distributed homogeneously. When the addition of Pr is up to 1.2wt.%, the β phase becomes finer, and new needle-like or short-rod shaped Al11Pr3 phase and blocky AlPr phase appear. As a result, optimal tensile properties are obtained. However, greater than 1.2wt.% Pr addition leads to poorer mechanical properties due to the aggregation of the needle-like phase and large size of grains. The present research findings provide a new way for strengthening of magnesium alloys at room and elevated temperatures, and a method of producing thermally-stable AZ61 magnesium alloy.

  7. EFFECTS OF ETHYLENE VINYL ACETATE CONTENT ON PHYSICAL AND MECHANICAL PROPERTIES OF WOOD-PLASTIC COMPOSITES

    Directory of Open Access Journals (Sweden)

    Dongfang Li,

    2012-05-01

    Full Text Available To investigate the effects of different ethylene vinyl acetate (EVA contents on the performance of wood plastic composites (WPCs made from poplar wood flour (PWF and high density polyethylene (HDPE, physical properties tests, mechanical properties tests, and scanning electron microscope (SEM tests were employed. The thermal stability and functional groups of PWF treated by EVA were evaluated by thermogravimetric analysis (TGA, differential thermal analysis (DTA, and Fourier transform infrared spectroscopy (FTIR, respectively. The results showed that the hardness, water uptake, and thickness swelling of the WPCs was reduced with increasing content of EVA. The MOR and tensile strength of the WPC treated by 15% EVA content were enhanced by 17.48% and 9.97%, respectively, compared with those of the WPC without EVA. TGA results showed that the thermal stability of PWF treated by EVA was improved. FTIR analysis indicated that PWF was reacted and coated with EVA. SEM results showed that gaps and voids hardly existed in the sections of the WPCs treated by EVA. This research suggests that the flexibility and mechanical properties of WPCs could be improved by adding EVA. The best condition of EVA content could be 15%.

  8. The effects of gamma radiation and electron beam on the mechanical properties of polypropylene dominant natural rubber blend

    International Nuclear Information System (INIS)

    Mar Mar Oo; Khairul Zaman; Tin Hlaing

    2001-01-01

    The effects of irradiation, with dose ranging from 20 to 100 kGy on the mechanical properties of polypropylene and natural rubber blends (PP/NR blends) were investigated. Crosslinking of the PP/NR blends proved to play a major role in the improvement of the mechanical properties of the blend. The results also revealed that the blend composition the enhancement in properties depend on the irradiation dose and on the concentration of the crosslinking agent. (author)

  9. The effect of phosphorus on the microstructure and mechanical properties of ATI 718Plus alloy

    International Nuclear Information System (INIS)

    Wang, Minqing; Du, Jinhui; Deng, Qun; Tian, Zhiling; Zhu, Jing

    2015-01-01

    Since the discovery in the 1990s of the abnormal improvement produced by phosphorus in the stress rupture and creep life of Inconel 718 (hereafter referred to as 718), a great deal of additional research followed. However, the mechanism of the action of phosphorous in 718 is still in question. This paper details an experimental study that was intended to determine how phosphorus acts upon the microstructure and mechanical properties of Ni–Fe based alloy 718Plus. The results show that phosphorus has little effect on the strength and ductility of alloy 718Plus, but can significantly improve the stress rupture life. Phase constituents such as the δ and γ′ phases were quantitatively analyzed using electrolytic phase isolation and micro-chemical and XRD analysis as the phosphorous content of the alloy was increased. A full atom mapping of the distribution of phosphorus in the 718Plus alloy was quantitatively determined using APT (Atom Probe Tomography) technique. The results showed that there is no significant segregation of phosphorus at the γ′/γ and γ′/γ′ interface, but it significantly segregates at the grain boundaries and δ/γ interface. It was found that phosphorus is extremely depleted in the δ phase, which is believed to inhibit δ-phase precipitation by preventing δ phase nucleation and growth in the 718Plus alloy. Finally, the influence of phosphorus on the microstructure and mechanical properties of the 718Plus alloy was discussed

  10. The effect of phosphorus on the microstructure and mechanical properties of ATI 718Plus alloy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Minqing, E-mail: minqingw@yahoo.com [Central Iron and Steel Research Institute, Beijing 100081 (China); School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Beijing Key Laboratory of Advanced High Temperature Materials, Beijing 100081 (China); Du, Jinhui; Deng, Qun [Central Iron and Steel Research Institute, Beijing 100081 (China); Beijing Key Laboratory of Advanced High Temperature Materials, Beijing 100081 (China); Tian, Zhiling [Central Iron and Steel Research Institute, Beijing 100081 (China); Zhu, Jing, E-mail: jzhu@mail.tsinghua.edu.cn [School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2015-02-25

    Since the discovery in the 1990s of the abnormal improvement produced by phosphorus in the stress rupture and creep life of Inconel 718 (hereafter referred to as 718), a great deal of additional research followed. However, the mechanism of the action of phosphorous in 718 is still in question. This paper details an experimental study that was intended to determine how phosphorus acts upon the microstructure and mechanical properties of Ni–Fe based alloy 718Plus. The results show that phosphorus has little effect on the strength and ductility of alloy 718Plus, but can significantly improve the stress rupture life. Phase constituents such as the δ and γ′ phases were quantitatively analyzed using electrolytic phase isolation and micro-chemical and XRD analysis as the phosphorous content of the alloy was increased. A full atom mapping of the distribution of phosphorus in the 718Plus alloy was quantitatively determined using APT (Atom Probe Tomography) technique. The results showed that there is no significant segregation of phosphorus at the γ′/γ and γ′/γ′ interface, but it significantly segregates at the grain boundaries and δ/γ interface. It was found that phosphorus is extremely depleted in the δ phase, which is believed to inhibit δ-phase precipitation by preventing δ phase nucleation and growth in the 718Plus alloy. Finally, the influence of phosphorus on the microstructure and mechanical properties of the 718Plus alloy was discussed.

  11. Effect of reinforcement nanoparticles addition on mechanical properties of SBS/curaua fiber composites

    Energy Technology Data Exchange (ETDEWEB)

    Borba, Patricia M. [Servico Nacional de Aprendizagem Industrial (CETEPO/SENAI/RS), Sao Leopoldo, RS (Brazil). Centro Tecnologico de Polimeros; Tedesco, Adriana [Braskem S. A., III Polo Petroquimico, Triunfo, RS (Brazil); Lenz, Denise M., E-mail: denise.lenz@gmail.com [Universidade Luterana do Brasil (ULBRA), Canoas, RS (Brazil). Programa de Pos-graduacao em Engenharia de Materiais e Processos Sustentaveis

    2014-03-15

    Composites of styrene-butadiene-styrene triblock copolymer (SBS) matrix with curauá fiber and/or a nanoparticulated mineral (montmorillonite clay - MMT) used as reinforcing agents were prepared by melt-mixing. The influence of clay addition on properties like tensile and tear strength, rebound resilience, flex fatigue life, abrasion loss, hardness and water absorption of composites with 5, 10 and 20 wt% of curauá fiber was evaluated in presence of maleic anhydride grafted styrene-(ethylene-co-butylene)-styrene triblock copolymer (MA-g-SEBS) coupling agent. Furthermore, the effect of mineral plasticizer loading on tensile strength of selected composites was investigated. The hybrid SBS composite that showed the best overall mechanical performance was composed by 2 wt% of MMT and 5 wt% of curauá fiber. Increasing fiber content up to 20 wt% resulted in a general decrease in all mechanical properties as well as incorporation of 5 wt% MMT caused a decrease in the tensile strength in all fiber contents. The hybrid composites showed clay agglomerates (tactoids) poorly dispersed that could explain the poor mechanical performance of composites at higher concentrations of curauá fiber and MMT nanoparticles. The addition of plasticizer further decreased the tensile strength while the addition of MMT nanoparticles decreased water absorption for all SBS composites. (author)

  12. Mechanical properties and shape memory effect of thermal-responsive polymer based on PVA

    Science.gov (United States)

    Lin, Liulan; Zhang, Lingfeng; Guo, Yanwei

    2018-01-01

    In this study, the effect of content of glutaraldehyde (GA) on the shape memory behavior of a shape memory polymer based on polyvinyl alcohol chemically cross-linked with GA was investigated. Thermal-responsive shape memory composites with three different GA levels, GA-PVA (3 wt%, 5 wt%, 7 wt%), were prepared by particle melting, mold forming and freeze-drying technique. The mechanical properties, thermal properties and shape memory behavior were measured by differential scanning calorimeter, physical bending test and cyclic thermo-mechanical test. The addition of GA to PVA led to a steady shape memory transition temperature and an improved mechanical compressive strength. The composite with 5 wt% of GA exhibited the best shape recoverability. Further increase in the crosslinking agent content of GA would reduce the recovery force and prolong the recovery time due to restriction in the movement of the soft PVA chain segments. These results provide important information for the study on materials in 4D printing.

  13. Effects of deep cryogenic treatment on the microstructure and mechanical properties of commercial pure zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Chao; Wang, Yunpeng; Sang, Deli; Li, Yijun; Jing, Lei; Fu, Ruidong, E-mail: rdfu@ysu.edu.cn; Zhang, Xiangyi

    2015-01-15

    Highlights: • The microstructure and mechanical properties of DCT-treated Zr were investigated. • DCT induced a change in grain orientation and improved internal stress. • Changes in grain orientation and internal stress increased dislocation density. • Hardness in basal planes was significantly larger than that in prism planes. • Strength levels were high and good ductility could still be achieved after DCT. - Abstract: The effects of deep cryogenic treatment (DCT) on the microstructure and mechanical properties of commercial pure zirconium were investigated. Experimental results indicated that DCT induced a change in grain orientation and improved internal stress, which in turn increased dislocation density that led to improved hardness. Hardness in basal planes was found to be significantly larger than that in prism planes. Moreover, strength was enhanced in DCT-treated zirconium and the ductility was comparable to that of as-annealed zirconium. This phenomenon was due to the increase in dislocation density and the good ductility resulting from the motion of pre-existing dislocations and specific dislocation configurations. DCT led to the transformation of tensile fracture mode from mixed-rupture characteristics of quasi-cleavage and dimples to quasi-cleavage, thereby increasing compatible deformation capabilities. The possible mechanisms underlying microstructural modification, tensile strength, and hardness improvement were discussed.

  14. Effects of Bi Addition on the Microstructure and Mechanical Properties of Nanocrystalline Ag Coatings

    Directory of Open Access Journals (Sweden)

    Yuxin Wang

    2017-08-01

    Full Text Available In this study we investigated the effects of Bi addition on the microstructure and mechanical properties of an electrodeposited nanocrystalline Ag coating. Microstructural features were investigated with transmission electron microscopy (TEM. The results indicate that the addition of Bi introduced nanometer-scale Ag-Bi solid solution particles and more internal defects to the initial Ag microstructures. The anisotropic elastic-plastic properties of the Ag nanocrystalline coating with and without Bi addition were examined with nanoindentation experiments in conjunction with the recently-developed inverse method. The results indicate that the as-deposited nanocrystalline Ag coating contained high mechanical anisotropy. With the addition of 1 atomic percent (at% Bi, the anisotropy within Ag-Bi coating was very small, and yield strength of the nanocrystalline Ag-Bi alloy in both longitudinal and transverse directions were improved by over 100% compared to that of Ag. On the other hand, the strain-hardening exponent of Ag-Bi was reduced to 0.055 from the original 0.16 of the Ag coating. Furthermore, the addition of Bi only slightly increased the electrical resistivity of the Ag-Bi coating in comparison to Ag. Results of our study indicate that Bi addition is a promising method for improving the mechanical and physical performances of Ag coating for electrical contacts.

  15. Effects of deep cryogenic treatment on the microstructure and mechanical properties of commercial pure zirconium

    International Nuclear Information System (INIS)

    Yuan, Chao; Wang, Yunpeng; Sang, Deli; Li, Yijun; Jing, Lei; Fu, Ruidong; Zhang, Xiangyi

    2015-01-01

    Highlights: • The microstructure and mechanical properties of DCT-treated Zr were investigated. • DCT induced a change in grain orientation and improved internal stress. • Changes in grain orientation and internal stress increased dislocation density. • Hardness in basal planes was significantly larger than that in prism planes. • Strength levels were high and good ductility could still be achieved after DCT. - Abstract: The effects of deep cryogenic treatment (DCT) on the microstructure and mechanical properties of commercial pure zirconium were investigated. Experimental results indicated that DCT induced a change in grain orientation and improved internal stress, which in turn increased dislocation density that led to improved hardness. Hardness in basal planes was found to be significantly larger than that in prism planes. Moreover, strength was enhanced in DCT-treated zirconium and the ductility was comparable to that of as-annealed zirconium. This phenomenon was due to the increase in dislocation density and the good ductility resulting from the motion of pre-existing dislocations and specific dislocation configurations. DCT led to the transformation of tensile fracture mode from mixed-rupture characteristics of quasi-cleavage and dimples to quasi-cleavage, thereby increasing compatible deformation capabilities. The possible mechanisms underlying microstructural modification, tensile strength, and hardness improvement were discussed

  16. Effects of mechanical properties and geometric conditions on stiffness of Hyperboloid Shallow Shell

    Directory of Open Access Journals (Sweden)

    Zhao Lihong

    2015-01-01

    Full Text Available The experiment models based on the hyperboloid shallow shells that represent automobile panel's surface features are established. The effects of material properties and geometric conditions condition on the stiffness of hyperboloid shallow shell are investigated experimentally. The influences of panel thickness and geometric conditions on stiffness are very obvious. Stiffness increases with increasing of the panel thickness, and stiffness doubled as increasing in thickness with 0.1 mm. The effect of thickness on stiffness is far greater than that of blank holding force. The greater the arc height of punch, the greater the stiffness. And stiffness increases nearly by five times with arc height of punch is from 3mm to 9mm. The effect of arc height of punch on stiffness is far greater than that of materials mechanical properties. The stiffness is varied with different panel material properties by the same forming and stiffness test conditions. The decrease of yield strength is beneficial to the panel stiffness. The appropriate choice of materials and forming process condition is important in meeting necessary requirements for the energy-saving, lightweight and reducing wind resistance design in automotive industry.

  17. Effect of water absorption on the mechanical properties of poly(3-hydroxybutyrate)/vegetable fiber composites

    Science.gov (United States)

    Marinho, Vithória A. D.; Carvalho, Laura H.; Canedo, Eduardo L.

    2015-05-01

    The present work studies the effect of water absorption on the performance of composites of poly(3-hydroxybutyrate) (PHB) - a fully biodegradable semi-crystalline thermoplastic obtained from renewable resources through low-impact biotechnological process, biocompatible and non-toxic - and vegetable fiber from the fruit (coconut) of babassu palm tree.Water resistance is an important characteristic of structural composites, that may exposed to rain and humid environments. Both water absorption capacity (water solubility in the material) and the rate of water absorption (controlled by the diffusivity of water in the material) are important parameters. However, water absorption per se may not be the most important characteristic, insofar as the performance and applications of the compounds. It is the effect of the water content on the ultimate properties that determine the suitability of the material for applications that involve prolonged exposure to water.PHB/babassu composites with 0-20% load were prepared in an internal mixer. Two different types of babassu fibers having two different article size ranges were compounded with PHB and test specimens molded by compression. The water absorption capacity and the kinetic constant of water absorption were measured in triplicate. Mechanical properties under tension were measured for dry and moist specimens with different amounts of absorbed water.Results indicate that the performance of the composites is comparable to that of the pure matrix. Water absorption capacity increases from 0.7% (pure PHB) to 4% (PHB/20% babassu), but the water diffusivity (4.10□8 cm2/s) was found to be virtually independent of the water absorption level. Water absorption results in moderate drop in elastic modulus (10-30% at saturation, according to fiber content) but has little effect on tensile strength and elongation at break. Fiber type and initial particle size do not have a significant effect on water absorption or mechanical properties.

  18. Hygrothermal effect of salt water environments on mechanical properties of carbon/epoxy composites

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Young Eun; Yoon, Sung Ho [Kumoh Nat' l Institute of Technology, Gumi (Korea, Republic of)

    2012-10-15

    In this study, salt water immersion tests were experimentally performed for up to 12 months to investigate the hygrothermal effect of salt water environments on the mechanical properties of carbon/epoxy composites. The composites were manufactured by laminating prepregs composed of carbon plain woven fabric and epoxy resin. The specimens were subjected to temperatures of 35, 55, and 75 .deg. C while being exposed to the salt water environments. Mechanical test results showed that the tensile modulus and tensile strength decreased at a small rate, and the compressive modulus and compressive strength decreased at a relatively larger rate, as the exposure temperature and time increased. The rate of decrease in compressive strength became larger as the exposure temperature became higher. This is because a higher environmental temperature accelerates the salt water uptake; this, in turn, reduces the compressive strength more rapidly.

  19. Extractive and anatomical wood structure effects on mechanical properties of Caoba wood (Swietenia macrophylla King)

    International Nuclear Information System (INIS)

    Arevalo Fuentes Rosven Libardo; Hernandez Roger

    2008-01-01

    The compression tangential to grain of samples of mahogany wood from Peru was examined at different relative humidity levels at 25 Celsius degrade to determine the influence of both extractives and anatomical structure. Matched samples were used to assess the percentage of extractive components by extraction with solvents of increasing polarity: cyclohexane, dichloromethane, acetone, methanol and hot water. Additionally, fourteen anatomical parameters were determined by image analysis. Stepwise regression analysis concluded that mainly anatomical features, such as rays and vessels, rather than extractives, affect the mechanical behaviour of mahogany. These findings are agree with earlier results showing a negative effect of large and multiseriate rays on the mechanical properties of wood when loaded perpendicularly to their long axis. The influence of lumen located extracts soluble in dichloromethane might disallow deformations. Finally, it is postulated that hot water extracts may play a plasticizing role in this species.

  20. The effects of weathering on the physical and mechanical properties of igneous and metamorphic saprolites

    DEFF Research Database (Denmark)

    Rocchi, Irene; Coop, M. R.; Maccarini, M.

    2017-01-01

    The present paper presents three extensive datasets of laboratory testing on weathered geomaterials, which are emblematic of soil types widely found worldwide. The overall dataset includes soils originating from igneous and metamorphic rocks, either coarse or fine grained and having either felsic...... or mafic minerals. In particular, the data are interpreted to highlight the effects that weathering has on the physical and mechanical properties of these natural geomaterials comparing them with published data with the aim to provide a general framework of interpretation that takes into account...... this geological process and links soil mechanics to engineering geology. Generally, weathering induces a reduction in the grain size, both due to physical actions (e.g. opening of grain contacts) and to the chemical decomposition of minerals resulting in the formation of clay minerals. As weathering proceeds...

  1. Evaluation of the electron beam radiation effects on the mechanical properties of the polypropylene

    International Nuclear Information System (INIS)

    Souza, Clecia M.; Moura, Esperidiana A.B.; Chinellato, Anne

    2009-01-01

    This paper studied the electron beam radiation effects on the mechanical properties of the polypropylene (PP) resin. The PP resin was submitted to 150-250 kGy radiation dose, at the dose rate of 14 kGy/s, room temperature and presence of air, using a 1.5 MeV electron accelerator. After the irradiation, the irradiated and non irradiated resin samples were submitted to the mechanical testes of traction resistance and impact Izod resistance. The results shown that the traction resistance at drainage of PP samples have not experienced significant modifications (p < 0.05) after the irradiation. However, the original PP rupture resistance (non irradiated samples) presented a gain up to 100 % as function of the applied radiation dose; the percentage of deformation in the rupture presented a reduction up to 65 % and the Izod impact resistance presented a reduction up to 70 % with the increase of the radiation dose (p < 0.05)

  2. Hygrothermal effect of salt water environments on mechanical properties of carbon/epoxy composites

    International Nuclear Information System (INIS)

    Hwang, Young Eun; Yoon, Sung Ho

    2012-01-01

    In this study, salt water immersion tests were experimentally performed for up to 12 months to investigate the hygrothermal effect of salt water environments on the mechanical properties of carbon/epoxy composites. The composites were manufactured by laminating prepregs composed of carbon plain woven fabric and epoxy resin. The specimens were subjected to temperatures of 35, 55, and 75 .deg. C while being exposed to the salt water environments. Mechanical test results showed that the tensile modulus and tensile strength decreased at a small rate, and the compressive modulus and compressive strength decreased at a relatively larger rate, as the exposure temperature and time increased. The rate of decrease in compressive strength became larger as the exposure temperature became higher. This is because a higher environmental temperature accelerates the salt water uptake; this, in turn, reduces the compressive strength more rapidly

  3. Effect of rhenium irradiations on the mechanical properties of tungsten for nuclear fusion applications

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Aneeqa, E-mail: aneeqa.khan-3@postgrad.manchester.ac.uk [School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, M13 9PL (United Kingdom); Elliman, Robert; Corr, Cormac [Research School of Physics and Engineering, The Australian National University, Canberra, ACT 2601 (Australia); Lim, Joven J.H.; Forrest, Andrew [School of Materials, The University of Manchester, M13 9PL (United Kingdom); Mummery, Paul [School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, M13 9PL (United Kingdom); Evans, Llion M. [Culham Centre for Fusion Energy, Culham Science Centre, Abingdon, Oxon, OX14 3DB (United Kingdom)

    2016-08-15

    As-received and annealed tungsten samples were irradiated at a temperature of 400 °C with Re and W ions to peak concentrations of 1600 appm (atomic parts per million) and damage levels of 40 dpa (displacements per atom). Mechanical properties were investigated using nanoindentation, and the orientation and depth dependence of irradiation damage was investigated using Electron Back Scatter Diffraction (EBSD). Following irradiation there was a 13% increase in hardness in the as received sheet and a 23% increase in the annealed material for both tungsten and rhenium irradiation. The difference between the tungsten and rhenium irradiated samples was negligible, suggesting that for the concentrations and damage levels employed, the presence of rhenium does not have a significant effect on the hardening mechanism. Energy dependent EBSD of annealed samples provided information about the depth distribution of the radiation damage in individual tungsten grains and confirmed that the radiation damage is orientation dependant.

  4. Study of Effects on Mechanical Properties of PLA Filament which is blended with Recycled PLA Materials

    Science.gov (United States)

    Babagowda; Kadadevara Math, R. S.; Goutham, R.; Srinivas Prasad, K. R.

    2018-02-01

    Fused deposition modeling is a rapidly growing additive manufacturing technology due to its ability to build functional parts having complex geometry. The mechanical properties of the build part is depends on several process parameters and build material of the printed specimen. The aim of this study is to characterize and optimize the parameters such as layer thickness and PLA build material which is mixed with recycled PLA material. Tensile and flexural or bending test are carried out to determine the mechanical response characteristics of the printed specimen. Taguchi method is used for number of experiments and Taguchi S/N ratio is used to identify the set of parameters which give good results for respective response characteristics, effectiveness of each parameters is investigated by using analysis of variance (ANOVA).

  5. Composition and grain size effects on the structural and mechanical properties of CuZr nanoglasses

    International Nuclear Information System (INIS)

    Adibi, Sara; Branicio, Paulo S.; Zhang, Yong-Wei; Joshi, Shailendra P.

    2014-01-01

    Nanoglasses (NGs), metallic glasses (MGs) with a nanoscale grain structure, have the potential to considerably increase the ductility of traditional MGs while retaining their outstanding mechanical properties. We investigated the effects of composition on the structural and mechanical properties of CuZr NG films with grain sizes between 3 to 15 nm using molecular dynamics simulations. Results indicate a transition from localized shear banding to homogeneous superplastic flow with decreasing grain size, although the critical average grain size depends on composition: 5 nm for Cu 36 Zr 64 and 3 nm for Cu 64 Zr 36 . The flow stress of the superplastic NG at different compositions follows the trend of the yield stress of the parent MG, i.e., Cu 36 Zr 64 yield/flow stress: 2.54 GPa/1.29 GPa and Cu 64 Zr 36 yield/flow stress: 3.57 GPa /1.58 GPa. Structural analysis indicates that the differences in mechanical behavior as a function of composition are rooted at the distinct statistics of prominent atomic Voronoi polyhedra. The mechanical behavior of NGs is also affected by the grain boundary thickness and the fraction of atoms at interfaces for a given average grain size. The results suggest that the composition dependence of the mechanical behavior of NGs follows that of their parent MGs, e.g., a stronger MG will generate a stronger NG, while the intrinsic tendency for homogeneous deformation occurring at small grain size is not affected by composition.

  6. Phase Morphology and Mechanical Properties of Cyclic Butylene Terephthalate Oligomer-Containing Rubbers: Effect of Mixing Temperature

    OpenAIRE

    Hal?sz, Istv?n Zolt?n; B?r?ny, Tam?s

    2016-01-01

    In this work, the effect of mixing temperature (Tmix) on the mechanical, rheological, and morphological properties of rubber/cyclic butylene terephthalate (CBT) oligomer compounds was studied. Apolar (styrene butadiene rubber, SBR) and polar (acrylonitrile butadiene rubber, NBR) rubbers were modified by CBT (20 phr) for reinforcement and viscosity reduction. The mechanical properties were determined in tensile, tear, and dynamical mechanical analysis (DMTA) tests. The CBT-caused viscosity cha...

  7. The effects of topology on the structural, dynamic and mechanical properties of network-forming materials

    International Nuclear Information System (INIS)

    Wilson, Mark

    2012-01-01

    The effects of network topology on the static structural, mechanical and dynamic properties of MX 2 network-forming liquids (with tetrahedral short-range order) are discussed. The network topology is controlled via a single model parameter (the anion polarizability) which effectively constrains the inter-tetrahedral linkages in a physically transparent manner. Critically, it is found to control the balance between the stability of corner- and edge-sharing tetrahedra. A potential rigidity transformation is investigated. The vibrational density of states is investigated, using an instantaneous normal model analysis, as a function of both anion polarizability and temperature. A low frequency peak is seen to appear and is shown to be correlated with the fraction of cations which are linked through solely edge-sharing structural motifs. A modified effective mean atom coordination number is proposed which allows the appearance of the low frequency feature to be understood in terms of a mean field rigidity percolation threshold. (paper)

  8. Mechanism of eutectic formation upon compaction and its effects on tablet properties

    International Nuclear Information System (INIS)

    Bi, Mingda; Hwang, Sung-Joo; Morris, Kenneth R.

    2003-01-01

    The unique property of a eutectic mixture is a lower melting temperature than that of any of its pure components. What differentiates a eutectic mixture from a simple physical mixture is less well understood. This impedes the ability to anticipate and/or detect unintentional eutectic formation during pharmaceutical tablet manufacturing and any potential negative impact. In this study, a thermodynamic/heat transfer approach was used to explain the mechanism of eutectic formation upon exposure to a physical stress, i.e. compaction, and a differential scanning calorimetric (DSC) method was developed to detect and quantify the amount of eutectic formed in the compacts. Furthermore, the mechanism of eutectic formation upon compaction was tested experimentally by correlating the amount of eutectic formed in tablets with the particle size, compaction force, the estimated intimate contact area between the eutectic-forming materials, calculated tablet tensile strength, and tablet porosity. The effect of the presence of eutectics on tablet properties was also investigated. The results show that intimate contact and mutual solubility between eutectic-forming materials are the necessary and sufficient criteria for eutectic formation upon compaction. The systems of acetaminophen (APAP)/caffeine and APAP/propylphenazone were both shown to exhibit eutectic behavior upon compaction and the extent of formation was dependent upon the amount of intimate contact between eutectic-forming materials. Finally, it was found that eutectic had no negative effect on tablet hardness

  9. Effect of forging process on microstructure, mechanical and corrosion properties of biodegradable Mg-1Ca alloy

    International Nuclear Information System (INIS)

    Harandi, Shervin Eslami; Hasbullah Idris, Mohd; Jafari, Hassan

    2011-01-01

    Research highlights: → Forging temperature demonstrates more pronounced effect compared to forging speed. → Precipitation of Mg 2 Ca phase at grain boundaries accelerates corrosion rate. → Forging process doesn't provide the corrosion resistance required for bone healing. -- Abstract: The performance of Mg-1Ca alloy, a biodegradable metallic material, may be improved by hot working in order that it may be of use in bone implant applications. In this study, Mg-1Ca cast alloy was preheated to different temperatures before undergoing forging process with various forging speeds. Macro- and microstructure of the samples were examined by stereo and scanning electron microscopes (SEM) equipped with energy dispersive X-ray spectroscopy (EDS), respectively. To determine the mechanical properties of the alloy, hardness value and plastic deformation ability of the samples were measured. To investigate the corrosion behaviour of the alloy, immersion and electrochemical tests were performed on the samples in simulated body fluid and the corrosion products were characterized by SEM/EDS. The results showed that increasing forging temperature decreased grain size led to improved hardness value and plastic deformation ability of the alloy, whereas no significant effect was observed by changing forging speed. Moreover, forging at higher temperatures led to an increase in the amount of Mg 2 Ca phase at grain boundaries resulted in higher corrosion rates. It can be concluded that although forging process improved the mechanical properties of the alloy, it does not satisfy the corrosion resistance criteria required for bone healing.

  10. EFFECT OF PLANT PROTEIN ISOLATES ON THE STRUCTURAL – MECHANICAL PROPERTIES OF WHEAT DOUGH

    Directory of Open Access Journals (Sweden)

    Valeriy MAKHYNKO

    2017-06-01

    Full Text Available The results of using isolates of soya, pea and rice flour as well as of dry wheat gluten in the making of bread dough have been presented. Taking into account the high water absorption capacity of these products, effect of the protein isolates on the structural-mechanical properties of the dough has been investigated. On the basis of farinogram curves the additional quantity of water needed to obtain proper structure of dough made from all types of raw materials has been determined. A formula of calculation the additional quantity of water has been proposed. It proves that most quantity of water is needed for dough with isolate of soya protein – 2.3 g per 1 g of added isolate. Isolate of pea protein needs additionally 1.5 g of water, dry wheat gluten – 1.3 g, and isolate of rice protein – 0.9 g of water. The proposed calculation has been checked for mixes with different proportion of raw materials and its effectiveness has been proven. The calculation method was used to determine the additional quantity of water required to obtain wheat dough with necessary structural and mechanical properties.

  11. Effect of strontium on the texture and mechanical properties of extruded Mg–1%Mn alloys

    International Nuclear Information System (INIS)

    Borkar, Hemant; Hoseini, Majid; Pekguleryuz, Mihriban

    2012-01-01

    Highlights: ► Mg–1%Mn and Mg–1%Mn–(0.3–2)Sr alloys were extruded at elevated temperature. ► Strontium additions refine extruded microstructure of M1 alloys. ► Sr additions weaken the basal texture of extruded M1, improve the ductility and reduce the yield asymmetry. ► Texture weakening with increasing strontium additions is the result of particle stimulated nucleation (PSN). - Abstract: Magnesium–manganese, M1, alloy is preferred for extrusion applications due to its extrudability. It is mainly used as a sacrificial anode or as a creep resistant alloy at elevated temperatures in the nuclear industry. Since Mn does not provide a significant strengthening effect, the alloy is not considered for structural applications. The basal texture which forms after extrusion orients the basal planes parallel to the extrusion direction causing anisotropy in mechanical properties. This basal texture, as well as the low strength of the alloy are the main challenges in its widespread applications. In this study, the effect of Sr addition on the texture and mechanical properties of M1 alloy was studied. M1–Sr alloys showed weakened texture by developing random texture components during extrusion. The texture randomisation is attributed to particle stimulated nucleation (PSN) around Mg–Sr intermetallics during recrystallisation. M1–Sr compositions are found to show improved strength and ductility as well as reduced yield asymmetry.

  12. Effects of Heating Rate on the Dynamic Tensile Mechanical Properties of Coal Sandstone during Thermal Treatment

    Directory of Open Access Journals (Sweden)

    Ming Li

    2017-01-01

    Full Text Available The effects of coal layered combustion and the heat injection rate on adjacent rock were examined in the process of underground coal gasification and coal-bed methane mining. Dynamic Brazilian disk tests were conducted on coal sandstone at 800°C and slow cooling from different heating rates by means of a Split Hopkinson Pressure Bar (SHPB test system. It was discovered that thermal conditions had significant effects on the physical and mechanical properties of the sandstone including longitudinal wave velocity, density, and dynamic linear tensile strength; as the heating rates increased, the thermal expansion of the sandstone was enhanced and the damage degree increased. Compared with sandstone at ambient temperature, the fracture process of heat-treated sandstone was more complicated. After thermal treatment, the specimen had a large crack in the center and cracks on both sides caused by loading; the original cracks grew and mineral particle cracks, internal pore geometry, and other defects gradually appeared. With increasing heating rates, the microscopic fracture mode transformed from ductile fracture to subbrittle fracture. It was concluded that changes in the macroscopic mechanical properties of the sandstone were result from changes in the composition and microstructure.

  13. Effect of scandium on the phase composition and mechanical properties of ABM alloys

    Science.gov (United States)

    Molchanova, L. V.

    2010-09-01

    The effect of scandium on the composition and mechanical properties of ABM-1 alloys (Al-30% Be-5% Mg) is studied. The scandium content is varied from 0.1 to 0.5 wt %. It is established that, in the studied part of the Al-Be-Mg-Sc system, an aluminum solid solution (Al) and the ScBe13 compound are in equilibrium with a beryllium solid solution (Be). Magnesium dissolves in both the aluminum component and the ScBe13 compound. The strengthening effect related to the decomposition of the solid solution and the precipitation of Al3Sc cannot be extended to the strengthening of ABM-type alloys. Additions of 0.1-0.15 wt % Sc only weakly improve the mechanical properties of the alloys due to the refinement of beryllium-component grains. At high scandium contents, the strength increases insignificantly due to primary precipitation of ScBe13 and the plasticity decreases simultaneously.

  14. Effect of Thermally Reduced Graphene Oxide on Mechanical Properties of Woven Carbon Fiber/Epoxy Composite

    Directory of Open Access Journals (Sweden)

    Nitai Chandra Adak

    2018-02-01

    Full Text Available Thermally reduced graphene oxide (TRGO was incorporated as a reinforcing filler in the epoxy resin to investigate the effect on the mechanical properties of carbon fiber (CF/epoxy composites. At first, the epoxy matrix was modified by adding different wt % of TRGO from 0.05 to 0.4 wt % followed by the preparation of TRGO/CF/epoxy composites througha vacuum-assisted resin transfer molding process. The prepared TRGO was characterized by using Fourier transform infrared spectroscopy, Raman Spectroscopy and field emission scanning electron microscopy (FE-SEM techniques. It was observed that the wrinkled structure of synthesized TRGO may be helpful to interlock with the epoxy resin and CF.The inter-laminar shear strength, in-plane fracture toughness and impact strength increased by ~67%, 62% and 93% at 0.2 wt % of TRGO loading in the CF/epoxy composites as compared to the CF reinforced epoxy. The mechanical properties of the hybrid composites decreased beyond the 0.2 wt % of TRGO incorporation in the epoxy resin. The fracture surfaces of the hybrid composites were studied by FE-SEM image analysis to investigate the synergistic effect of TRGO in the CF/epoxy composite. This study suggested that TRGO could be used asgood nanofiller to resist the matrix and fiber fracture.

  15. Low dose irradiation effects on DIN 1.4948 mechanical properties

    International Nuclear Information System (INIS)

    Schaaf, B. van der; Vries, M.I. de

    For the SNR 300 the licensing authorities require the determination of the lower boundaries of post-irradiation mechanical properties for DIN 1.4948 parent metal and welded joints. It has been established that with decreasing strain rate the post-irradiation tensile ductility decreases. A transition strain rate has been observed, above which there is no effect of irradiation on ductility. The transition strain rate increases with increasing temperature. Coarse grained heats show lower ultimate tensile strength above 800 K than fine grained heats. There is no significant effect of irradiation on load controlled high cycle fatigue with frequencies of 1 Hz or higher. In low cycle fatigue numbers of cycles to failure decrease with decreasing frequency. Increasing the test temperature reduces the number of cycles to failure even more. The frequency effect is more evident at 823 K. Parent metal has a better fatigue resistance than welded joints in unirradiated and irradiated condition. Creep strength is reduced by irradiation due to loss of ductility. It is shown that with increasing grain size the rupture strength decreases. The ductility of welded joints after irradiation is low, in some cases as low as 0.5% creep strain. After irradiation, tensile, creep and fatigue fracture surfaces show many more intergranular features than in the equivalent unirradiated condition. The promotion of intergranular fracture by irradiation and the consequent degradation of low strain rate mechanical properties is explained by the presence of helium on grain boundaries. Several measures to increase the helium content threshold can be taken, such as grain refinement, homogeneous boron distribution and promotion of helium bubble initiation. In cases where helium embrittlement is encountered, life reduction factors on unirradiated material properties must be applied

  16. Effect of γ-irradiation on the physical and mechanical properties of kefiran biopolymer film.

    Science.gov (United States)

    Shahabi-Ghahfarrokhi, Iman; Khodaiyan, Faramarz; Mousavi, Mohammad; Yousefi, Hossein

    2015-03-01

    In this study, the effect of different γ-ray dosages (3, 6, and 9 kGy) on the functional properties of kefiran biopolymer was investigated. The obtained results showed that increasing γ-ray dosage brought about an increase in the tensile strength of film specimens up to three-times. However, elongation at break, and tensile energy to break of γ-irradiated kefiran films decreased in the wake of increasing γ-ray dosage. γ-Irradiation could improve surface hydrophobicity, sensitivity of kefiran film specimens to water, and water vapor permeability, but yellowness of films increased, simultaneously. XRD spectrum confirmed increased crystallinity of γ-irradiated films. Melting point of films was constant but glass transition temperature decreased drastically at high γ-ray dosage (9 kGy). ATR-FTIR analysis confirmed that γ-ray engendered no changes in chemical functional groups. According to the result, a mechanism was proposed to percept the effects of γ-irradiation on kefiran biopolymer and its role on the functional properties of kefiran film. Hence, the functional properties of kefiran films were depend on the ratio of cross-linkages between polymer chains and produced mono and disaccharide by γ-irradiation. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Effect of special environmental factors exerted on mechanical properties of CFRP

    International Nuclear Information System (INIS)

    Sonoda, Katsumi; Kaneda, Yoshiharu; Tani, Isao; Nakazaki, Koichi; Enomoto, Junzo; Murayama, Kunihiko; Nakano, Norihiko; Hasegawa, Sumiko; Fukuta, Kenji

    1984-01-01

    This research aims at clarifying the behavior of deterioration of composite materials in the special environment of single factor or compound factors, examining the similarity of the acceleration of deterioration to actual environment and extracting the singularity, and establishing the method of evaluating the properties to withstand environmental effect. In this study, the test on the exposure to various special environments, such as thermal shock, low temperature-high temperature cycle fatigue, electron beam irradiation and heat and vacuum, was carried out. An Instron type testing machine was used, and measurement was carried out at room temperature. The results of the examination of the change of properties due to the change of testing condition by thermal shock test, the electron beam irradiation test at 7.5 x 10 8 rad/h, and the examination of the degasing from CFRP by heat and vacuum test are reported. It was found that bending stress loading method was effective as an accelerated test method because the lowering of residual bending fracture strength was accelerated by thermal shock test. The mechanical properties of CFRP did not change by electron beam irradiation up to 5000 Mrad. The degasing from CFRP under heat and vacuum increased with rising temperature. (Kako, I.)

  18. Mechanical properties and osteocompatibility of novel biodegradable alanine based polyphosphazenes: Side group effects.

    Science.gov (United States)

    Sethuraman, Swaminathan; Nair, Lakshmi S; El-Amin, Saadiq; Nguyen, My-Tien; Singh, Anurima; Krogman, Nick; Greish, Yaser E; Allcock, Harry R; Brown, Paul W; Laurencin, Cato T

    2010-06-01

    The versatility of polymers for tissue regeneration lies in the feasibility to modulate the physical and biological properties by varying the side groups grafted to the polymers. Biodegradable polyphosphazenes are high-molecular-weight polymers with alternating nitrogen and phosphorus atoms in the backbone. This study is the first of its kind to systematically investigate the effect of side group structure on the compressive strength of novel biodegradable polyphosphazene based polymers as potential materials for tissue regeneration. The alanine polyphosphazene based polymers, poly(bis(ethyl alanato) phosphazene) (PNEA), poly((50% ethyl alanato) (50% methyl phenoxy) phosphazene) (PNEA(50)mPh(50)), poly((50% ethyl alanato) (50% phenyl phenoxy) phosphazene) (PNEA(50)PhPh(50)) were investigated to demonstrate their mechanical properties and osteocompatibility. Results of mechanical testing studies demonstrated that the nature and the ratio of the pendent groups attached to the polymer backbone play a significant role in determining the mechanical properties of the resulting polymer. The compressive strength of PNEA(50)PhPh(50) was significantly higher than poly(lactide-co-glycolide) (85:15 PLAGA) (p<0.05). Additional studies evaluated the cellular response and gene expression of primary rat osteoblast cells on PNEA, PNEA(50)mPh(50) and PNEA(50)PhPh(50) films as candidates for bone tissue engineering applications. Results of the in vitro osteocompatibility evaluation demonstrated that cells adhere, proliferate, and maintain their phenotype when seeded directly on the surface of PNEA, PNEA(50)mPh(50), and PNEA(50)PhPh(50). Moreover, cells on the surface of the polymers expressed type I collagen, alkaline phosphatase, osteocalcin, osteopontin, and bone sialoprotein, which are characteristic genes for osteoblast maturation, differentiation, and mineralization. Copyright 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  19. Effect of water absorption on the mechanical properties of nanoclay filled recycled cellulose fibre reinforced epoxy hybrid nanocomposites

    KAUST Repository

    Alamri, H.; Low, I.M.

    2013-01-01

    . The addition of nanoclay slightly minimized the effect of moisture on the mechanical properties. SEM images showed that water absorption severely damaged the cellulose fibres and the bonding at fibres-matrix interfaces in wet composites. © 2012 Elsevier Ltd

  20. Effects of consolidation process on microstructure and mechanical properties of commingled glass/polypropylene composites

    International Nuclear Information System (INIS)

    Tufail, M.; Long, A.C.; Rudd, C.D.

    2001-01-01

    The thermal history of a thermoplastic composite material during forming and consolidation is critical to the quality of the component. Attempts to process outside the normal melt region will result in incomplete consolidation and voidage. Clearly then, the preheat phase plays a key role in successful processing. Too low a preheat temperature results in insufficient matrix flow while, if the temperature is increased too much, degradation of the matrix occurs, again resulting in poor quality of the composite. In particular polypropylene has poor chemical (oxidative) resistance, and oxidative degradation reduces the average molecular weight of the materials. If excessive, this can result in a dramatic reduction in mechanical properties. Flat plaques of braided, commingled glass/polypropylene yarn were produced to examine these effects using both isothermal and non-isothermal consolidation. Woven plaques were also produced from commingled yarn in a similar fashion as control samples in order to identify any effects specific to the braiding process. This paper describes the effect of heating and stamping cycles on the properties of these composites, concentrating on the effects of temperature, heating time and compaction rate. (author)

  1. Effect of pulse current parameters on the mechanical and corrosion properties of anodized nanoporous aluminum coatings

    International Nuclear Information System (INIS)

    Mohammadi, Iman; Ahmadi, Shahab; Afshar, Abdollah

    2016-01-01

    In this study, the effects of pulse current parameters on corrosion resistance and mechanical properties of anodized coatings were evaluated. Hardness measurements, polarization and electrochemical impedance spectroscopy tests were employed to investigate the mechanical properties and corrosion behavior of these coatings. Also, field emission scanning electron microscopy (FE-SEM) was used to analyze the surface morphology and microstructure of the coatings. It was found that the properties of anodized coatings were dependent on various parameters, among which, time, temperature and pulse current parameters (current density limit, frequency and duty cycle) were optimized. Analysis of Variance (ANOVA) was conducted in order to optimize the results of designed experiments for predicting the hardness of anodic Al_2O_3 coatings. Experimental results showed that the temperature and the interaction of quadratic behavior of minimum current density with frequency and duty cycle were the most important factors influencing the hardness of these coatings. It was indicated that the highest hardness value of 642 HV was attained at the maximum and minimum current densities of 4.4, 1.27 A/dm"2, respectively, a frequency of 82 Hz, procedure time of 27.2 min, duty cycle of 80.2% and the bath temperature of 13.5 °C. In addition, the FE-SEM micrographs showed that the highest density is obtained through the mentioned optimum conditions. Moreover, the electrochemical tests revealed that the highest polarization resistance obtained at optimum conditions was more than 20 times greater than the other samples. - Highlights: • Electrolyte temperature undesirably influences the hardness of anodized coatings. • Maximum hardness of coatings was evaluated by optimization of effective parameters. • The diameter of alumina nanotube considerably affects hardness of anodized coating. • R_P of the sample formed at optimum condition was at least 20 times more than others. • Porosity is the

  2. Effect of pulse current parameters on the mechanical and corrosion properties of anodized nanoporous aluminum coatings

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadi, Iman, E-mail: imanmohammadi68@gmail.com; Ahmadi, Shahab; Afshar, Abdollah

    2016-11-01

    In this study, the effects of pulse current parameters on corrosion resistance and mechanical properties of anodized coatings were evaluated. Hardness measurements, polarization and electrochemical impedance spectroscopy tests were employed to investigate the mechanical properties and corrosion behavior of these coatings. Also, field emission scanning electron microscopy (FE-SEM) was used to analyze the surface morphology and microstructure of the coatings. It was found that the properties of anodized coatings were dependent on various parameters, among which, time, temperature and pulse current parameters (current density limit, frequency and duty cycle) were optimized. Analysis of Variance (ANOVA) was conducted in order to optimize the results of designed experiments for predicting the hardness of anodic Al{sub 2}O{sub 3} coatings. Experimental results showed that the temperature and the interaction of quadratic behavior of minimum current density with frequency and duty cycle were the most important factors influencing the hardness of these coatings. It was indicated that the highest hardness value of 642 HV was attained at the maximum and minimum current densities of 4.4, 1.27 A/dm{sup 2}, respectively, a frequency of 82 Hz, procedure time of 27.2 min, duty cycle of 80.2% and the bath temperature of 13.5 °C. In addition, the FE-SEM micrographs showed that the highest density is obtained through the mentioned optimum conditions. Moreover, the electrochemical tests revealed that the highest polarization resistance obtained at optimum conditions was more than 20 times greater than the other samples. - Highlights: • Electrolyte temperature undesirably influences the hardness of anodized coatings. • Maximum hardness of coatings was evaluated by optimization of effective parameters. • The diameter of alumina nanotube considerably affects hardness of anodized coating. • R{sub P} of the sample formed at optimum condition was at least 20 times more than others

  3. Effect of Cu addition on the microstructure and mechanical properties of Al–30 wt% Zn alloy

    International Nuclear Information System (INIS)

    Abd El-Rehim, A.F.; Sakr, M.S.; El-Sayed, M.M.; Abd El-Hafez, M.

    2014-01-01

    Highlights: • This paper describes a novel work on the effect of Cu addition on the Al–30 wt% Zn alloy. • The 1 wt% Cu alloy revealed the best hardness of the alloys. • The results indicated two deformation temperature regions (below and above 548 K). - Abstract: The effect of 0.5, 1, 1.5 and 2 wt% Cu addition on the microstructure and mechanical properties of Al–30 wt% Zn alloy has been investigated by stress–strain tests carried out in the temperature range from 508 to 608 K. The work-hardening parameters of the test alloys decreased with increasing the deformation temperature and exhibited discontinuity at 548 K, resulting two deformation temperature regions, the low-temperature region (below 548 K) and high-temperature region (above 548 K). The activation energy of fracture mechanisms has been calculated and found to be 19.6 and 33.2 kJ/mol at the low and high temperature regions respectively. The operating mechanisms of work-hardening of the test alloys were confirmed by the analysis of X-ray diffraction patterns

  4. Effect Of Cooling Rate On Thermal And Mechanical Properties Of Cu-%24.2Mn Alloy

    International Nuclear Information System (INIS)

    Celik, H.

    2010-01-01

    In this research, different heat and mechanical treatments have been applied to the Cu-%24.2Mn and some samples have been obtained from this alloy. On these samples, phase transformations have been formed by thermal and mechanical effect. Morphological, mechanical and crystallographic properties of the phase transformations have been examined by using different physical methods. Austenite phase has been obtained in the samples which have been applied slow and rapid cooling according to the SEM analysis. It has been observed that the grain size obtained by the rapid cooling is smaller than the grain size obtained by the slow cooling. Therefore, it has been concluded that the cooling process differences, changes the grain size of the alloy. Compression stress has been applied to the alloy in order to search the deformation effect on the austenite phase transformation. The structural features of the phase transformations have been examined. Slip lines and martensite structural were observed on the surface of the alloys after the deformation. Changes in phase structure of the alloy are also examined by means of XRD technique.

  5. Effect of Al on Grain Refinement and Mechanical Properties of Mg-3Nd Casting Alloy

    Science.gov (United States)

    Wang, Lei; Feng, Yicheng; Wang, Liping; Chen, Yanhong; Guo, Erjun

    2018-05-01

    The effect of Al on the grain refinement and mechanical properties of as-cast Mg-3Nd alloy was investigated systematically by a series of microstructural analysis, solidification analysis and tensile tests. The results show that Al has an obvious refining effect on the as-cast Mg-3Nd alloy. With increasing Al content, the grain size of the as-cast Mg-3Nd alloy decreases firstly, then increases slightly after the Al content reaching 3 wt.%, and the minimum grain size of the Mg-3Nd alloy is 48 ± 4.0 μm. The refining mechanism can be attributed to the formation of Al2Nd particles, which play an important role in the heterogeneous nucleation. The strength and elongation of the Mg-3Nd alloy refined by Al also increase with increasing Al content and slightly decrease when the Al content is more than 3 wt.%, and the strengthening mechanism is attributed to the grain refinement as well as dispersed intermetallic particles. Furthermore, the microstructural thermal stability of the Mg-3Nd-3Al alloy is higher than that of the Mg-3Nd-0.5Zr alloy. Overall, the Mg-3Nd alloy with Al addition is a novel alloy with wide and potential application prospects.

  6. Effect of cold work and aging on mechanical properties of a copper ...

    Indian Academy of Sciences (India)

    Unknown

    Influence of cold working and aging on the mechanical properties of a ... toughness and ductility in various stages of cold work and aging may include high stress concentration at high ... copper is added to HSLA steels to cause precipitation.

  7. Effect of particle size of granules on some mechanical properties of ...

    African Journals Online (AJOL)

    PRECIOUS

    2009-11-02

    Nov 2, 2009 ... granules on some tablet mechanical properties of paracetamol tablets. Granules ... massing paracetamol powder (200 g) with 20% (w/w) of maize starch mucilage as binder. .... The resulting tablets were stored overnight in a.

  8. Effects of heat treatment on mechanical properties of h13 steel

    Science.gov (United States)

    Guanghua, Yan; Xinmin, Huang; Yanqing, Wang; Xingguo, Qin; Ming, Yang; Zuoming, Chu; Kang, Jin

    2010-12-01

    Heat treatment on the mechanical properties of H13 hot working die steel for die casting is discussed. The H13 steel for die casting was treated by different temperatures of vacuum quenching, tempering, and secondary tempering to investigate its mechanical properties. Strength, plasticity, hardness, and impact toughness of the H13 hot working die steel for die casting were measured. Microstructure, grain size, and carbide particle size after heat treatment have a great impact on the mechanical properties of H13 hot working die steel for die casting. The microstructure of the H13 was analyzed by scanning electron microscopy (SEM) and by a metallographic microscope. It is found that H13 exhibits excellent mechanical properties after vacuum quenching at 1050°C and twice tempering at 600°C.

  9. Effect of polyester fiber reinforcement on the mechanical properties of interim fixed partial dentures

    Directory of Open Access Journals (Sweden)

    N. Gopichander

    2015-10-01

    Conclusion: Within the limitations of this study, polyester fiber reinforcements improved the mechanical properties of heat-polymerized PMMA, cold-polymerized PMMA, and bis-acrylic provisional FPD materials.

  10. Neutron irradiation effects on the mechanical properties of thorium and thorium--carbon alloy

    International Nuclear Information System (INIS)

    Wang, S.C.P.

    1978-04-01

    The effects of neutron exposure to 3.0 x 10 18 neutrons/cm 2 on the mechanical properties of thorium and thorium-carbon alloy are described. Tensile measurements were done at six different test temperatures from 4 0 K to 503 0 K and at two strain rates. Thorium and thorium-carbon alloy are shown to display typical radiation hardening like other face-centered cubic metals. The yield drop phenomenon of the thorium-carbon alloy is unchanged after irradiation. The variation of shear stress and effective shear stress with test temperature was fitted to Seeger's and Fleischer's equations for irradiated and unirradiated thorium and thorium-carbon alloy. Neutron irradiation apparently contributes an athermal component to the yield strength. However, some thermal component is detected in the low temperature range. Strain-rate parameter is increased and activation volume is decreased slightly for both kinds of metal after irradiation

  11. A study on the effect of silicon content on mechanical properties

    International Nuclear Information System (INIS)

    Kwon, C.T.; Nam, T.W.; Lee, S.I.

    1978-01-01

    In Al-Si alloy, the variation of mechanical properties with silicon contents was investigated the silicon content being varied from 5% to 25%, and the effects of additives and refining elements were also studied. The results obtained are as follows: 1) Sodium treatment made the primary silicon crystals refined and spheroidized, and made the matrix structure intensified. The effect of P treatment on refining primary silicon crystals was greater then that of Na. 2) Tensile strength showed the maximum value at near the eutectic composition and was improved considerably by addition of Mg and treatment with Na. 3) The variation of matrix hardness with silicon contents was not perceptible and the hardness was improved by addition of Mg and treatment with Na. (author)

  12. Effect of biocrust: study of mechanical and hydraulic properties and erodibility

    Science.gov (United States)

    Slavík, Martin; Bruthans, Jiří; Schweigstillová, Jana

    2016-04-01

    It is well-known that lichens and other organisms forming crust on soil or rock surface play important role in weathering but may also protect underlying material from fast erosion. So far, there have been only few measurements comparing mechanical or hydraulic properties of biocrust with its subsurface on locked sand and friable sandstones, so the overall effect of the biocrust is not well-understood. Objective of our study is to quantify the effect of the biocrust on mechanical and hydraulic properties of friable sandstone and locked sand of Cretaceous age in six different localities with varying aspect and inclination and age of exposure in sandpit Strelec (Czech Rep.). On the artificial exposures, biocrust developed within last 10-30 years. Beside measurements of mechanical and hydraulic properties, SEM and mercury intrusion porosimetry in crust and subsurface was performed. Drilling resistance technique was found an excellent method to distinguish the biocrust from its subsurface (~3 mm thick biocrust has up to 12 times higher drilling resistance than underlying material). Surface zone with the biocrust has 3 - 25 times higher tensile strength than the subsurface material (1 - 25 kPa). In comparison with the subsurface, the biocrust is considerably less erodible (based on water jet testing). Biocrust saturated hydraulic conductivity is 15 - 240 times lower than the subsurface (6*10 -5 - 1*10 -4 m/s) and its permeability for water vapor is 4 - 9 times lower than subsurface. Presence of the biocrust slows down capillary absorption of water 4 - 25 times. The biocrust is thus forming firm surface which protects underlying material from rain and flowing water erosion and which considerably modifies its hydraulic properties. Material with crust exposed to calcination, leaching by concentrated peroxide and experiments with zymoliase enzyme strongly indicate that major contribution to crust hardening is provided by organic matter. Based on DNA sequencing the crust is

  13. Effects of Stress Concentration on the Mechanical Properties of Carbon Fiber Reinforced Plastic

    OpenAIRE

    Ryo Naito; Mitsuhiro Okayasu; Daisuke Fukuyama

    2015-01-01

    Mechanical properties of conventional CFRP plates with small holes were investigated systematically. Those artificial holes are considered to be rivet connection between CFRP and other materials. The machining holes were employed with different number (n=0-5) and different mode, e.g., parallel (Sample A), 45 degree (Sample B) and perpendicular (Sample C) against the loading direction. To understand the mechanical properties of the CFRP plates clearly, tensile tests and failure analysis were c...

  14. Effect of Silicon Addition on Microstructure and Mechanical Properties of Chromium and Titanium Based Coatings

    Directory of Open Access Journals (Sweden)

    Luis Carlos Ardila-Téllez

    2014-07-01

    Full Text Available The changes in the microstructure, mechanical properties and residual stresses of AlTiN, AlTiSiN, AlCrN and AlCrSiN coatings, has been studied before and after annealing at 900 ºC and 1100 ºC, using scanning and transmission electron microscopy, along with nano-indentation and X-ray diffraction techniques. The As-deposited coatings show a columnar structure, with a crystallite size between 18 nm and 28 nm. Despite the silicon addition, no effect on the crystallite size refinement was observed.However, the addition of silicon increases hardness, elastic modulus and compressive residual stresses. After annealing at 900 ºC, the crystallite size growth and the residual stress relaxes; therefore, the coating hardness decreases. At 1100 ºC, the oxide layers formed in AlTiN and AlTiSiN, which act as protective layers enhancing oxidation resistance; meanwhile, a complete oxidation of AlCrN and AlCrSiN coatings take place. The Titanium based coatings present some superior mechanical properties and oxidation resistance than the chromium based coatings at 900 ºC and 1100 ºC.

  15. Effect of P on Microstructure and Mechanical Properties of Sn-Bi Solder

    Directory of Open Access Journals (Sweden)

    WANG Xiao-jing

    2016-07-01

    Full Text Available Micro alloy metals P or P/Cu/Zn were added into Sn-Bi alloy to investigate the doping effects on microstructure, mechanical property, deformation fracture from the function of P in pure tin. The results show that doping 1%( mass fraction, same as below P to pure tin can improve the strength and stiffness, decrease the plasticity. Only 0.1%P additive degenerates the mechanical property of Sn-Bi alloy, this is related to the existing form of element P in the base metal and the microstructure of the base metal. In Sn base alloy, P is distributed in phase or grain boundaries in the form of Sn-P intermetallic compounds (IMC, restricting the diffusion and shifting of deformation. Therefore, Sn-1P alloy, IMC distributed in beta-tin base plays a role of strengthening in pure tin doped situation, in Sn-Bi alloy instead, enhancing the deformation mismatch under loading becoming the weak spots where cracks may initiate and propagate, and leading to brittle fracture . Finally, addition of P/Zn/Cu simultaneously to Sn-Bi alloy, the doping can optimize the microstructure, improve the strength and enhance the ultimate tensile strength (UTS of Sn-Bi alloys.

  16. Effects of Y2O3 upon mechanical properties of laser coating

    Institute of Scientific and Technical Information of China (English)

    Chi Deng; Yong Wang; Yaping Zhang; Jiacheng Gao

    2005-01-01

    @@ Roles of Y2O3 in mechanical properties of the bioceramic coating by the laser cladding were reported in this paper. The bonding strength of interface between the laser coatings with/without Y2O3 and substrate Ti-6Al-4V (TC4), bending strength, compressive strength, tensile strength, and hardness in these coatings were contrastively tested, and the ceramic-metal interface was observed by scanning electronic microscopy (SEM). These results indicated that the rare earth was the important factor which influenced the mechanical properties of the coating. Y2O3 was adequately dispersed in the melting pool of the laser coating, crystal grain got smaller after the melted coating was cooled, the impurity existing in crystal interface was reduced by chemical reactions, and so the strength was evidently improved. On the other hand, the rare earth could also obviously increase the hole numbers in the coating and decrease the compressive strength. So the effects of the rare earth on the laser coating were intricate and all-purpose.

  17. Effect of Macrosegregation on the Microstructure and Mechanical Properties of a Pressure-Vessel Steel

    Science.gov (United States)

    Yan, Guanghua; Han, Lizhan; Li, Chuanwei; Luo, Xiaomeng; Gu, Jianfeng

    2017-07-01

    Macrosegregation refers to the chemical segregation, which occurs quite commonly in the large forgings such as nuclear reactor pressure vessel. This work assesses the effect of macrosegregation and homogenization treatment on the mechanical properties of a pressure-vessel steel (SA508 Gr.3). It was found that the primary reason for the inhomogeneity of the microstructure was the segregation of Mn, Mo, and Ni. Martensite, and coarse upper bainite with M-A (martensite-austenite) islands have been obtained, respectively, in the positive and negative segregation zone during a simulated quenching process. During tempering, the carbon-rich M-A islands decomposed into a mixture of ferrite and numerous carbides which deteriorated the toughness of the material. The segregation has been substantially minimized by a homogenizing treatment. The results indicate that the material homogenized has a higher impact toughness than the material with segregation, due to the reduction in M-A island in the negative segregation zone. It can be concluded that the microstructure and mechanical properties have been improved remarkably by means of homogenization treatment.

  18. EFFECTS OF MO ADDITION ON THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF CAST MICROALLOYED STEEL

    Directory of Open Access Journals (Sweden)

    H. Torkamani

    2017-09-01

    Full Text Available In industry, the cost of production is an important factor and it is preferred to use conventional and low cost procedures for producing the parts. Heat treatment cycles and alloying additions are the key factors affecting the microstructure and mechanical properties of the cast steels. In this study an attempt was made to evaluate the influence of minor Mo addition on the microstructure and mechanical properties of conventionally heat treated cast micro-alloyed steels. The results of Jominy and dilatometry tests and also microstructural examinations revealed that Mo could effectively increase the hardenability of the investigated steel and change the microstructure features of the air-cooled samples. Acicular microstructure was the consequence of increasing the hardenability in Mo-added steel. Besides, it was found that Mo could greatly affect the isothermal bainitic transformation and higher fraction of martensite after cooling (from isothermal temperature was due to the Mo addition. The results of impact test indicated that the microstructure obtained in air-cooled Mo-added steel led to better impact toughness (28J in comparison with the base steel (23J. Moreover, Mo-added steel possessed higher hardness (291HV, yield (524MPa and tensile (1108MPa strengths compared to the base one.

  19. Effects of sintering atmosphere on the physical and mechanical properties of modified BOF slag glass

    Science.gov (United States)

    Dai, Wen-bin; Li, Yu; Cang, Da-qiang; Zhou, Yuan-yuan; Fan, Yong

    2014-05-01

    This study proposes an efficient way to utilize all the chemical components of the basic oxygen furnace (BOF) slag to prepare high value-added glass-ceramics. A molten modified BOF slag was converted from the melting BOF slag by reducing it and separating out iron component in it, and the modified BOF slag was then quenched in water to form glasses with different basicities. The glasses were subsequently sintered in the temperature range of 600-1000°C in air or nitrogen atmosphere for 1 h. The effects of different atmospheres on the physical and mechanical properties of sintered samples were studied by using differential scanning calorimetry (DSC), X-ray diffraction (XRD) and scanning electron microscopy (SEM) and by conducting experiment on evaluating the sintering shrinkage, water absorption and bulk density. It is found that the kinetics of the sintering process is significantly affected by sintering atmosphere. In particular, compared with sintering in air atmosphere, sintering in N2 atmosphere promotes the synergistic growth of pyroxene and melilite crystalline phases, which can contribute to better mechanical properties and denser microstructure.

  20. Effect of fiber surface state on mechanical properties of Cf/Si-O-C composites

    International Nuclear Information System (INIS)

    Wang Song; Chen Zhaohui; Ma Qingsong; Hu Haifeng; Zheng Wenwei

    2005-01-01

    Three-dimensional braided carbon fiber reinforced silicon oxycarbide composites (3D-B C f /Si-O-C) were fabricated via a polysiloxane infiltration and pyrolysis route. The effects of fiber surface state on microstructure and mechanical properties of C f /Si-O-C composites were investigated. The change of carbon fiber surface state was achieved via heat treatment in vacuum. The results showed that heat treatment decreased carbon fiber surface activity due to the decrease of the amount of oxygen and nitrogen atoms. The C f /Si-O-C composites fabricated from the carbon fiber with low surface activity had excellent mechanical properties, which resulted from perfect interfacial bonding and good in situ fiber strength. The flexural strength and fracture toughness of the C f /Si-O-C composites from the treated fiber were 534 MPa and 23.4 MPa m 1/2 , respectively, which were about 7 and 11 times more than those of the composites from the as-received carbon fiber, respectively

  1. Effect of nylon fiber on mechanical properties of cement based mortar

    Science.gov (United States)

    Hanif, I. M.; Syuhaili, M. R. Noor; Hasmori, M. F.; Shahmi, S. M.

    2017-11-01

    An investigation has been carried out to study the effect of nylon fiber on the mechanical properties of cement based mortar after receiving large quantities of nylon waste. Subsequently, this research was conducted to compare the compressive, tensile and flexural strength of normal cement based mortar with nylon fiber cement based mortar. All samples using constant water-cement ratio of 0.63 and three different percentages of nylon fiber were added in the mixture during the samples preparation period which consists of 0.5%, 1.5% and 2.5% by total weight of cement based mortar. The results obtained with different nylon percentage marked an increases in compressive strength (up to 17%), tensile strength (up to 21%) and flexural strength (up to 13%) when compared with control cement based mortar samples. Therefore, the results obtained from this study shows that by using nylon fiber as additive material can improve the mechanical properties of the cement based mortar and at the same time produce a good sustainable product that can protects and conserve the marine environment.

  2. Mechanical properties of rubberwood oriented strand lumber (OSL: The effect of strand length

    Directory of Open Access Journals (Sweden)

    Buhnnum Kyokong

    2005-09-01

    Full Text Available Effect of strand length on mechanical properties (tension, compression and bending of oriented strand lumber (OSL made of rubberwood (Hevea brasiliensis Muell. Arg. was reported. Three strand lengths of 50 mm, 100 mm, and 150 mm with 1 mm thickness and 15 mm width were used. The strands were mixed with 5% pMDI glue (weight basis in a tumble mixer. The OSL specimens were formed by hot pressing process of unidirectionally aligned strands. Average specific gravity and moisture content were 0.76 and 8.34%, respectively. Tension and compression tests were carried out for directions both parallel and perpendicular to grain while bending test was performed only in parallel direction. Ultimate stresses and moduli of elasticity were examined from the stress-strain curves. It was found that for the parallel-to-grain direction, the longer strand OSL gave higher strength. The role of the strand length did not appear for the direction normal to the grain. The relationship between the mechanical properties of OSL and strand length was well described by the modified Hankinson formula.

  3. Effect of G-Coat Plus on the mechanical properties of glass-ionomer cements.

    Science.gov (United States)

    Bagheri, R; Taha, N A; Azar, M R; Burrow, M F

    2013-12-01

    Although various mechanical properties of tooth-coloured materials have been described, little data have been published on the effect of ageing and G-Coat Plus on the hardness and strength of the glass-ionomer cements (GICs). Specimens were prepared from one polyacid-modified resin composite (PAMRC; Freedom, SDI), one resin-modified glass-ionomer cement; (RM-GIC; Fuji II LC, GC), and one conventional glass-ionomer cement; (GIC; Fuji IX, GC). GIC and RM-GIC were tested both with and without applying G-Coat Plus (GC). Specimens were conditioned in 37 °C distilled water for either 24 hours, four and eight weeks. Half the specimens were subjected to a shear punch test using a universal testing machine; the remaining half was subjected to Vickers Hardness test. Data analysis showed that the hardness and shear punch values were material dependent. The hardness and shear punch of the PAMRC was the highest and GIC the lowest. Applying the G-Coat Plus was associated with a significant decrease in the hardness of the materials but increase in the shear punch strength after four and eight weeks. The mechanical properties of the restorative materials were affected by applying G-Coat Plus and distilled water immersion over time. The PAMRC was significantly stronger and harder than the RM-GIC or GIC. © 2013 Australian Dental Association.

  4. Modelling the Size Effects on the Mechanical Properties of Micro/Nano Structures

    Directory of Open Access Journals (Sweden)

    Amir Musa Abazari

    2015-11-01

    Full Text Available Experiments on micro- and nano-mechanical systems (M/NEMS have shown that their behavior under bending loads departs in many cases from the classical predictions using Euler-Bernoulli theory and Hooke’s law. This anomalous response has usually been seen as a dependence of the material properties on the size of the structure, in particular thickness. A theoretical model that allows for quantitative understanding and prediction of this size effect is important for the design of M/NEMS. In this paper, we summarize and analyze the five theories that can be found in the literature: Grain Boundary Theory (GBT, Surface Stress Theory (SST, Residual Stress Theory (RST, Couple Stress Theory (CST and Surface Elasticity Theory (SET. By comparing these theories with experimental data we propose a simplified model combination of CST and SET that properly fits all considered cases, therefore delivering a simple (two parameters model that can be used to predict the mechanical properties at the nanoscale.

  5. Effect of temperature on physical and mechanical properties of concrete containing silica fume

    International Nuclear Information System (INIS)

    Saad, M.; Hanna, G.B.; Abo-El-Enein, S.A.; Kotkata, M.F.

    1996-01-01

    Heat-resistant materials are usually used for structural purposes. The need for such building materials is particularly important in the chemical and metallurgical industries and for the thermal shieldings of nuclear power plants. Thus the effect of high temperatures on physical and mechanical properties of concrete was investigated. In this study ordinary Portland cement has been partially replaced by ratios of silica fume. The heat treatment temperature varied from 100 to 600 C by increments of 100 C for three hours without any load. Concrete specimens were treated at each temperature level. The specimens were heated under the same condition for each temperature level. Comparison between physical and mechanical properties during heat treatment were investigated. All specimens were moist-cured for 28 days after casting. Tests were carried out on specimens cooled slowly to room temperature after heating. Results of this investigation indicated that the replacement of ordinary Portland cement by 10% silica fume by weight improved the compressive strength by about 64.6%, but replacement of ordinary Portland cement by silica fume by ratios 20 and 30% improved the compressive strength by only 28% at 600 C. This could be attributed to the additional tobermorite gel (CSH phase) which formed due to the reaction of silica fume with Ca(OH) 2

  6. Effect of nano-clay on mechanical and thermal properties of geopolymer

    Directory of Open Access Journals (Sweden)

    H. Assaedi

    2016-03-01

    Full Text Available The effect of nano-clay platelets (Cloisite 30B on the mechanical and thermal properties of fly ash geopolymer has been investigated in this paper. The nano-clay platelets are added to reinforce the geopolymer at loadings of 1.0%, 2.0%, and 3.0% by weight. The phase composition and microstructure of geopolymer nano-composites are also investigated using X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FTIR and scanning electron microscope (SEM techniques. Results show that the mechanical properties of geopolymer nano-composites are improved due to addition of nano-clay. It is found that the addition of 2.0 wt% nano-clay decreases the porosity and increases the nano-composite's resistance to water absorption significantly. The optimum 2.0 wt% nano-clay addition exhibited the highest flexural and compressive strengths, flexural modulus and hardness. The microstructural analysis results indicate that the nano-clay behaves not only as a filler to improve the microstructure, but also as an activator to facilitate the geopolymeric reaction. The geopolymer nano-composite also exhibited better thermal stability than its counterpart pure geopolymer.

  7. Effect of multiple repairs in girth welds of pipelines on the mechanical properties

    International Nuclear Information System (INIS)

    Vega, O.E.; Hallen, J.M.; Villagomez, A.; Contreras, A.

    2008-01-01

    This work presents the results of multiple weld repairs in the same area in seamless API X-52 microalloyed steel pipe. Four conditions of shielded metal arc welding repairs and one as-welded specimen of the girth weld were characterized to determine changes in the microstructure, grain size in the heat affected zone, and to evaluate their effect on the mechanical properties of the weld joints. The mechanical properties by means of tension tests, Charpy-V impact resistance and Vickers hardness of the welds were analyzed. The results indicate that significant changes are not generated in the microstructural constituents of the heat affected zone. Grain growth in the heat affected zone at the specimen mid-thickness with the number of repairs was observed. Tensile strength of the weld joints meets the requirement of the API 1104 standard even after the fourth weld repair. Significant reduction in Charpy-V impact resistance with the number of weld repairs was found when the notch location was in the intersection of the fusion line with the specimen mid-thickness. A significant increase in the Vickers hardness of the heat affected zone occurred after the first repair and a gradual decrease in the Vickers hardness occurred as the number of repairs increases

  8. Effect of ZnO nanoparticles to mechanical properties of thixoformed Mg-Al-Zn alloy

    Science.gov (United States)

    Kusharjanto; Soepriyanto, Syoni; Ardian Korda, Akhmad; Adi Dwiwanto, Supono

    2018-03-01

    Magnesium alloys are lightweight metallic materials with low mechanical properties. Therefore, in order to meet the requirements in various industrial sector applications such as automotive, aerospace and electronic frame, improvement strength and ductility is required. The purpose of this research is to investigate the effect of adding ZnO nanoparticles to changes in microstructure, hardness, mechanical properties regarding with yield and ultimate strength. In this research, the molten Mg-Al-Zn alloy is added ZnO nanoparticles with a various range of 0, 1; 3 and 5 wt% and then cooling in the room temperature. Futhermore, Mg-Al-Zn-ZnO is heated at a temperature of 530 °C (in the semi-solid temperature range 470 °C–595 °C or 53% solid fraction) and then thixoforming process is performed. The characterization results of the thixoforming product show that, the microstructure is globular in shape with maximum hardness value of 107.14 VHN, the yield strength of 214.87 MPa, and the ultimate tensile strength of 311.25 MPa in 5 wt% ZnO nanoparticles.

  9. Effects of heat treatment conditions on microstructure and mechanical properties of AISI 420 steel

    Energy Technology Data Exchange (ETDEWEB)

    Scheuer, C.J.; Fraga, R.A.; Cardoso, R.P.; Brunatto, S.F. [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Departamento de Engenharia Mecanica. Grupo de Tecnologia de Fabricacao Assistida por Plasma e Metalurgia do Po

    2014-07-01

    The cycle control of heat treatments, on the quenching and tempering operation of AISI 420 stainless steel, is essential for improved material performance. The adequate choice of heat treatment parameters, can lead an optimization on its mechanical properties and corrosion resistance. Thus, this paper aims to investigate the effects of quenchants medium, and austenitizing and tempering temperatures, on the microstructure and mechanical properties of AISI 420 steel. Different heat treatments cycles were studied: 1) samples were austenitized at 1050°C and water, oil and air quenched; 2) samples were austenitized at range temperatures of 950-1050°C and oil quenched; and 3) as-quenched samples were tempering at range temperatures of 400-500°C. Treated samples were characterized by optical microscopy, X-ray diffractometry and hardness measurements. The samples hardness increases with increasing cooling rate (water > oil > air quenched). Water quenched samples presented crack after cooling to room temperature. Samples hardness also increases with austenitizing temperature increasing, and decreases with increasing tempering temperature. (author)

  10. Effect of chemical treatment of Kevlar fibers on mechanical interfacial properties of composites.

    Science.gov (United States)

    Park, Soo-Jin; Seo, Min-Kang; Ma, Tae-Jun; Lee, Douk-Rae

    2002-08-01

    In this work, the effects of chemical treatment on Kevlar 29 fibers have been studied in a composite system. The surface characteristics of Kevlar 29 fibers were characterized by pH, acid-base value, X-ray photoelectron spectroscopy (XPS), and FT-IR. The mechanical interfacial properties of the final composites were studied by interlaminar shear strength (ILSS), critical stress intensity factor (K(IC)), and specific fracture energy (G(IC)). Also, impact properties of the composites were investigated in the context of differentiating between initiation and propagation energies and ductile index (DI) along with maximum force and total energy. As a result, it was found that chemical treatment with phosphoric acid solution significantly affected the degree of adhesion at interfaces between fibers and resin matrix, resulting in improved mechanical interfacial strength in the composites. This was probably due to the presence of chemical polar groups on Kevlar surfaces, leading to an increment of interfacial binding force between fibers and matrix in a composite system.

  11. Effect of thermal shock on mechanical properties of injection-molded thermoplastic denture base resins.

    Science.gov (United States)

    Takahashi, Yutaka; Hamanaka, Ippei; Shimizu, Hiroshi

    2012-07-01

    This study investigated the effect of thermal shock on the mechanical properties of injection-molded thermoplastic denture base resins. Four thermoplastic resins (two polyamides, one polyethylene terephthalate, one polycarbonate) and, as a control, a conventional heat-polymerized polymethyl methacrylate (PMMA), were tested. Specimens of each denture base material were fabricated according to ISO 1567 and were either thermocycled or not thermocycled (n = 10). The flexural strength at the proportional limit (FS-PL), the elastic modulus and the Charpy impact strength of the denture base materials were estimated. Thermocycling significantly decreased the FS-PL of one of the polyamides and the PMMA and it significantly increased the FS-PL of one of the polyamides. In addition, thermocycling significantly decreased the elastic modulus of one of the polyamides and significantly increased the elastic moduli of one of the polyamides, the polyethylene terephthalate, polycarbonate and PMMA. Thermocycling significantly decreased the impact strength of one of the polyamides and the polycarbonate. The mechanical properties of injection-molded thermoplastic denture base resins changed after themocycling.

  12. Effects of postpolymerization microwave irradiation on provisional dental acrylics: physical and mechanical properties.

    Science.gov (United States)

    Ozkomur, Ahmet; Fortes, Carmen Beatriz Borges

    2016-07-26

    This study aimed to evaluate the effects of microwave irradiation on the physical and mechanical properties of poly(methyl methacrylate) (PMMA) provisional resins. Twenty bars and 20 disc-shaped specimens were fabricated for each selected provisional restorative material (Dencor and Duralay). Test groups were subjected to microwave irradiation (3 minutes at 600 W) after polymerization. Bar specimens were subjected to a flexural strength test. Disc-shaped specimens were used to evaluate microhardness. Backscattered Raman spectroscopy was employed for each group to define the degree of conversion of the monomer/polymer. The frequency bands corresponding to C = C and C = O groups were used to determine the conversion of methyl methacrylate (MMA) monomers into polymers. Glass transition temperature was determined using a differential scanning calorimeter. Microwave irradiation of both tested autopolymerizing PMMA provisional materials resulted in a statistically significant increase in microhardness, degree of conversion and glass transition temperature values. Also, the results demonstrated a significant increase in flexural strength after postpolymerization microwave irradiation for the Dencor specimens. It is concluded that mechanical and physical properties are positively influenced by microwave irradiation.

  13. Effect of the interface on the mechanical properties and thermal conductivity of bismuth telluride films

    Science.gov (United States)

    Lai, Tang-Yu; Wang, Kuan-Yu; Fang, Te-Hua; Huang, Chao-Chun

    2018-02-01

    Bismuth telluride (Bi2Te3) is a type of thermoelectric material used for energy generation that does not cause pollution. Increasing the thermoelectric conversion efficiency (ZT) is one of the most important steps in the development of thermoelectric components. In this study, we use molecular dynamics to investigate the mechanical properties and thermal conductivity of quintuple layers of Bi2Te3 nanofilms with different atomic arrangements at the interface and study the effects of varying layers, angles, and grain boundaries. The results indicate that the Bi2Te3 nanofilm perfect substrate has the ideal Young’s modulus and thermal conductivity, and the maximum yield stress is observed for a thickness of ∼90 Å. As the interface changed, the structural disorder of atomic arrangement affected the mechanical properties; moreover, the phonons encounter lattice disordered atomic region will produce scattering reduce heat conduction. The results of this investigation are helpful for the application of Bi2Te3 nanofilms as thermoelectric materials.

  14. Effect of nanoclay on durability and mechanical properties of flax fabric reinforced geopolymer composites

    Directory of Open Access Journals (Sweden)

    H. Assaedi

    2017-03-01

    Full Text Available The main concern of using natural fibres as reinforcement in geopolymer composites is the durability of the fibres. Geopolymers are alkaline in nature because of the alkaline solution that is required for activating the geopolymer reaction. The alkalinity of the matrix, however, is the key reason of the degradation of natural fibres. The purpose of this study is to determine the effect of nanoclay (NC loading on the mechanical properties and durability of flax fabric (FF reinforced geopolymer composites. The durability of composites after 4 and 32 weeks at ambient temperature is presented. The microstructure of geopolymer matrices was investigated using X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FTIR and scanning electron microscopy (SEM. The results showed that the incorporation of NC has a positive impact on the physical properties, mechanical performance, and durability of FF reinforced geopolymer composites. The presence of NC has a positive impact through accelerating the geopolymerization, reducing the alkalinity of the system and increasing the geopolymer gel.

  15. Effect of 60Co radiation-induced grafting of methyl methacrylate on mechanical properties of bamboo

    International Nuclear Information System (INIS)

    Zhang Hao; Zhou Liang; Liu Shengquan; Qian Liangcun; Fei Benhua; Jiang Zehui

    2011-01-01

    In order to investigate the effect of radiation grafting on mechanical properties of bamboo, the original and carbonized bamboo soaked with monomer MMA were radiation grafted by 60 Co γ rays with the doses of 60-220 kGy. The results showed that compared with original blanks, treated with MMA and irradiated with the dose of 180 kGy the specific gravity, bending strength modulus of elasticity of original bamboo increased by 6.7%, 4.4%, and 28%, meanwhile its oven-dried radial, tangential and volumetric shrinkage decreased by 38.9%, 47.4%, and 32.9%, respectively. What is more, treated with MMA and irradiated with the doses of 140 kGy the specific gravity and modulus of elasticity of carbonized bamboo increased by 6.8% and 20%, while its oven-dried radial, tangential, volumetric shrinkage decreased by 11%, 4.6% and 12%, respectively. The study reveals that mechanical properties of original and carbonized bamboo can be enhanced by radiation grafting copolymerization with suitable absorbed doses, which may be valuable for the further research of developing new bamboo plastic composites. (authors)

  16. The Effect of Ultrasonic Waves on Sugar Extraction and Mechanical Properties of Sugar Beet

    Directory of Open Access Journals (Sweden)

    K Hedayati

    2013-09-01

    Full Text Available Sugar, which can be extracted from sugar cane and sugar beet, is one of the most important ingredients of food. Conducting more research to increase the extraction efficiency of sugar is necessary due to high production of sugar beet and its numerous processing units in northern Khorasan province. In this research, the effect of temperature, time and the frequency of ultrasonic waves on mechanical properties of sugar beet and its extraction rate of sugar in moisture content of 75% were studied. In this regard, an ultrasonic bath in laboratory scale was used. The studied parameters and their levels were frequency in three levels (zero, 25 and 45 KHz, temperature in three levels (25, 50 and 70 ° C and the imposed time of ultrasonic waves in three levels (10, 20 and 30 min. Samples were prepared using planned experiments and the results were compared with control sugar beet samples. A Saccharimeter was used to measure the concenteration of sugar in samples. Two different types of probe including semi-spherical end and the other one with sharpened edges were used to measure mechanical properties. The studied parameters of frequency, temperature and time showed significant effect on sugar extraction and their resulted effect in optimized levels revealed up to 56% increase in sugar extraction compared with control samples. The obtained values of elastic modulus and shear modulus showed a decreasing trend. The obtained values of total energy of rupture, the total energy of shear, the maximum force of rupture, and the yield point of rupture showed an increasing trend. The frequency had no significant effect on the yield point of rupture and shear force.

  17. Mechanical and barrier properties of maize starch-gelatin composite films: effects of amylose content.

    Science.gov (United States)

    Wang, Kun; Wang, Wenhang; Ye, Ran; Xiao, Jingdong; Liu, Yaowei; Ding, Junsheng; Zhang, Shaojing; Liu, Anjun

    2017-08-01

    In order to obtain new reinforcing bio-fillers to improve the physicochemical properties of gelatin-based films, three types of maize starch, waxy maize starch (Ap), normal starch (Ns) and high-amylose starch (Al), were incorporated into gelatin film and the resulting film properties were investigated, focusing on the impact of amylose content. The thickness, opacity and roughness of gelatin film increased depending on the amylose content along with the starch concentration. The effects of the three starches on the mechanical properties of gelatin film were governed by amylose content, starch concentration as well as environmental relative humidity (RH). At 75% RH, the presence of Al and Ns in the gelatin matrix increased the film strength but decreased its elongation, while Ap exhibited an inverse effect. Starch addition decreased the oxygen permeability of the film, with the lowest value at 20% Al and Ns. All starches, notably at 30% content, led to a decrease in the water vapor permeability of the film at 90% RH, especially Ns starch. Furthermore, the starches improved the thermal stability of the film to some extent. Fourier transform infrared spectra indicated that some weak intermolecular interactions such as hydrogen bonding occurred between gelatin and starch. Moreover, a high degree of B-type crystallinity of starch was characterized in Gel-Al film by X-ray diffraction. Tailoring the properties of gelatin film by the incorporation of different types of maize starch provides the potential to extend its applications in edible food packaging. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  18. Irradiation effects on the mechanical properties of aluminium and the structural integrity of aluminium reactor components

    International Nuclear Information System (INIS)

    Harrison, R.P.; McDonald, N.R.; Mitchell, D.R.G.; Hellier, A.K.; Stathers, P.A.; Carr, D.G.; Ripley, M.I.

    2000-01-01

    The results of micro-structural and mechanical property studies on aluminum after being exposed to large fluences of neutrons are presented. These property changes are of importance in determining the structural integrity of the Australian HIFAR reactor aluminium tank, which in turn determines the lifetime of the reactor. (author)

  19. Autoclaving and clinical recycling: Effects on mechanical properties of orthodontic wires

    Directory of Open Access Journals (Sweden)

    M Oshagh

    2012-01-01

    Conclusion: Although recycle wires were softer than those of control group, relatively small differences and also various properties of available wires have obscured the clinical predictability of their application. There is seemingly no problem in terms of mechanical properties to recycle orthodontic wires.

  20. Effect of radiation on disinfection and mechanical properties of Korean traditional paper, Hanji

    Science.gov (United States)

    Choi, Jong-il; Chung, Yong Jae; Kang, Dai Ill; Lee, Kyu Shik; Lee, Ju-Woon

    2012-08-01

    Fumigants, including methyl bromide and ethylene oxide, are generally used for the preservation of the Korean cultural heritage, especially paper products like letters and books. However, the use of fumigants is banned because of their harmful effects on humans and the environment. Gamma irradiation is being considered as an alternative for the sterilization of insects and fungi in organic products. Therefore, the purpose of this study was to investigate the sterilization effects of radiation and its effect on the mechanical properties of the Korean traditional paper—Hanji. Treatment doses of 9 kGy and 8 kGy of gamma irradiation inactivated 5 log units of Aspergillus niger and Bacillus cereus spores inoculated on Hanji, respectively. The gamma irradiations up to an absorbed dose of 50 kGy resulted in no significant changes in the tensile strength, bursting strength, and appearance of Hanji. These results confirmed that radiation treatment disinfects the Korean traditional paper efficiently without changing its properties and that this treatment could be used to prevent the damage of Korean ancient archives by molds and fungi.

  1. Drying and storage effects on poly(ethylene glycol) hydrogel mechanical properties and bioactivity.

    Science.gov (United States)

    Luong, P T; Browning, M B; Bixler, R S; Cosgriff-Hernandez, E

    2014-09-01

    Hydrogels based on poly(ethylene glycol) (PEG) are increasingly used in biomedical applications because of their ability to control cell-material interactions by tuning hydrogel physical and biological properties. Evaluation of stability after drying and storage are critical in creating an off-the-shelf biomaterial that functions in vivo according to original specifications. However, there has not been a study that systematically investigates the effects of different drying conditions on hydrogel compositional variables. In the first part of this study, PEG-diacrylate hydrogels underwent common processing procedures (vacuum-drying, lyophilizing, hydrating then vacuum-drying), and the effect of this processing on the mechanical properties and swelling ratios was measured. Significant changes in compressive modulus, tensile modulus, and swelling ratio only occurred for select processed hydrogels. No consistent trends were observed after processing for any of the formulations tested. The effect of storage conditions on cell adhesion and spreading on collagen- and streptococcal collagen-like protein (Scl2-2)-PEG-diacrylamide hydrogels was then evaluated to characterize bioactivity retention after storage. Dry storage conditions preserved bioactivity after 6 weeks of storage; whereas, storage in PBS significantly reduced bioactivity. This loss of bioactivity was attributed to ester hydrolysis of the protein linker, acrylate-PEG-N-hydroxysuccinimide. These studies demonstrate that these processing methods and dry storage conditions may be used to prepare bioactive PEG hydrogel scaffolds with recoverable functionality after storage. © 2013 Wiley Periodicals, Inc.

  2. The effect of endodontic regeneration medicaments on mechanical properties of radicular dentin

    Science.gov (United States)

    Yassen, Ghaeth H.

    Endodontic regeneration treatment of necrotic immature teeth has gained popularity in recent years. The approach suggests a biological alternative to induce a continuous root development. In this project, three in vitro experiments were conducted to investigate the effect of three medicaments used in endodontic regeneration on mechanical properties and chemical structure of radicular dentin. In the first experiment, we investigated longitudinally the effect of medicaments on the indentation properties of the root canal surface of immature teeth using a novel BioDent reference point indenter. A significant difference in the majority of indentation parameters between all groups was found after one-week and one-month application of medicaments (p double antibiotic paste (DAP) > control > calcium hydroxide [Ca(OH)2]. The four-week exposure of dentin to TAP and DAP caused 43% and 31% increase in total indentation distance outcome, respectively. In the second experiment, we investigated longitudinally the effect of medicaments on the chemical structure of immature radicular dentin by measuring the phosphate/amide I ratios of dentin using Attenuated Total Reflection Fourier Transform Infrared Spectroscopy. Phosphate/amide I ratios were significantly different between the four groups after one week, two weeks and four week application of medicaments (p untreated dentin > DAP-treated dentin > TAP-treated dentin. In the third experiment, we investigated longitudinally the effect of medicaments on root fracture resistance and microhardness of radicular dentin. For the microhardness, the two-way interaction between group and time was significant (pmedicaments caused significant decrease in fracture resistance ranging between 19%-30% after three month application compared to one week application. The three medicaments used in endodontic regeneration caused significant change in the chemical integrity of the superficial radicular dentin and significantly affected the indentation

  3. Effect of Hot Rolling on the Microstructure and Mechanical Properties of Nitrogen Alloyed Austenitic Stainless Steel

    Science.gov (United States)

    Chenna Krishna, S.; Karthick, N. K.; Jha, Abhay K.; Pant, Bhanu; Cherian, Roy M.

    2018-05-01

    In the present investigation, the effect of multi-pass hot rolling in the temperature range of 700-1000 °C on the microstructure and mechanical properties of nitrogen alloyed austenitic stainless steel was studied with the aid of optical microscopy, tensile testing and x-ray diffraction measurements. The microstructural changes that occurred in the hot rolled specimens were elongation of grains in rolling direction, nucleation of new grains at the grain boundaries of elongated grains and growth of nucleated grains to form fully recrystallized grains. Elongated grains formed at lower rolling temperature (700-800 °C) due to inadequate strain/temperature for the initiation of dynamic recrystallization. At higher rolling temperature (900-1000 °C), fine grains formed due to dynamic recrystallization. Tensile properties showed strong dependency on the rolling temperature. Tensile strength increased with the decrease in the rolling temperature at the cost of ductility. Maximum strength was observed in samples hot rolled at 700 °C with yield strength of 917 MPa and ductility of 25%. This variation in the tensile properties with the rolling temperature is attributed to changes in the dislocation density and grain structure. The estimated yield strength from the dislocation density, solid solution and grain boundary strengthening closely matched with experimentally determined yield strength confirming the role of dislocation density and grain size in the strengthening.

  4. Chemical structure, network topology, and porosity effects on the mechanical properties of Zeolitic Imidazolate Frameworks

    OpenAIRE

    Tan, J. C.; Bennett, T. D.; Cheetham, A. K.

    2010-01-01

    The mechanical properties of seven zeolitic imidazolate frameworks (ZIFs) based on five unique network topologies have been systematically characterized by single-crystal nanoindentation studies. We demonstrate that the elastic properties of ZIF crystal structures are strongly correlated to the framework density and the underlying porosity. For the systems considered here, the elastic modulus was found to range from 3 to 10 GPa, whereas the hardness property lies between 300 MPa and 1.1 GPa. ...

  5. Effect of layering sequence and chemical treatment on the mechanical properties of woven kenaf–aramid hybrid laminated composites

    International Nuclear Information System (INIS)

    Yahaya, R.; Sapuan, S.M.; Jawaid, M.; Leman, Z.; Zainudin, E.S.

    2015-01-01

    Highlights: • The mechanical properties of woven kenaf/Kevlar hybrid composites were analysed. • The layering sequences affect the mechanical properties of hybrid composites. • Treated kenaf improves the mechanical properties of hybrid composites. - Abstract: This work aims to evaluate the effect of layering sequence and chemical treatment on mechanical properties of woven kenaf–Kevlar composites. Woven kenaf–aramid hybrid laminated composites fabricated through hand lay-up techniques by arranging woven kenaf and Kevlar fabrics in different layering sequences and by using treated kenaf mat. To evaluate the effect of chemical treatment on hybrid composites, the woven kenaf mat was treated with 6% sodium hydroxide (NaOH) diluted solution and compared mechanical properties with untreated kenaf hybrid composites. Results shows that the tensile properties of hybrid composites improved in 3-layer composites compared to 4-layer composites. Hybrid composite with Kevlar as outer layers display a better mechanical properties as compared to other hybrid composites. Tensile and flexural properties of treated hybrid composites are better than non-treated hybrid composites. The fractured surface of hybrid composites was investigated by scanning electron microscopy. This study is a part of exploration of potential application of the hybrid composite in high velocity impact application

  6. Thermal and irradiation effects on high-temperature mechanical properties of materials for SCWR fuel cladding

    International Nuclear Information System (INIS)

    Kano, F.; Tsuchiya, Y.; Oka, K.

    2009-01-01

    The thermal and irradiation effects on high-temperature mechanical properties are examined for candidate alloys for fuel cladding of supercritical water-cooled reactors (SCRWs). JMTR (Japan Materials Testing Reactor) and Experimental Fast Reactor JOYO were utilized for neutron irradiation tests, considering their fluence and temperature. Irradiation was performed with JMTR at 600degC up to 4x10 24 n/m 2 and with JOYO at 600degC and 700degC up to 6x10 25 n/m 2 . Tensile test, creep test and hardness measurement were carried out for high-temperature mechanical properties. Based on the uniaxial creep test, the extrapolation curves were drawn with time-temperature relationships utilizing the Larson and Miller Parameter. Several candidate alloys are expected to satisfy the design requirement from the estimation of the creep rupture stress for 50000 hours. Comparing the creep strengths under irradiated and unirradiated conditions, it was inferred that creep deformation was dominated by the thermal effect rather than the irradiation at SCWR core condition. The microstructure was examined using transmission electron microscope (TEM) analysis, focusing on void swelling and helium (He) bubble formation. Void formation was observed in the materials irradiated with JOYO at 600degC but not at 700degC. However, its effect on the deformation of components was estimated to be tolerable since their size and density were negligibly small. The manufacturability of the thin-wall, small-diameter tube was confirmed for the potential candidate alloys through the trial tests in the factory where the fuel cladding tube is manufactured. (author)

  7. The effect of carbon content on mechanical properties, failure and corrosion resistance of deposited chromium metal

    Directory of Open Access Journals (Sweden)

    Леонід Кімович Лещинськiй

    2017-06-01

    Full Text Available It has been shown that if choosing a metal composition for surfacing rolls and rollers of continuous casting machines, both the carbon impact on the mechanical and functional properties and the critical values of the chromium concentration, which determine the corrosion resistance of the metal with regard to electrochemical corrosion theory, should be considered as well. The paper studied the effect of chromium and carbon steel the X5-X12 type on the structure, technological strength, mechanical properties, fracturing resistance and corrosion resistance of the weld metal. The composition of chromium tool steels (deposited metal (X5-used for the rolls of hot rolling mills and (X12-used for continuous casting machines rollers correspond to these values. The impact of carbon on the properties of the deposited metal containing chromium was considered by comparing the data for both types of the deposited metal. It was found that for both types of the deposited metal (X5 and X12, the limiting value of the carbon content, providing an optimal combination of strength, ductility, failure resistance is the same. If the carbon content is more than the limiting value – (0,25% the technological strength and failure resistance of the deposited metal significantly reduce. With increasing carbon content from 0,18 to 0,25% the martensite structure has a mixed morphology – lath and plate. The strength and toughness of the deposited metal grow. Of particular interest is simultaneous increase in the specific work of failure resulted from crack inhibition at the boundary with far less solid and more ductile ferrite. As for the 5% chromium metal, the X12 type composition with 0,25% C, is borderline. With a further increase in the carbon content of the metal both ductility and failure resistance sharply decrease and with 0,40% C the growth rate of fatigue crack increases by almost 1,5 times

  8. The effects of MWNT on thermal conductivity and thermal mechanical properties of epoxy

    Science.gov (United States)

    Ismadi, A. I.; Othman, R. N.

    2017-12-01

    Multiwall nanotube (MWNT) was used as filler in various studies to improve thermal conductivity and mechanical properties of epoxy. Present study varied different weight loading (0, 0.1 %, 0.5 %, 1 %, 1.5 %, 3 % and 5 %) of MWNT in order to observe the effects on the epoxy. Nanocomposite was analyzed by dynamic-mechanical thermal analyser (DMTA) and KD2 pro analyzer. DMTA measured storage modulus (E') and glass transition temperature (Tg) of the nanocomposite. Result showed that Tg value of neat epoxy is higher than all MWNT epoxy nanocomposite. Tg values drop from 81.55 °C (neat epoxy) to 65.03 °C (at 0.1 wt%). This may happen due to the agglomeration of MWNT in the epoxy. However, Tg values increases with the increase of MWNT wt%. Tg values increased from 65.03 °C to 78.53 °C at 1 wt%. Increment of storage modulus (E') at 3 °C (glassy region) was observed as the MWNT loading increases. Maximum value of E' during glassy region was observed to be at 5 wt% with (7.26±0.7) E+08 Pa compared to neat epoxy. On the contrary, there is slight increased and slight decreased with E' values at 100 °C (rubbery region) for all nanocomposite. Since epoxy exhibits low thermal conductivity properties, addition of MWNT has enhanced the properties. Optimum value of thermal conductivity was observed at 3 wt%. The values increased up to 9.03 % compared to neat epoxy. As expected, the result showed decrease value in thermal conductivity at 5 wt% as a result of agglomeration of MWNT in the epoxy.

  9. Effect of electronegativity on the mechanical properties of metal hydrides with a fluorite structure

    International Nuclear Information System (INIS)

    Ito, Masato; Setoyama, Daigo; Matsunaga, Junji; Muta, Hiroaki; Kurosaki, Ken; Uno, Masayoshi; Yamanaka, Shinsuke

    2006-01-01

    Bulk titanium, yttrium, and zirconium hydrides, which have the same structure as that of fluorite-type fcc C 1, were produced and their mechanical properties were investigated. With an increase in the hydrogen content, the lattice parameters of titanium and zirconium hydrides increased, whereas those of yttrium hydride decreased. The elastic moduli of titanium and zirconium hydrides decreased by hydrogen addition, whereas those of yttrium hydride increased. There are linear relations between the electronegativities and hydrogen content dependence of the properties. Therefore, the mechanical properties of the metal hydrides are considered to be determined by a common rule based on the electronegativity

  10. Effect of quenching techniques on the mechanical properties of low carbon structural steel

    Directory of Open Access Journals (Sweden)

    K. Miernik

    2010-07-01

    Full Text Available The paper presents the results of the impact of incomplete quenching technique on the mechanical properties of low carbon structural steel.Significant influence of the heating method to the α + γ field was observed on the strength and plasticity after hardening process. The best combination of mechanical properties was obtained for the 3th technique consisting of pre-heating the material to the austenite field, next cooling to the appropriate temperature in the α + γ and hardening from that dual phase region. The high level of toughness with relatively high strength were observed, compared to the properties obtained for the two other ways to quench annealing (incomplete hardening.

  11. The effect of altered lignin composition on mechanical properties of CINNAMYL ALCOHOL DEHYDROGENASE (CAD) deficient poplars.

    Science.gov (United States)

    Özparpucu, Merve; Gierlinger, Notburga; Burgert, Ingo; Van Acker, Rebecca; Vanholme, Ruben; Boerjan, Wout; Pilate, Gilles; Déjardin, Annabelle; Rüggeberg, Markus

    2018-04-01

    CAD-deficient poplars enabled studying the influence of altered lignin composition on mechanical properties. Severe alterations in lignin composition did not influence the mechanical properties. Wood represents a hierarchical fiber-composite material with excellent mechanical properties. Despite its wide use and versatility, its mechanical behavior has not been entirely understood. It has especially been challenging to unravel the mechanical function of the cell wall matrix. Lignin engineering has been a useful tool to increase the knowledge on the mechanical function of lignin as it allows for modifications of lignin content and composition and the subsequent studying of the mechanical properties of these transgenics. Hereby, in most cases, both lignin composition and content are altered and the specific influence of lignin composition has hardly been revealed. Here, we have performed a comprehensive micromechanical, structural, and spectroscopic analysis on xylem strips of transgenic poplar plants, which are downregulated for cinnamyl alcohol dehydrogenase (CAD) by a hairpin-RNA-mediated silencing approach. All parameters were evaluated on the same samples. Raman microscopy revealed that the lignin of the hpCAD poplars was significantly enriched in aldehydes and reduced in the (relative) amount of G-units. FTIR spectra indicated pronounced changes in lignin composition, whereas lignin content was not significantly changed between WT and the hpCAD poplars. Microfibril angles were in the range of 18°-24° and were not significantly different between WT and transgenics. No significant changes were observed in mechanical properties, such as tensile stiffness, ultimate stress, and yield stress. The specific findings on hpCAD poplar allowed studying the specific influence of lignin composition on mechanics. It can be concluded that the changes in lignin composition in hpCAD poplars did not affect the micromechanical tensile properties.

  12. Effects of Sm addition on microstructure and mechanical properties of a Mg-10Y alloy

    Directory of Open Access Journals (Sweden)

    Li Quanan

    2014-01-01

    Full Text Available To further increase the mechanical properties, 0.5wt.% Sm was introduced to a Mg-10Y alloy in this study. The effects of Sm addition on the microstructures and mechanical properties of the Mg-10Y alloy, especially the aged Mg-10Y alloy, were investigated. The microstructure observation and tensile tests were performed by using an optical microscopy, a scanning electron microscopy and a universal material testing machine, respectively. The phase analysis was performed using X-ray diffractometer. The results show that the 0.5wt.% Sm addition can not only promote the formation of fine and dispersed Mg24Y5 phases, but also improve their morphology and distribution; it also increases the thermal stability of Mg24Y5 phases. Sm addition is seen to increase the ultimate tensile strength of Mg-10Y alloy at elevated temperatures (200, 250, 300 and 350 ℃, while decrease the elongation. But the elongation is still up to 7.5% even at 350 ℃. In the range of 250 ℃ to 300℃, the ultimate tensile strength of the alloy reaches its maximum (with a range average of 235 MPa and is not sensitive to the temperature change, which is very useful to the application of heat-resistant magnesium alloys. Even at 350 ℃, the ultimate tensile strength of Mg-10Y-0.5Sm is still up to 155 MPa. Considering both of the ultimate tensile strength and elongation, the maximum application temperature of the Mg-10Y-0.5Sm alloy can be up to 300 ℃. The strengthening mechanisms of Mg-10Y-0.5Sm alloy are mainly attributed to dispersion strengthening of Mg24Y5 phase particles with a certain solubility of Sm and grain refinement strengthening of α-Mg matrix.

  13. Irradiation effects on mechanical properties of fuel element cladding from thermal reactors

    International Nuclear Information System (INIS)

    Chatterjee, S.

    2005-01-01

    During reactor operation, UO 2 expands more than the cladding tube (Zirconium alloys for thermal reactors), is hotter, cracks and swells. The fuel therefore will interact with the cladding, resulting in straining of the later. To minimize the possibility of rupture of the cladding, ideally it should have good ductility as well as high strength. However, the ductility reduces with increase in fuel element burn-up. Increased burn-up also increases swelling of the fuel, leading to increased contact pressure between the fuel and the cladding tube. This would cause strains to be concentrated over localized regions of the cladding. For fuel elements burnup exceeding 40 GWd/T, the contribution of embrittlement due to hydriding, and the increased possibility of embrittlement due to stress corrosion cracking, also need to be considered. In addition to the tensile properties, the other mechanical properties of interest to the performance of cladding tube in an operating fuel element are creep rate and fatigue endurance. Irradiation is reported to have insignificant effect on high cycle endurance limit, and fatigue from fuel element vibration is most unlikely, to be life limiting. Even though creep rates due to irradiation are reported to increase by an order of magnitude, the cladding creep ductility would be so high that creep type failures in fuel element would be most improbable. Thus, the most important limiting aspect of mechanical performance of fuel element cladding has been recognized as the tensile ductility resulting from the stress conditions experienced by the cladding. Some specific fission products of threshold amount (if) deposited on the cladding, and hydride morphology (e.g. hydride lenses). The presentation will brief about irradiation damage in cladding materials and its significance, background of search for better Zirconium alloys as cladding materials, and elaborate on the types of mechanical tests need to be conducted for the evaluation of claddings

  14. The effect of fibre loading and graphene on the mechanical properties of goat hair fibre epoxy composite

    Science.gov (United States)

    Jayaseelan, J.; Vijayakumar, K. R.; Ethiraj, N.; Sivabalan, T.; nallayan, W. Andrew

    2017-12-01

    Composite materials are heterogenous materials containing one or more solid phases. In recent years cost-effective composite making is an ideal task. Hence we have come out with a natural fibre composite, which contains goat hair and epoxy as a binding element, with the combination of Graphene as a main source of enhanced mechanical property. Fabrication of natural composite consists of five layers of goat hair sandwiched in epoxy matrix. These composites made are tested for mechanical properties including Tensile strength, Flexural strength, Inter laminar shear and Impact strength. The mechanical properties of the six composite sets are analyzed and reported.

  15. Mechanical properties and environmental effects of epoxy resins in the neat state and in composites

    International Nuclear Information System (INIS)

    Yang, C.M.P.

    1984-01-01

    The dynamic mechanical properties of graphite fiber reinforced, epoxy matrix composite laminates subjected to loading perpendicular to the plane of lamination and of neat epoxy resin are reported. The centrosymmetric deformation (CSD) test geometry provides an accurate and convenient test mode for the study of the viscoelastic behavior of very stiff graphite-epoxy laminates. It is found that the in-phase and out-of-phase stiffness superpose to form master curves covering a frequency range of 12 decades. By a suitable scaling procedure of the master curves, it is found that the in-phase stiffness has the same shape and the out-of-phase has the same dispersion for all laminates irrespective of the stacking sequence. The dispersion characteristics of in-situ and neat resin epoxy were nearly identical, but with the neat resin having a lower glass-transition temperature. The graphite/epoxy composites and neat resin epoxy have been shown to be sensitive to hygrothermal environment. For postcured specimens the plasticization and inhomogeneous swelling effects due to the moisture absorbed are found to be reversible, in the sense that the initially dry properties of the laminate are recovered after redrying the wet specimen. On the other hand, for as cured specimens, the plasticization and inhomogeneous swelling effects are found to be irreversible under the same hygrothermal environment

  16. Effect of high temperature and type of cooling on some mechanical properties of cement mortar

    Directory of Open Access Journals (Sweden)

    Abdulhussei Faisal

    2018-01-01

    Full Text Available Mortar of cement as construction materials subjected sometimes to high temperature. Some of properties of this mortar being studied after this effect. The effect of high temperature 100, 200, 400 and 700°C (exposed for two hrs. on some mechanical properties (compressive and flexural strength of two groups of cement mortar samples (with and without the addition of crushed bricks and superplasticizer as modifying materials has been studied. Two methods of cooling samples by air and by water for 1/2 hr. was used, then tested after 3, 7 and 28 days. The results showed that the compressive and flexural strength for reference mix exposed to 700°C and water cooling decreased by 65.3 % and 64.7%, respectively, compared with their reference mix tested at 20°C in 28 days. While mixes containing 100% of crushed brick as an additive and air cooling decreases by 12.3% and 9% of their compressive and flexural strength, respectively compared with the mixes tested at 20°C in 28 days. Also showed that the decreases in flexural strength for no sand mixes containing 100% of crushed brick and 4% of superplasticizer exposed to 700°C and then water cooling was 28.2% compared to those for reference mixes tested at 20°C.

  17. Precise Analysis of Microstructural Effects on Mechanical Properties of Cast ADC12 Aluminum Alloy

    Science.gov (United States)

    Okayasu, Mitsuhiro; Takeuchi, Shuhei; Yamamoto, Masaki; Ohfuji, Hiroaki; Ochi, Toshihiro

    2015-04-01

    The effects of microstructural characteristics (secondary dendrite arm spacing, SDAS) and Si- and Fe-based eutectic structures on the mechanical properties and failure behavior of an Al-Si-Cu alloy are investigated. Cast Al alloy samples are produced using a special continuous-casting technique with which it is easy to control both the sizes of microstructures and the direction of crystal orientation. Dendrite cells appear to grow in the casting direction. There are linear correlations between SDAS and tensile properties (ultimate tensile strength σ UTS, 0.2 pct proof strength σ 0.2, and fracture strain ɛ f). These linear correlations, however, break down, especially for σ UTS vs SDAS and ɛ f vs SDAS, as the eutectic structures become more than 3 μm in diameter, when the strength and ductility ( σ UTS and ɛ f) decrease significantly. For eutectic structures larger than 3 μm, failure is dominated by the brittle eutectic phases, for which SDAS is no longer strongly correlated with σ UTS and ɛ f. In contrast, a linear correlation is obtained between σ 0.2 and SDAS, even for eutectic structures larger than 3 μm, and the eutectic structure does not have a strong effect on yield behavior. This is because failure in the eutectic phases occurs just before final fracture. In situ failure observation during tensile testing is performed using microstructural and lattice characteristics. From the experimental results obtained, models of failure during tensile loading are proposed.

  18. EFFECT OF FERTILIZATION ON MECHANICAL PROPERTIES OF THE WOOD OF Eucalyptus grandis

    Directory of Open Access Journals (Sweden)

    Israel Luiz de Lima

    2011-09-01

    Full Text Available The effect of the fertilization in the amount and quality of the produced wood is one of the questions to be considered in the research of the Eucalyptus grandis. The present work aimed to evaluate the fertilization effect in the mechanical properties of Eucalyptus grandis. The population of Eucalyptus grandis was 21 years old and was managed under the system of selective thinning, with application of fertilizers. The factors used in this study were: presence or absence of fertilizers, two positions of log and five radial positions. The influences of the factors and of their combinations were evaluated regarding to compression strength, shear strength, modulus of rupture and modulus of elasticity in static banding. The compressive strength and the modulus of elasticity had been influenced by the factors: fertilizer and radial positions of the log. There was also an increase in the direction of the pith-bark in all studied properties. A good positive relationship was found to exist among the compression strength, the shear, the modulus of rupture and the modulus of elasticity with radial position.

  19. Rare earth effect on microstructure, mechanical and tribological properties of CoCrW coatings

    International Nuclear Information System (INIS)

    Zhang Zhenyu; Lu Xinchun; Han Baolei; Luo Jianbin

    2007-01-01

    Eight different CoCrW coatings doped with rare earth oxide were deposited by supersonic plasma spraying (SPS). Environmental scanning electron microscopy, microhardness tester, X-ray diffractometer, and self-developed tribometer for high temperature were employed to investigate the properties of sprayed coatings. The results show that rare earth can refine the microstructure effectively, and make the element distribution uniform, which leads to the increase of average microhardness and the corresponding decrease of fluctuation range of sectioned surface of SPS coatings. Furthermore, the rare earth can reduce the friction coefficient between the SPS coating and glass during the sliding process at about 973 K largely, and the mechanism of anti-friction is also discussed

  20. Effect of the sterilization process on physical and mechanical properties of the bonacryl bone cement

    International Nuclear Information System (INIS)

    Morejon, L.; Delgado, J.A.; Aguero, L.; Rapado, M.; Ginebra, M.P.; Gil, F.J.; Mendizabal, E.

    2008-01-01

    The use of bone cements of poly(methyl methacrylate) (PMMA) to fix artificial prosthesis to the human body is a habitual method in orthopedic surgery. The hip and the knee joints have a very complex biomechanics and support high loads, for these reasons, acrylic bone cements have to comply with international standards in order to secure the biofuncionality and durability of the implant. In this work we report the effect of sterilization by ethylene oxide or gamma radiation on the BONACRYL Cuban cement. We determined how sterilization methods affect the molecular weight of the polymer as well as its quasi-static mechanical properties. The results demonstrated that the gamma radiation modifies the molecular weight of the PMMA although the compression and bending strength were not affected by the sterilization process applied. (authors)

  1. Effect of austempering temperature and time on mechanical properties of SAE 9260 steel

    Science.gov (United States)

    Dalwatkar, Ranjit; Prabhu, N.; Singh, R. K. P.

    2018-04-01

    This work describes the effect of austempering heat treatment on microstrcuture and mechanical properties of SAE 9260 steel. Steel samples, austenitized at 900 °C for one hour, were isothermally heat treated in the temperature range 300,325 and 350 °C for different times. Microstructural characterization was carried out using optical and scanning electron microscopes. The microstructure of the austempered samples consisted of bainitic ferrite and retained austenite. The volume fraction of retained austenite was determined using X-ray diffraction. Isothermal heat treatment at 350 °C for 20 min, resulted in a retained austenite content of around 38% in the microstructure. Increase in isothermal transformation temperature led to an increase in the fraction of retained austenite. Also, good combination of strength and ductility was obtained in the samples with increased amounts of retained austenite.

  2. Effect of Controlled Rolling and Cooling On Microstructure and Mechanical Properties of 30crmnti Wire Rod

    Science.gov (United States)

    Ruan, Shipeng; Dong, Qing; Zhang, Lei; Wang, Lijun

    2017-09-01

    The effect of controlled rolling and cooling on microstructure and mechanical properties of alloy structure steel 30CrMnTi wire rod with diameter 6.5mm was studied. The results show that the lower finish rolling temperature resulted in a decrease in tensile strength but an increase in elongation and reduction of area. When the finish rolling temperature decreases from 950°C to 850°C, the tensile strength value decreases from 750MPa to 660MPa, and the elongation increases from 21% to 30%, the reduction of area increases from 64% to 71%. The grain size also refines from 20μm to 9.9μm when the finish rolling temperature decreases from 950°C to 850°C. The decrease of tensile strength is due to the change of microstructure which evolved from more bainite to ferrite and pearlite.

  3. Effect of yttrium addition on the microstructure and mechanical properties of ODS RAF steels

    International Nuclear Information System (INIS)

    Auger, M.A.; Castro, V. de; Leguey, T.; Tarcísio-Costa, J.; Monge, M.A.; Muñoz, A.; Pareja, R.

    2014-01-01

    An oxide dispersion strengthened (ODS) alloy with nominal composition Fe–14Cr–2W–0.3Ti–0.24Y (wt.%) was produced by mechanical alloying using elemental powders, and subsequent hot isostatic pressing. The microstructure of the material and characteristics of the oxide particle dispersion were investigated by electron microscopy. The effect of heat treatments on the microhardness and tensile properties at room temperature was also studied. The results show that a fine dispersion of Y–O-rich nanoparticles is achieved, together with larger (Cr, Ti)-rich precipitates. The absence of Ti is apparent in the majority of these nanoparticles, in contrast with reported results for ODS Ti-modified steels processed with Y 2 O 3 addition

  4. Effect of Sphere Properties on Microstructure and Mechanical Performance of Cast Composite Metal Foams

    Directory of Open Access Journals (Sweden)

    Matias Garcia-Avila

    2015-05-01

    Full Text Available Aluminum-steel composite metal foams (Al-S CMF are manufactured using steel hollow spheres, with a variety of sphere carbon content, surface roughness, and wall porosity, embedded in an Aluminum matrix through gravity casting technique. The microstructural and mechanical properties of the material were studied using scanning electron microscopy, energy dispersive spectroscopy, and quasi-static compressive testing. Higher carbon content and surface roughness in the sphere wall were responsible for an increase in formation of intermetallic phases which had a strengthening effect at lower strain levels, increasing the yield strength of the material by a factor of 2, while higher sphere wall porosity resulted in a decrease on the density of the material and improving its cushioning and ductility maintaining its energy absorption capabilities.

  5. Effect of natural fibers on mechanical properties of green cement mortar

    Science.gov (United States)

    AL-Zubaidi, Aseel B.

    2018-05-01

    Natural fibers of banana, reed, palm and coconut were used to reinforce cement composite. Optical microscopy showed that the prepared fibers are different in size and morphology. Nearly equiaxed, ribbon-like and nearly cylindrical morphologies were observed. Each of the utilized natural fibers was incorporated in the cement matrix at 0, 0.25, 0.5, 0.75 and 1.0 wt% and cured for 28 days. The scanning electron micrographs for the 1.0 wt% -reinforced composite showed differences in porosity, grain size and shape. Each of the utilized fibers has different effect on the microstructure of the cement composite that depends on the fiber size and morphology. Water absorption, thermal conductivity, bending strength, hardness and compression strengths were measured for the reinforced cement composite. It is found that the final physical and mechanical properties of the set cement composite depend on the fiber content and fiber type through the differences in their sizes and morphologies.

  6. Effect of large plastic deformation on microstructure and mechanical properties of a TWIP steel

    International Nuclear Information System (INIS)

    Yanushkevich, Z; Belyakov, A; Kaibyshev, R; Molodov, D

    2014-01-01

    The effect of cold rolling on the microstructure evolution and mechanical properties of a cold rolled Fe-0.3C-17Mn-1.5AI TWIP steel was studied. The plate samples were cold rolled with reductions of 20, 40, 60 and 80%. The structural changes were associated with the development of deformation twinning and shear bands. The average spacing between twin boundaries in the transverse section of the rolled plates decreased from ∼190 to 36 nm with an increase in the rolling reduction from 20 to 40%. Upon further rolling to 80% reduction the twin spacing remained at about 30 nm. The cold rolling resulted in significant increase in strength as revealed by tensile tests at an ambient temperature. The offset yield stress approached 1440 MPa, and the ultimate tensile strength increased to 1630 MPa after rolling reduction of 80%. Such significant strengthening was attributed to the development of specific structure consisting of deformation nanotwins with high dislocation density

  7. Effect of yttrium addition on the microstructure and mechanical properties of ODS RAF steels

    Energy Technology Data Exchange (ETDEWEB)

    Auger, M.A., E-mail: maria.auger@materials.ox.ac.uk [Departamento de Física, Universidad Carlos III de Madrid, Av Universidad 30, 28911 Leganés (Spain); Department of Materials, University of Oxford, Parks Road, OX1 3PH Oxford (United Kingdom); Castro, V. de; Leguey, T.; Tarcísio-Costa, J.; Monge, M.A.; Muñoz, A.; Pareja, R. [Departamento de Física, Universidad Carlos III de Madrid, Av Universidad 30, 28911 Leganés (Spain)

    2014-12-15

    An oxide dispersion strengthened (ODS) alloy with nominal composition Fe–14Cr–2W–0.3Ti–0.24Y (wt.%) was produced by mechanical alloying using elemental powders, and subsequent hot isostatic pressing. The microstructure of the material and characteristics of the oxide particle dispersion were investigated by electron microscopy. The effect of heat treatments on the microhardness and tensile properties at room temperature was also studied. The results show that a fine dispersion of Y–O-rich nanoparticles is achieved, together with larger (Cr, Ti)-rich precipitates. The absence of Ti is apparent in the majority of these nanoparticles, in contrast with reported results for ODS Ti-modified steels processed with Y{sub 2}O{sub 3} addition.

  8. EFFECT OF HARDENER ON MECHANICAL PROPERTIES OF CARBON FIBRE REINFORCED PHENOLIC RESIN COMPOSITES

    Directory of Open Access Journals (Sweden)

    S. SULAIMAN

    2008-04-01

    Full Text Available In this paper the effect of hardener on mechanical properties of carbon reinforced phenolic resin composites is investigated. Carbon fibre is one of the most useful reinforcement materials in composites, its major use being the manufacture of components in the aerospace, automotive, and leisure industries. In this study, carbon fibres are hot pressed with phenolic resin with various percentages of carbon fibre and hardener contents that range from 5-15%. Composites with 15% hardener content show an increase in flexural strength, tensile strength and hardness. The ultimate tensile strength (UTS, flexural strength and hardness for 15% hardener are 411.9 MPa, 51.7 MPa and 85.4 HRR respectively.

  9. Effects of cross-section on mechanical properties of Au nanowire

    Energy Technology Data Exchange (ETDEWEB)

    Vazinishayan, Ali; Yang, Shuming, E-mail: shuming.yang@mail.xjtu.edu.cn; Duongthipthewa, Anchalee; Wang, Yiming [State Key Laboratory for manufacturing system engineering, Xi’an Jiaotong University, Xi’an, 710049 (China)

    2016-02-15

    The aim of this paper is study of the effects of multiple cross-section of Au nanowire on mechanical properties. Different cross-section models of Au nanowires including circular, hexagonal, pentagonal and rectangular were simulated by finite element modeling using ABAQUS. In this study, the bending technique was applied so that both ends of the model were clamped with mid-span under loading condition. The cross-sections had the length of 400 nm and the diameter of 40 nm, except the circular cross-section while the rest of the cross-sections had an equivalent diameter. Von Misses stresses distribution were used to define the stress distribution in the cross-section under loading condition, and elastic deformation was analyzed by the beam theory. The results disclosed that the circular and the rectangular models had highest and lowest strengths against plastic deformation, respectively.

  10. Effect of hydrogen on the microstructure, mechanical properties and phase transformations in austenitic steels

    International Nuclear Information System (INIS)

    Li, Y.Y.; Xing, Z.S.

    1989-01-01

    Effect of high-pressure hydrogen charging on the microstructure, mechanical properties and phase transformations in austenitic steels has been investigated and discussed. The results show that the strength and impact toughness of the steels increase slightly and that the ductility decreases after hydrogen charging. The existence of δ-ferrite deteriorates the resistance to hydrogen embrittlement (HE) of the steels. The occurrence of carbide in the steel resulted from aging reduces the ductility of the steel and makes the steel sensitive to HE. The existence of sufficient hydrogen promotes the ε-martensitic transformation and suppresses the α'-martensitic transformation. The permeabilities and diffusivities of hydrogen in the steels have also been determined. (orig.)

  11. Effect of cobalt on microstructural parameters and mechanical properties of Ni-base single crystal superalloys

    International Nuclear Information System (INIS)

    Suzuki, Takanobu; Imai, Hachiro; Yokokawa, Tadaharu; Kobayashi, Toshiharu; Koizumi, Yutaka; Harada, Hiroshi

    2007-01-01

    The alloying effect of Cobalt (Co) to microstructural parameters and mechanical properties, such as partitioning ratios of alloying elements and creep strength, of Re-bearing Ni-base single crystal superalloys have been investigated. The second generation single crystal superalloys, TMS-82+, Ni-7.8Co-4.9Cr-1.9Mo-8.7W-5.3Al-6.0Ta-2.4Re-0.1Hf, in mass% (8Co) was compared to a Co-free (0Co) and 15 mass% Co (15Co) alloy which had the same chemical composition as TMS-82+ except that Co was changed. It was shown that the partitioning ratios of alloying elements trend to k(=X γ /X' γ )=1, as the content of Co was increased. Furthermore, it was found that there was suitable content of Co for the creep strength under various temperature-stress conditions. (author)

  12. EFFECT OF PLASTICIZERS ON MECHANICAL PROPERTIES OF EDIBLE FILM FROM JANENG STARCH – CHITOSAN

    Directory of Open Access Journals (Sweden)

    Narlis Juandi

    2016-10-01

    Full Text Available The interest in the development of edible and biodegradable films has increased because it is every day more evident that non degradable are doing much damage to the environment. In this research, edible films were based on blends of janeng starch in different proportions, added of palm oil or glycerol, which were used as plasticizers. The objective was to study the effect of two different plasticizers, palm oil and glycerol of edible film from janeng starch–chitosan on the mechanical properties and FTIR spectra. Increasing concentration of glycerol as plasticizer resulted tend to increased tensile strength and elongation at break. The tensile strength and elongation at break values for palm oil is higher than glycerol as plasticizer at the same concentration. FTIR spectra show the process of making edible film from janeng starch–chitosan with palm oil or glycerol as plasticizers are physically mixing in the presence of hydrogen interactions between chains.

  13. Effect of Plasticizers on Physicochemical and Mechanical Properties of Chitosan-Gelatin Films

    Science.gov (United States)

    Manshor, N. Mohammed; Rezali, M. I.; Jai, J.; Yahya, A.

    2018-05-01

    Composite chitosan-gelatin films were produced to investigate the effect of plasticizer and composition of chitosan and gelatin on physicochemical and mechanical properties of the films. The films were prepared according to ratio of chitosan: gelatin of 1:1, 1:2 and 2:1. For each film, glycerol, sorbitol and sucrose were added as plasticizer. The film forming solution was poured on a glass plate and dried for 12 hours in an oven at 60°C. The highest tensile strength was 4.04 MPa for films of ratio 2:1 plasticized with glycerol compared to sorbitol and sucrose which were 3.94 MPa and 3.84 MPa, respectively. However, films plasticized with sorbitol at ratio of 1:2 had the highest percent elongation which was 68.20%, followed by glycerol and sucrose which were 26.51% and 24.08%, respectively.

  14. Effect of boron and phosphate compounds on physical, mechanical, and fire properties of wood-polypropylene composites

    Science.gov (United States)

    Nadir Ayrilmis; Turgay Akbulut; Turker Dundar; Robert H. White; Fatih Mengeloglu; Umit Buyuksari; Zeki Candan; Erkan Avci

    2012-01-01

    Physical, mechanical, and fire properties of the injection-molded wood flour/polypropylene composites incorporated with different contents of boron compounds; borax/boric acid and zinc borate, and phosphate compounds; mono and diammonium phosphates were investigated. The effect of the coupling agent content, maleic anhydride-grafted polypropylene, on the properties of...

  15. Effect of weld spacing on microstructure and mechanical properties of CLAM electron beam welding joints

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Yutao; Huang, Bo, E-mail: aufa0007@163.com; Zhang, Junyu; Zhang, Baoren; Liu, Shaojun; Huang, Qunying

    2016-11-15

    Highlights: • The welded joints of CLAM steel with different weld spacings have been fabricated with electron beam welding, and a simplified model of CLAM sheet was proposed. • The microstructure and mechanical properties such as microhardness, impact and tensile were investigated at different welding spacing for both conditions of as-welded and post weld heat treatment (PWHT). • The effect of the welding thermal cycle was significantly when the weld spacings were smaller than 4 mm. • When the weld spacing was small enough, the original microstructures would be fragmented with the high heat input. - Abstract: China low activation martensitic (CLAM) steel has been chosen as the primary structural material in the designs of dual function lithium-lead (DFLL) blanket for fusion reactors, China helium cooled ceramic breeder (HCCB) test blanket module (TBM) for ITER and China fusion engineering test reactor (CFETR) blanket. The cooling components of the blankets are designed with high density cooling channels (HDCCs) to remove the high nuclear thermal effectively. Hence, the welding spacing among the channels are small. In this paper, the welded joints of CLAM steel with different weld spacings have been fabricated with electron beam welding (EBW). The weld spacing was designed to be 2 mm, 3 mm, 4 mm, 6 mm and 8 mm. The microstructure and mechanical properties such as microhardness, impact and tensile were investigated at different welding spacing for both conditions of as-welded and post weld heat treatment (PWHT). The PWHT is tempering at 740 °C for 120 min. The results showed that the grain size in the heat affected zone (HAZ) increased with the increasing weld spacing, and the joint with small weld spacing had a better performance after PWHT. This work would give useful guidance to improve the preparation of the cooling components of blanket.

  16. Effects of plantain and corn starches on the mechanical and disintegration properties of paracetamol tablets.

    Science.gov (United States)

    Akin-Ajani, Olufunke D; Itiola, Oludele A; Odeku, Oluwatoyin A

    2005-10-22

    The effects of plantain starch obtained from the unripe fruit of the plant Musa paradisiaca L. (Musaceae) on the mechanical and disintegration properties of paracetamol tablets have been investigated in comparison with the effects of corn starch BP using a 2(3) factorial experimental design. The individual and combined effects of nature of starch binder (N), concentration of starch binder (C), and the relative density of tablet (RD) on the tensile strength (TS), brittle fracture index (BFI), and disintegration time (DT) of the tablets were investigated. The ranking of the individual effects on TS was RD > C > N, on BFI was C > RD > N and on DT was N > C > RD. The ranking for the interaction effects on TS and DT was N-C > N-RD > C-RD, while that on BFI was N-C > C-RD > N-RD. Changing nature of starch from a "low" (plantain starch) to a "high" (corn starch) level, increasing the concentration of starch binding agent from 2.5% to 10.0% wt/wt, and increasing relative density of the tablet from 0.80 to 0.90, led to increase in the values of TS and DT, but a decrease in BFI. Thus, tablets containing plantain starch had lower tensile strength and disintegration time values than those containing corn starch, but showed better ability to reduce the lamination and capping tendency in paracetamol tablet formulation. The interaction between N and C was significantly (P < .001) higher than those between N and RD and between C and RD. There is therefore the need to carefully choose the nature (N) and concentration (C) of starch used as binding agent in tablet formulations to obtain tablets of desired bond strength and disintegration properties. Furthermore, plantain starch could be useful as an alternative binding agent to cornstarch, especially where faster disintegration is required and the problems of lamination and capping are of particular concern.

  17. Heat treatment effect on the texture and mechanical properties of the VT14 alloy cylinders

    International Nuclear Information System (INIS)

    Betsofen, S.Ya.; Khorev, A.I.; Babarehko, A.A.; Krasnozhon, A.I.; Kadobnova, N.V.

    1978-01-01

    The mechanical properties and the texture of cylinders made of VT14 alloy in the conditions after quenching from the temperature of 880 deg C, followed by ageing for 16 hours at the temperature of about 480 deg C, or after 20 minutes annealing at the temperature of 750 deg C, were stu--died, while taking into account the influence of intermediate preheats up to 800-1000 deg C prior to carrying into effect those kinds of heat treatment. It is shown that the texture of cylinders after heat treatment without the intermediate preheats prior to quenching is characterized by an increased density of poles in the axial and tangential directions. It is the preheating up to 1000 deg C prior to quenching that shifts the texture maxima in the axial direction and causes the appearance of component (0001). Under the effect of the intermediate preheating up to 1000 deg C, the biaxial and monoaxial strength of the cylinders decreases, whereas their tendency to brittle failure increases. The mechanical strength of all the thermally hardened cylinders, independently of the intermediate treatment, is in the tangential direction higher than in the axial direction. The proportions of the structure and texture factors have been assessed in the variation of the structural strength of the cylinders during the course of their heat treatment

  18. Effect of the leaching of calcium hydroxide from cement paste on mechanical and physical properties

    International Nuclear Information System (INIS)

    Carde, C.; Francois, R.

    1997-01-01

    This paper deals with the effect of the leaching process of cement based materials on their mechanical and physical properties. In order to characterize this effect, the authors have performed experiments on cement paste samples. The leaching process was achieved by the use of a 50% concentrate solution of ammonium nitrate. Both compression tests and water porosity tests were conducted on micro-cylinder samples (10, 12, 14 and 20 mm of diameter) because of the slow kinetics of degradation due to the leaching. The deterioration of the cement paste and the mortar exposed to the action of the ammonium nitrate was manifested by a peripheral zone of less resistance. This process induces mainly a total leaching of Ca(OH) 2 and a progressive decalcification of C-S-H which leads to a gradient of C/S ratio in the leaching zone. Both mechanical tests and water porosity tests show that there is a linear variation of the loss of strength and the increase in porosity in relation to the ratio of degraded area over total area of the sample A d /A t . It means that both compressive resistance and water porosity of the leaching zone are constant whatever the size of the degraded zone and then whatever the time of exposure to the chemical attack. So the authors could venture the hypothesis that the dissolution of calcium hydroxide is the essential parameter governing both decrease in strength and increase in porosity

  19. Effects of tensile test parameters on the mechanical properties of a bimodal Al–Mg alloy

    International Nuclear Information System (INIS)

    Magee, Andrew; Ladani, Leila; Topping, Troy D.; Lavernia, Enrique J.

    2012-01-01

    The properties of aluminum alloy (AA) 5083 are shown to be significantly improved by grain size reduction through cryomilling and the incorporation of unmilled Al particles into the material, creating a bimodal grain size distribution consisting of coarse grains in a nanocrystalline matrix. To provide insight into the mechanical behavior and ultimately facilitate engineering applications, the present study reports on the effects of coarse grain ratio, anisotropy, strain rate and specimen size on the elastic–plastic behavior of bimodal AA 5083 evaluated in uniaxial tension tests using a full-factorial experiment design. To determine the governing failure mechanisms under different testing conditions, the specimens’ failure surfaces were analyzed using optical and electron microscopy. The results of the tests were found to conform to Joshi’s plasticity model. Significant anisotropy effects were observed, in a drastic reduction in strength and ductility, when tension was applied perpendicular (transverse) to the direction of extrusion. These specimens also exhibited a smooth, flat fracture surface morphology with a significantly different surface texture than specimens tested in the axial direction. It was found that decreasing specimen thickness and strain rate served to increase both the strength and ductility of the material. The failure surface morphology was found to differ between specimens of different thicknesses.

  20. Effect of gamma radiation and endodontic treatment on mechanical properties of human and bovine root dentin

    International Nuclear Information System (INIS)

    Novais, Veridiana Resende; Soares, Priscilla Barbosa Ferreira; Guimaraes, Carlla Martins; Schliebe, Lais Rani Sales Oliveira; Braga, Stella Sueli Lourenco; Soares, Carlos Jose

    2016-01-01

    This study evaluated the effect of gamma radiation and endodontic treatment on the microhardness and flexural strength of human and bovine root dentin. Forty single rooted human teeth and forty bovine incisor teeth were collected, cleaned and stored in distilled water at 4 °C. The human and bovine teeth were divided into 4 groups (n=10) resulting from the combination of two study factors: first, regarding the endodontic treatment in 2 levels: with or without endodontic treatment; and second, radiotherapy in two levels: with or without radiotherapy by 60 Gy of Co-60 gamma radiation fractioned into 2 Gy daily doses five days per week. Each tooth was longitudinally sectioned in two parts; one-half was used for the three-point bending test and the other for the Knoop hardness test (KHN). Data were analyzed by 3-way ANOVA and Tukey HSD test (α=0.05). No significant difference was found for flexural strength values. The human dentin had significantly higher KHN than the bovine. The endodontic treatment and radiotherapy resulted in significantly lower KHN irrespective of tooth origin. The results indicated that the radiotherapy had deleterious effects on the microhardness of human and bovine dentin and this effect is increased by the interaction with endodontic therapy. The endodontic treatment adds additional negative effect on the mechanical properties of radiated tooth dentin; the restorative protocols should be designed taking into account this effect. (author)

  1. Effect of gamma radiation and endodontic treatment on mechanical properties of human and bovine root dentin

    Energy Technology Data Exchange (ETDEWEB)

    Novais, Veridiana Resende; Soares, Priscilla Barbosa Ferreira; Guimaraes, Carlla Martins; Schliebe, Lais Rani Sales Oliveira; Braga, Stella Sueli Lourenco; Soares, Carlos Jose, E-mail: carlosjsoares@ufu.br [Universidade Federal de Uberlandia (UFU), MG (Brazil)

    2016-11-15

    This study evaluated the effect of gamma radiation and endodontic treatment on the microhardness and flexural strength of human and bovine root dentin. Forty single rooted human teeth and forty bovine incisor teeth were collected, cleaned and stored in distilled water at 4 °C. The human and bovine teeth were divided into 4 groups (n=10) resulting from the combination of two study factors: first, regarding the endodontic treatment in 2 levels: with or without endodontic treatment; and second, radiotherapy in two levels: with or without radiotherapy by 60 Gy of Co-60 gamma radiation fractioned into 2 Gy daily doses five days per week. Each tooth was longitudinally sectioned in two parts; one-half was used for the three-point bending test and the other for the Knoop hardness test (KHN). Data were analyzed by 3-way ANOVA and Tukey HSD test (α=0.05). No significant difference was found for flexural strength values. The human dentin had significantly higher KHN than the bovine. The endodontic treatment and radiotherapy resulted in significantly lower KHN irrespective of tooth origin. The results indicated that the radiotherapy had deleterious effects on the microhardness of human and bovine dentin and this effect is increased by the interaction with endodontic therapy. The endodontic treatment adds additional negative effect on the mechanical properties of radiated tooth dentin; the restorative protocols should be designed taking into account this effect. (author)

  2. Effect of three filler types on mechanical properties of dental composite

    Directory of Open Access Journals (Sweden)

    Pahlavan A.

    2005-06-01

    Full Text Available Statement of Problem: Despite the improvements achieved in the field of dental composites, their strength, longevity, and service life specially in high stress areas is not confirmed. Finding better fillers can be a promising step in this task. Purpose: The purpose of this study was to investigate the effect of the filler type on the mechanical properties of a new experimental dental composite and compare these with the properties of composite containing conventional glass filler. Materials and Methods: Experimental composites were prepared by mixing silane-treated fillers with monomers, composed of 70% Bis-GMA and 30% TEGDMA by weight. Fillers were different among the groups. Glass, leucite ceramic and lithium disilicate were prepared as different filler types. All three groups contained 73% wt filler. Comphorquinone and amines were chosen as photo initiator system. Post curing was done for all groups. Diametral tensile strength (DTS, flexural strength and flexural modulus were measured and compared among groups. Data were analyzed with SPSS package using one-way ANOVA test with P<0.05 as the limit of significance. Results: The results showed that the stronger ceramic fillers have positive effect on the flexural strength. Ceramic fillers increased the flexural strength significantly. No significant differences could be determined in DTS among the groups. Flexural modulus can be affected and increased by using ceramic fillers. Conclusion: Flexural strength is one of the most significant properties of restorative dental materials. The higher flexural strength and flexural modulus can be achieved by stronger ceramic fillers. Any further investigation in this field would be beneficial in the development of restorative dental materials.

  3. Effects of local mechanical and fracture properties on LBB behavior of a dissimilar metal welded joint in nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Du, L.Y.; Wang, G.Z., E-mail: gzwang@ecust.edu.cn; Xuan, F.Z.; Tu, S.T.

    2013-12-15

    Highlights: • Effect of local mechanical and fracture properties on LBB behavior were investigated. • Considering local mechanical properties leads to slightly high LBB curve. • Use of fracture resistance of base or weld will produce non-conservative LBB result. • Local fracture properties of interface region cannot be ignored in LBB analysis. - Abstract: In this paper, three-dimensional finite element models with and without considering local mechanical properties were built for a dissimilar metal welded joint (DMWJ) connected the safe end to pipe-nozzle of a reactor pressure vessel. The inner circumferential surface cracks were postulated at the interface of A508 steel and buttering Alloy52Mb. Based on the elastic–plastic fracture mechanics theory of J-integral, the crack growth stability was analyzed. The effects of the local mechanical and fracture resistance properties on LBB behavior were investigated. The results show that considering local mechanical properties leads to slightly high LBB curve. For the A508/Alloy52Mb interface region cracks in the DMWJ, if the fracture resistance curve of base metal A508 or the buttering Alloy52Mb is used, the non-conservative (unsafe) LBB assessment result will be produced. With increasing the applied bending moment, the degree of un-conservatism in LBB behavior becomes large. Therefore, to obtain accurate LBB assessment results, the local fracture resistance properties of the interface region should be used.

  4. Effect of tool shape and welding parameters on mechanical properties and microstructure of dissimilar friction stir welded aluminium alloys

    OpenAIRE

    Chetan Aneja; Amit Handa

    2016-01-01

    In the present experimental study, dissimilar aluminum alloy AA5083 and AA6082 were friction stir welded by varying tool shape, welding speed and rotary speed of the tool in order to investigate the effect of varying tool shape and welding parameters on the mechanical properties as well as microstructure. The friction stir welding (FSW) process parameters have great influence on heat input per unit length of weld. The outcomes of experimental study prove that mechanical properties increases w...

  5. Effect of thermo-mechanical treatments on the microstructure and mechanical properties of an ODS ferritic steel

    International Nuclear Information System (INIS)

    Oksiuta, Z.; Mueller, P.; Spaetig, P.; Baluc, N.

    2011-01-01

    The Fe-14Cr-2W-0.3Ti-0.3Y 2 O 3 oxide dispersion strengthened (ODS) reduced activation ferritic (RAF) steel was fabricated by mechanical alloying of a pre-alloyed, gas atomised powder with yttria nano-particles, followed by hot isostatic pressing and thermo-mechanical treatments (TMTs). Two kinds of TMT were applied: (i) hot pressing, or (ii) hot rolling, both followed by annealing in vacuum at 850 deg. C. The use of a thermo-mechanical treatment was found to yield strong improvement in the microstructure and mechanical properties of the ODS RAF steel. In particular, hot pressing leads to microstructure refinement, equiaxed grains without texture, and an improvement in Charpy impact properties, especially in terms of the upper shelf energy (about 4.5 J). Hot rolling leads to elongated grains in the rolling direction, with a grain size ratio of 6:1, higher tensile strength and reasonable ductility up to 750 deg. C, and better Charpy impact properties, especially in terms of the ductile-to-brittle transition temperature (about 55 deg. C).

  6. Effect of thermo-mechanical treatments on the microstructure and mechanical properties of an ODS ferritic steel

    Energy Technology Data Exchange (ETDEWEB)

    Oksiuta, Z., E-mail: oksiuta@pb.edu.pl [Bialystok Technical University, Mechanical Department, Wiejska 45c, 15-351 Bialystok (Poland); Mueller, P.; Spaetig, P.; Baluc, N. [Ecole Polytechnique Federale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas, Association Euratom-Confederation Suisse, 5232 Villigen PSI (Switzerland)

    2011-05-15

    The Fe-14Cr-2W-0.3Ti-0.3Y{sub 2}O{sub 3} oxide dispersion strengthened (ODS) reduced activation ferritic (RAF) steel was fabricated by mechanical alloying of a pre-alloyed, gas atomised powder with yttria nano-particles, followed by hot isostatic pressing and thermo-mechanical treatments (TMTs). Two kinds of TMT were applied: (i) hot pressing, or (ii) hot rolling, both followed by annealing in vacuum at 850 deg. C. The use of a thermo-mechanical treatment was found to yield strong improvement in the microstructure and mechanical properties of the ODS RAF steel. In particular, hot pressing leads to microstructure refinement, equiaxed grains without texture, and an improvement in Charpy impact properties, especially in terms of the upper shelf energy (about 4.5 J). Hot rolling leads to elongated grains in the rolling direction, with a grain size ratio of 6:1, higher tensile strength and reasonable ductility up to 750 deg. C, and better Charpy impact properties, especially in terms of the ductile-to-brittle transition temperature (about 55 deg. C).

  7. Effects of electron irradiation in space environment on thermal and mechanical properties of carbon fiber/bismaleimide composite

    International Nuclear Information System (INIS)

    Yu, Qi; Chen, Ping; Gao, Yu; Ma, Keming; Lu, Chun; Xiong, Xuhai

    2014-01-01

    Highlights: •Electron irradiation decreased the storage modulus finally. •T g decreased first and then increased and finally decreased. •The thermal stability was reduced and then improved and finally decreased. •The changing trend of flexural strength and ILSS are consistent. -- Abstract: The effects of electron irradiation in simulated space environment on thermal and mechanical properties of high performance carbon fiber/bismaleimide composites were investigated. The dynamic mechanical properties of the composites exposed to different fluences of electron irradiation were evaluated by Dynamic mechanical analysis (DMA). Thermogravimetric analysis was applied to investigate the changes in thermal stability of the resin matrix after exposure to electron irradiation. The changes in mechanical properties of the composites were evaluated by flexural strength and interlaminar shear strength (ILSS). The results indicated that electron irradiation in high vacuum had an impact on thermal and mechanical properties of CF/BMI composites, which depends on irradiation fluence. At lower irradiation fluences less than 5 × 10 15 cm −2 , the dynamic storage modulus, cross-linking degree, thermal stability and mechanical properties that were determined by a competing effect between chain scission and cross-linking process, decreased firstly and then increased. While at higher fluences beyond 5 × 10 15 cm −2 , the chain scission process was dominant and thus led to the degradation in thermal and mechanical properties of the composites

  8. SOLUTION TREATMENT EFFECT ON MICROSTRUCTURE AND MECHANICAL PROPERTIES OF AUTOMOTIVE CAST ALLOY

    Directory of Open Access Journals (Sweden)

    Eva Tillová

    2012-02-01

    Full Text Available The contribution describes influence of the heat treatment (solution treatment at temperature 545°C and 565°C with different holding time 2, 4, 8, 16 and 32 hours; than water quenching at 40°C and natural aging at room temperature during 24 hours on mechanical properties (tensile strength and Brinell hardness and microstructure of the secondary AlSi12Cu1Fe automotive cast alloy. Mechanical properties were measured in line with EN ISO. A combination of different analytical techniques (light microscopy, scanning electron microscopy (SEM were therefore been used for study of microstructure. Solution treatment led to changes in microstructure includes the spheroidization and coarsening of eutectic silicon. The dissolution of precipitates and the precipitation of finer hardening phase further increase the hardness and tensile strength of the alloy. Optimal solution treatment (545°C/4 hours most improves mechanical properties and there mechanical properties are comparable with mechanical properties of primary AlSi12Cu1Fe alloy. Solution treatment at 565 °C caused testing samples distortion, local melting process and is not applicable for this secondary alloy with 12.5 % Si.

  9. Grain size effect on the mechanical properties of neutron irradiated niobium

    International Nuclear Information System (INIS)

    Gusev, M. N.; Maksimkin, O.P.

    2000-01-01

    Samples for mechanical tests were prepared from niobium of technical purity and have form of plates (10·3.5 ·0.3mm) with grain size from 2 to 100 mcm. Neutron irradiation was carried out at the reactor WWR-K to the fluence of 2·10 22 n/m 2 ( Angstroem >0.1 MeV). Tests on uniaxial tension at 293K were performed at the facility, evolving Calvet's microcalorimeter and miniature rapture machine. The developed technique enabled to record heat effects just during the deformation process. As experimental results the characteristics of strength and ductility were defined, as well as values of the latent energy E s , accumulated in material in the process of its deformation up to the moment of destruction. It was found that irradiation of niobium with large-grain structure by neutrons leads to increasing of strength characteristics (yield strength σ 0 .2 changes from 130 to 210 MPa, time-resistance σ b from 200 to 230 MPa) and decreasing of ductility from 36 to 28%. As this takes place the capability of the material to accumulate and dissipate energy of plastic deformation suffers substantial change. There were revealed some additional effects, for instance, the radiation annealing hardening (RAH) (i.e. additional change of properties of irradiated material at annealing), whose maximum takes place at 473K. Its temperature and kinetic parameters were determined in this work. Decreasing of grain size usually leads to decreasing of strengthening under irradiation and to decreasing of RAH effect intensity at subsequent annealing. At the same time decreasing of radiation embrittlement is observed. Consequently, creation of fine-grain structure for some cases can favored the stability of material's properties under irradiation. The obtained results are discussed in context of views on grain boundaries as a defect sink. The relation 'grain boundary volume - grain matrix volume', its influence on RAH-effect and value of latent energy are considered

  10. Effects of chemical contamination on HDPE - thermo-mechanical and characterisation properties

    International Nuclear Information System (INIS)

    Ashraf, G.

    2002-01-01

    Studying the effects of chemical contamination on HDPE is an important precursor in recycling of plastic packaging and polymer reprocessing. This research involves and discusses the results of an in-depth investigation into the effects of chemically contaminating, using various acids, commercial grade high density polyethylene (HDPE) used commonly in packaging applications. An extensive formulation study was conducted and it became obvious that in some cases degradation had occurred to HDPE when chemically contaminated with particular functional group types. The functional groups in contaminated HDPE were successfully identified. A variety of analytical techniques such as Fourier transform Infra-red spectroscopy, X-ray Florescence, x-ray photo electron spectroscopy could identify compounds such as HCl acid, HNO/sub 3/ acid and other related contaminants. Some chemical additives had effects on the mechanical and thermal properties when added in the most appropriate concentration. The results have shown lower tensile modulus and strength tensile elongation, lower modular weight, melt flow index and crystallinity. The amount of contaminant concentration, the type of chemical functional groups used and the type of test selected to affect degradation are important factors in proving the effects of chemical contamination on HDPE in the melt state. (author)

  11. Effects of thickness and surface roughness on mechanical properties of aluminum sheets

    International Nuclear Information System (INIS)

    Suh, Chang Hee; Jung, Yun Chul; Kim, Young Suk

    2010-01-01

    The effect of thickness on the mechanical properties of Al 6K21-T4 sheet specimens under uniaxial tension was investigated. In order to reduce the thickness of the specimens without changing the microstructure and grain size, chemical etching was carried out, resulting in Al sheets ranging from 0.40 mm to 1.58 mm in thickness. Additionally, the effect of surface roughness was determined by finite element (FE) calculations performed using FE code MARC 2007. Tensile specimens of varying surface roughness were modeled and simulated. An analysis of the combined effects of the thickness and surface roughness revealed that the yield and tensile strengths decreased when the number of grains over the thickness was decreased. The ductility also decreased when reducing the thickness. An FE simulation showed that both the surface roughness and thickness affected the flow-curve shape. Moreover, the effect of the surface roughness tended to increase when decreasing the sheet thickness of specimens having the same roughness

  12. Effect of nanoclay particles on some physical and mechanical properties of soils

    Directory of Open Access Journals (Sweden)

    H Sharifnasab

    2016-04-01

    Full Text Available Introduction: As a mechanical tillage practices on soil preparation improve soil structure, increase in porosity, better distribution of soil aggregates and eventually modify the physical properties of soil. The use of nano-technology in agricultural science and its application in tillage for improving the physical properties and mechanical issues has grown substantially. Nanotechnology is an appropriate way to reduce soil limitations. However the nanoparticles are very small amounts in soil, due to features such as high surface area, surface charge (appearance and sometimes porous nano-engineering of physical-chemical properties of soil are affected significantly (Mohammadi & Niazian, 2013. To use of nanomaterials in the territory of a new issue (Taipodia et al., 2011. Small developments on the use of nanoparticles to improve soil quality and land reform have been taken (Theron et al., 2008. Clay soil was used to enhance the compressive strength (Yonekura & Miwa, 1993. Nanosilica particle effects were examined for increasing resistance against penetration and consolidation (Noll et al., 1992. In 2005, these particles were used to increase adhesion and reduce viscosity. It seemed that the adhesion of the particles was depended on Nanosilica (Mohammadi & Niazian, 2013. The use of nanomaterials showed that the increased pH and soil fertility, improved soil physical structure, and reduced mobility, availability and toxicity of heavy metals and other environmental factors and those that will stabilize the soil components and subsides the erosion in the mining pick, (Lal, 2008. In agriculture, the soil conditioner studies have shown that nanoparticles can mine the soil quality by increasing water-holding capacity, increasing silt and clay and improve levels of nutrients, and eliminate toxins, (Liu and Lal, 2012.In this study, the effect on some physical and mechanical properties of soil contain clay gradation, Atterberg limits, specifications

  13. Effect of sintering on structure and mechanical properties of alumina-15 vol% zirconia nanocomposite compacts

    International Nuclear Information System (INIS)

    Maneshian, Mohammad H.; Banerjee, Malay K.

    2010-01-01

    The sintering and densification behavior of high energy ball milled (HEBM-ed) alumina-15 vol% zirconia nanocomposite were carried out and the probable tetragonal to monoclinic phase transformation of ZrO 2 during sintering was investigated. Evolution of microstructure resulting from sintering was followed up by means of scanning electron microscopy (SEM) on polished samples, and the degree of phase transformation was determined by quantitative X-ray analysis (XRD). Moreover, synergetic effect of milling time and dopant composition on properties such as relative density, hardness, and fracture toughness was studied. The results have shown that mechanical properties of the composites were strongly dependent on the dopant content, structure and the fraction of tetragonal to monoclinic induced by HEBM and subsequent sintering. The extent of retention of t-ZrO 2 depends on the balance of magnitude of the strain energy arising from HEBM and releasing from sintering. In fact, compacts with aggressive HEBM history showed improved fracture toughness. Also it is shown the homogeneous microstructure obtained by HEBM and subsequent sintering promotes better densification.

  14. Effect of incorporation of zinc oxide nanoparticles on mechanical properties of conventional glass ionomer cements.

    Science.gov (United States)

    Panahandeh, Narges; Torabzadeh, Hassan; Aghaee, Mohammadamin; Hasani, Elham; Safa, Saeed

    2018-01-01

    The aim of this study is to investigate the physical properties of conventional and resin-modified glass ionomer cements (GICs) compared to GICs supplemented with zinc oxide (ZnO) nanofiller particles at 5% (w/w). In this in vitro study, ZnO nanoparticles of different morphologies (nanospherical, nanorod, and nanoflower) were incorporated to glass ionomer powder. The samples were subjected to the flexural strength ( n = 20) and surface hardness test ( n = 12) using a universal testing machine and a Vickers hardness machine, respectively. Surface analysis and crystal structure of samples were performed with scanning electron microscope and X-radiation diffraction, respectively. The data were analyzed using one-way ANOVA, Shapiro-Wilk, and Tukey's tests ( P glass ionomer containing nanoparticles was not significantly different from the control group ( P > 0.05). The surface hardness of the glass ionomer containing nanospherical or nanoflower ZnO was significantly lower than the control group ( P glass ionomer containing nanorod ZnO was not significantly different from the control group ( P = 0.868). Incorporation of nanospherical and nanoflower ZnO to glass ionomer decreased their surface hardness, without any changes on their flexural strength. Incorporation of nanorod ZnO particles caused no effect on the mechanical properties.

  15. Effect of Hygrothermal Aging on the Mechanical Properties of Fluorinated and Nonfluorinated Clay-Epoxy Nanocomposites.

    Science.gov (United States)

    Hamim, Salah U; Singh, Raman P

    2014-01-01

    Hydrophilic nature of epoxy polymers can lead to both reversible and irreversible/permanent changes in epoxy upon moisture absorption. The permanent changes leading to the degradation of mechanical properties due to combined effect of moisture and elevated temperature on EPON 862, Nanomer I.28E, and Somasif MAE clay-epoxy nanocomposites are investigated in this study. The extent of permanent degradation on fracture and flexural properties due to the hygrothermal aging is determined by drying the epoxy and their clay-epoxy nanocomposites after moisture absorption. Significant permanent damage is observed for fracture toughness and flexural modulus, while the extent of permanent damage is less significant for flexural strength. It is also observed that permanent degradation in Somasif MAE clay-epoxy nanocomposites is higher compared to Nanomer I.28E clay-epoxy nanocomposites. Fourier transform infrared (FTIR) spectroscopy revealed that both clays retained their original chemical structure after the absorption-desorption cycle without undergoing significant changes. Scanning electron microscopy (SEM) images of the fracture surfaces provide evidence that Somasif MAE clay particles offered very little resistance to crack propagation in case of redried specimens when compared to Nanomer I.28E counterpart. The reason for the observed higher extent of permanent degradation in Somasif MAE clay-epoxy system has been attributed to the weakening of the filler-matrix interface.

  16. Mechanical properties of papercrete

    Directory of Open Access Journals (Sweden)

    Zaki Harith

    2018-01-01

    Full Text Available This paper studies the uses, of waste paper as an additional material in concrete mixes. Papercrete is a term as the name seems, to imply a mixture of paper and concrete. It is a new, composite material using waste paper, as a partial addition of Portland cement, and is a sustainable, building material due to, reduced amount of waste paper being put to use. It gains, latent strength due to presence of hydrogen bonds in microstructure of paper. Papercrete has been, reported to be a low cost alternative, building construction, material and has, good sound absorption, and thermal insulation; to be a lightweight and fire-resistant material. The percent of waste paper used (after treating namely (5%, 10%, 15% and 20% by weight of cement to explore the mechanical properties of the mixes (compressive strength, splitting tensile strength, flexural strength, density, as compared with references mixes, it was found that fresh properties affected significantly by increasing the waste paper content. The compressive strength, splitting tensile strength, flexural strength and density got decreased with increase in the percentage of paper.

  17. Effect of intercritical heat treatment on mechanical properties of reinforcing steel bars

    International Nuclear Information System (INIS)

    Abro, M.I.; Memon, R.A.; Soomro, I.A.; Aftab, U.

    2017-01-01

    Intercritical heat treatments attempts were made to enhance the mechanical properties of reinforcing steel bars milled from scrap metal. For this, two grades of steel bars were obtained from different steel mills and their mechanical properties that include hardness, ultimate tensile strength, and percent elongation before and after intercritical heat treatment were determined. Results indicated that 25.5 and 17.6%, improvements in UTS (Ultimate Tensile Strength) and 18.8 and 14.3% improvement in percent elongation in two grades of reinforcing steel samples containing 0.17 and 0.24% carbon respectively was achieved while heating at 750 degree C for 2h. Appreciable improvement in the mechanical properties was noted due to birth of sufficient quantity of martensite along with ferrite. (author)

  18. Effect of the Addition of Carbon Nanomaterials on Electrical and Mechanical Properties of Wood Plastic Composites

    Directory of Open Access Journals (Sweden)

    Xingli Zhang

    2017-11-01

    Full Text Available Wood Plastic Composites (WPCs are a new generation of green composites that could optimize the use of harvested trees and increase the entire value chain. In this study, the electrical and mechanical properties of WPCs containing carbon blacks (CB, flake graphite (FG and carbon nanotubes (CNTs have been investigated. The electrical property of WPCs is improved significantly owing to the introduction of these carbon nanomaterial fillers. The volume and surface resistivity values of the investigated composites all obviously decreased with the increase in filler content, especially CNTs, which displayed the most satisfactory results. Based on a series of laboratory experiments carried out to investigate the mechanical performance, it can be concluded that the addition of the carbon nanomaterial fillers decreases the mechanical properties of WPCs slightly with the increase in filler content because of the weak interfacial interactions between the fillers and polymer matrix.

  19. Effect of natural fibres on the mechanical properties of thermoplastic starch

    Science.gov (United States)

    Oniszczuk, Tomasz; Wójtowicz, Agnieszka; Moácicki, Leszek; Mitrus, Marcin; Kupryaniuk, Karol; Kusz, Andrzej; Bartnik, Grzegorz

    2016-04-01

    This paper presents the results covering the mechanical properties of thermoplastic potato starch granules with flax, cellulose fibre, and pine bark addition. A modified single screw extrusion-cooker TS-45 with L/D = 18 and an additional cooling section of the barrel was used as the processing unit. The establishment influence of the fibre addition, as well as the extrusion-cooker screw speed, on the mechanical properties of the thermoplastic starch granules was the main objective of the investigation. The maximum force during compression to 50% of the sample diameter, elastic modulus, and compression strength were evaluated. Significant differences were noted depending on the amount of fibre used, while only an insignificant influence of screw speed on the mechanical properties of the granulate was reported. An increased amount of fibres lowered the maximum force as well as the elastic modulus and compression strength of the thermoplastic starch granulates.

  20. Effects of hypergravity on adipose-derived stem cell morphology, mechanical property and proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Tavakolinejad, Alireza [Medical Nanotechnology and Tissue Engineering Research Center, Taleghani Hospital, Shahid Beheshti University of Medical Sciences, Tehran (Iran, Islamic Republic of); Rabbani, Mohsen, E-mail: m.rabbani@eng.ui.ac.ir [Department of Biomedical Engineering, University of Isfahan, Isfahan (Iran, Islamic Republic of); Janmaleki, Mohsen [Medical Nanotechnology and Tissue Engineering Research Center, Taleghani Hospital, Shahid Beheshti University of Medical Sciences, Tehran (Iran, Islamic Republic of)

    2015-08-21

    Alteration in specific inertial conditions can lead to changes in morphology, proliferation, mechanical properties and cytoskeleton of cells. In this report, the effects of hypergravity on morphology of Adipose-Derived Stem Cells (ADSCs) are indicated. ADSCs were repeatedly exposed to discontinuous hypergravity conditions of 10 g, 20 g, 40 g and 60 g by utilizing centrifuge (three times of 20 min exposure, with an interval of 40 min at 1 g). Cell morphology in terms of length, width and cell elongation index and cytoskeleton of actin filaments and microtubules were analyzed by image processing. Consistent changes observed in cell elongation index as morphological change. Moreover, cell proliferation was assessed and mechanical properties of cells in case of elastic modulus of cells were evaluated by Atomic Force Microscopy. Increase in proliferation and decrease in elastic modulus of cells are further results of this study. Staining ADSC was done to show changes in cytoskeleton of the cells associated to hypergravity condition specifically in microfilament and microtubule components. After exposing to hypergravity, significant changes were observed in microfilaments and microtubule density as components of cytoskeleton. It was concluded that there could be a relationship between changes in morphology and MFs as the main component of the cells. - Highlights: • Hypergravity (10 g, 20 g, 40 g and 60 g) affects on adipose derived stem cells (ADSCs). • ADSCs after exposure to the hypergravity are more slender. • The height of ADSCs increases in all test groups comparing their control group. • Hypergravity decreases ADSCs modulus of elasticity and cell actin fiber content. • Hypergravity enhances proliferation rate of ADSCs.

  1. Effect of Manganese on the Mechanical Properties of Welded As-Cast Aluminium Joint

    Directory of Open Access Journals (Sweden)

    Isiaka Oluwole OLADELE

    2013-11-01

    Full Text Available The effects of manganese on the mechanical properties of welded and un-weld as-cast 6063 aluminium alloy has been studied. Alloys of varying percentage of manganese from 0.019 to 0.24 were sand cast. A wooden pattern of dimensions 200×100×100mm was used, the aluminium (500g was charged into an induction furnace and heated to 750°C for 15 minutes, this was followed by the addition of weighed powdered manganese, stirred and heated at the same temperature for another 5 minutes and thereafter poured into the already prepared sand mould at a temperature of 690°C. The as-cast aluminium samples, were sectioned into two equal parts of 45mm each using power hack saw; a weld groove was created between the sides of the samples using an electric hand grinding machine, the groove served as the path along which the filler metal was deposited on the aluminium, a single v butt joint was produced from each sample and Metal Inert Gas Welding process was carried out to produce the required joint design. The different cast samples were machined to the different test pieces after which they were assessed to determine their mechanical properties (impact, hardness (welded joint and heat affected zone and tensile tests. The microstructures of the welded samples were also studied. From the results, it was observed that Sample F, which has 0.172% Mn, has the best hardness and impact strength while sample C with 0.160% Mn has the highest ultimate tensile strength.

  2. Effects of hypergravity on adipose-derived stem cell morphology, mechanical property and proliferation

    International Nuclear Information System (INIS)

    Tavakolinejad, Alireza; Rabbani, Mohsen; Janmaleki, Mohsen

    2015-01-01

    Alteration in specific inertial conditions can lead to changes in morphology, proliferation, mechanical properties and cytoskeleton of cells. In this report, the effects of hypergravity on morphology of Adipose-Derived Stem Cells (ADSCs) are indicated. ADSCs were repeatedly exposed to discontinuous hypergravity conditions of 10 g, 20 g, 40 g and 60 g by utilizing centrifuge (three times of 20 min exposure, with an interval of 40 min at 1 g). Cell morphology in terms of length, width and cell elongation index and cytoskeleton of actin filaments and microtubules were analyzed by image processing. Consistent changes observed in cell elongation index as morphological change. Moreover, cell proliferation was assessed and mechanical properties of cells in case of elastic modulus of cells were evaluated by Atomic Force Microscopy. Increase in proliferation and decrease in elastic modulus of cells are further results of this study. Staining ADSC was done to show changes in cytoskeleton of the cells associated to hypergravity condition specifically in microfilament and microtubule components. After exposing to hypergravity, significant changes were observed in microfilaments and microtubule density as components of cytoskeleton. It was concluded that there could be a relationship between changes in morphology and MFs as the main component of the cells. - Highlights: • Hypergravity (10 g, 20 g, 40 g and 60 g) affects on adipose derived stem cells (ADSCs). • ADSCs after exposure to the hypergravity are more slender. • The height of ADSCs increases in all test groups comparing their control group. • Hypergravity decreases ADSCs modulus of elasticity and cell actin fiber content. • Hypergravity enhances proliferation rate of ADSCs

  3. Effect of resin composition to the electrical and mechanical properties of high voltage insulator material

    International Nuclear Information System (INIS)

    Totok Dermawan; Elin Nuraini; Suyamto

    2012-01-01

    A solid insulator manufacture of resins for high voltage with a variation of resin and hardener composition has been made. The purpose of research to know electrical and mechanical properties of high voltage insulator material of resin. To determine its electric properties, the material is tested its breakdown voltage and the flashover voltage that occurred on the surface. While to determine the mechanical properties were tested by measuring its strength with a tensile test. From testing with variety of mixed composition it is known that for composition between hardener and resin of 1 : 800 has most advantageous properties because it has good strength with a tensile strength of 19.86 MPa and enough high dielectric strength of 43.2 kV / mm). (author)

  4. Effect of fabrication process on physical and mechanical properties of tungsten carbide - cobalt composite: A review

    Science.gov (United States)

    Mahaidin, Ahmad Aswad; Jaafar, Talib Ria; Selamat, Mohd Asri; Budin, Salina; Sulaiman, Zaim Syazwan; Hamid, Mohamad Hasnan Abdul

    2017-12-01

    WC-Co, which is also known as cemented carbide, is widely used in metal cutting industry and wear related application due to their excellent mechanical properties. Manufacturing industries are focusing on improving productivity and reducing operational cost with machining operation is considered as one of the factors. Thus, machining conditions are becoming more severe and required better cutting tool bit with improved mechanical properties to withstand high temperature operation. Numerous studies have been made over the generation for further improvement of cemented carbide properties to meet the constant increase in demand. However, the results of these studies vary due to different process parameters and manufacturing technology. This paper summarizes the studies to improve the properties of WC-Co composite using different consolidation (powder size, mixing method, formulation, etc) and sintering parameters (temperature, time, atmosphere, etc).

  5. Effects of alkali and steaming on mechanical properties of snake fruit (Salacca) fiber

    Science.gov (United States)

    Darmanto, Seno; Rochardjo, Heru S. B.; Jamasri, Widyorini, Ragil

    2017-01-01

    The aim of this research is to investigate the effect of alkali treatment and steaming on mechanical properties of Snake Fruit frond fiber. The presence of surface impurities and a lot of hydroxyl groups makes natural fiber less compatible for composite materials reinforcement. Efforts to remove the impurities can be done by physical, chemical and mechanical treatments. This paper reports the treatment of Snake Fruit frond single fiber by subjecting it to alkali treatments with 2%- 8% NaOH for 2 - 6 hours at room temperature. The treatment is then followed by steaming at a pressure of 2 bars in 1 hour. Results show that the treatment of alkali and the alkali-steaming combination can increase cellulose percentage. The tensile tests show that this type of treatment in combination resulted in the higher tensile strength compared to untreated fiber. There is a significant increase in tensile strength with increasing alkali percentage. However, the further increase in the percentage of alkali solution will result in decreasing tensile strength. The highest value of tensile strength after treatment was 275 MPa with 6 hours treatment at alkali percentage of 2 %.

  6. The effect of Cu on mechanical and precipitation properties of Al-Zn-Mg alloys

    International Nuclear Information System (INIS)

    Chinh, N.Q.; Lendvai, J.; Ping, D.H.; Hono, K.

    2004-01-01

    The effect of Cu on the mechanical and precipitation properties of a high strength Al-2.4 at.% Zn-2.1 at.% Mg alloy was investigated by compression and indentation tests, as well as by differential scanning calorimetry (DSC), transmission electron microscopy (TEM) and three-dimensional atom probe field ion microscopy (3DAPFIM). The addition of 0.5 at.% Cu introduces significant changes in the precipitation process and consequently in the age-hardening behavior of the alloy. Microstructural measurements reveal that the addition of Cu changes the density of GP zones, but it also changes partly the shape and composition of the particles. Mechanical and microstructural results together lead to the conclusion that clustering of solute atoms and vacancies during or immediately after water quenching plays an important role in the nucleation of intermediate phase precipitates in one-step aging and the addition of Cu to ternary Al-Zn-Mg leads to changes also in the initial clustering process

  7. Effect of grain orientation and heat treatment on mechanical properties of pure W

    Energy Technology Data Exchange (ETDEWEB)

    Noto, Hiroyuki, E-mail: noto_hiroyuki@iae.kyoto-u.ac.jp [Graduate School of Energy Science, Kyoto University, Kyoto 611-0011 (Japan); Research Fellow of Japan Society for the Promotion of Science (Japan); Taniguchi, Shuichi [Graduate School of Energy Science, Kyoto University, Kyoto 611-0011 (Japan); Kurishita, Hiroaki; Matsuo, Satoru [International Research Center for Nuclear Materials Science, Institute for Materials Research, Tohoku University, Oarai, Ibaraki 311-1313 (Japan); Ukita, Takashi; Tokunaga, Kazutoshi [Institute for Applied Mechanics, Kyushu University, Kasuga, Fukuoka 816-8580 (Japan); Kimura, Akihiko [Institute of Advanced Energy, Kyoto University, Kyoto 611-0011 (Japan)

    2014-12-15

    The effect of grain orientation, heat-treatment temperature and test temperature on the mechanical properties of tungsten (W), which vary depending on plastic working and fabrication process, was investigated by mechanical testing of tensile or bending. Heavily worked W samples (1.5–2.0 mm in the final thickness) exhibit degradation of fracture strength due to recrystallization embrittlement after heat-treatment at 1240 °C (temperature of diffusion bonding between W and a candidate material of the Fe base support structure). On the other hand, W samples with lower thickness reduction rates do not suffer degradation of fracture strength after heating up to around 1300 °C, and show somewhat higher fracture strength by heat-treatment below 1300 °C than the samples in the as-received state. The observed behavior is a reflection of recovery of dislocations introduced by plastic working. High temperature tensile testing of ITER grade W with an anisotropic grain structure and S-TUN with an equiaxed grain structure revealed that both W grades exhibit plastic elongation at temperatures higher than 200 °C with essentially the same temperature dependence of yield strength, which is relatively insensitive to grain orientation in the structure at 200–1300 °C.

  8. Effect of grain orientation and heat treatment on mechanical properties of pure W

    International Nuclear Information System (INIS)

    Noto, Hiroyuki; Taniguchi, Shuichi; Kurishita, Hiroaki; Matsuo, Satoru; Ukita, Takashi; Tokunaga, Kazutoshi; Kimura, Akihiko

    2014-01-01

    The effect of grain orientation, heat-treatment temperature and test temperature on the mechanical properties of tungsten (W), which vary depending on plastic working and fabrication process, was investigated by mechanical testing of tensile or bending. Heavily worked W samples (1.5–2.0 mm in the final thickness) exhibit degradation of fracture strength due to recrystallization embrittlement after heat-treatment at 1240 °C (temperature of diffusion bonding between W and a candidate material of the Fe base support structure). On the other hand, W samples with lower thickness reduction rates do not suffer degradation of fracture strength after heating up to around 1300 °C, and show somewhat higher fracture strength by heat-treatment below 1300 °C than the samples in the as-received state. The observed behavior is a reflection of recovery of dislocations introduced by plastic working. High temperature tensile testing of ITER grade W with an anisotropic grain structure and S-TUN with an equiaxed grain structure revealed that both W grades exhibit plastic elongation at temperatures higher than 200 °C with essentially the same temperature dependence of yield strength, which is relatively insensitive to grain orientation in the structure at 200–1300 °C

  9. Effect of fast freeze-thaw cycles on mechanical properties of ordinary-air-entrained concrete.

    Science.gov (United States)

    Shang, Huai-shuai; Cao, Wei-qun; Wang, Bin

    2014-01-01

    Freezing-thawing resistance is a very significant characteristic for concrete in severe environment (such as cold region with the lowest temperature below 0°C). In this study, ordinary-air-entrained (O-A-E) concrete was produced in a laboratory environment; the compressive strength, cubic compressive strength of C50, C40, C30, C25, and C20 ordinary-air-entrained concrete, tensile strength, and cleavage strength of C30 ordinary-air-entrained concrete were measured after fast freeze-thaw cycles. The effects of fast freeze-thaw cycles on the mechanical properties (compressive strength and cleavage strength) of ordinary-air-entrained concrete materials are investigated on the basis of the experimental results. And the concise mathematical formula between mechanical behavior and number of fast freeze-thaw cycles was established. The experiment results can be used as a reference in design, maintenance, and life prediction of ordinary-air-entrained concrete structure (such as dam, offshore platform, etc.) in cold regions.

  10. Experimental Investigation into Corrosion Effect on Mechanical Properties of High Strength Steel Bars under Dynamic Loadings

    Directory of Open Access Journals (Sweden)

    Hui Chen

    2018-01-01

    Full Text Available The tensile behaviors of corroded steel bars are important in the capacity evaluation of corroded reinforced concrete structures. The present paper studies the mechanical behavior of the corroded high strength reinforcing steel bars under static and dynamic loading. High strength reinforcing steel bars were corroded by using accelerated corrosion methods and the tensile tests were carried out under different strain rates. The results showed that the mechanical properties of corroded high strength steel bars were strain rate dependent, and the strain rate effect decreased with the increase of corrosion degree. The decreased nominal yield and ultimate strengths were mainly caused by the reduction of cross-sectional areas, and the decreased ultimate deformation and the shortened yield plateau resulted from the intensified stress concentration at the nonuniform reduction. Based on the test results, reduction factors were proposed to relate the tensile behaviors with the corrosion degree and strain rate for corroded bars. A modified Johnson-Cook strength model of corroded high strength steel bars under dynamic loading was proposed by taking into account the influence of corrosion degree. Comparison between the model and test results showed that proposed model properly describes the dynamic response of the corroded high strength rebars.

  11. Reactor irradiation and helium-3 effects on mechanical properties of alpha-titanium alloys

    International Nuclear Information System (INIS)

    Tebus, V.N.; Alekseev, Eh.F.; Golikov, I.V.

    1990-01-01

    Dependence of α-titanium alloy mechanical properties on test temperature and neutron fluence is investigated. Irradiation is shown to result in material hardening and in their plasticity reduction, but residual plasticity remains rather high. Additional reduction of plasticity results in helium-3 introduced in materials under irradiation. Restoration of properties is observed at test temperature higher 500 deg C. Irradiation by fast neutrons up to high fluences (1.4·10 23 cm -2 ) results in essential alloy softening

  12. Effects of asphalt rejuvenator on thermal and mechanical properties on oxidized hot mixed asphalt pavements

    Science.gov (United States)

    Farace, Nicholas A.; Buttlar, William G.; Reis, Henrique

    2016-04-01

    The utilization of asphalt rejuvenator, and its effectiveness for restoring thermal and mechanical properties was investigated via Disk-shaped Compact Tension (DC(T)) and acoustic emission (AE) testing for determining mechanical properties and embrittlement temperatures of the mixtures. During the DC(T) testing the fracture energies and peak loads were used to measure the resistance of the rejuvenated asphalt to low temperature cracking. The AE testing monitored the acoustic emission activity while the specimens were cooled from room temperature to -40 °C to estimate the temperature at which thermal cracking began (i.e. the embrittlement temperature). First, a baseline response was obtained by obtaining the mechanical and thermal response of virgin HMA samples and HMA samples that had been exposed to oxidative aging for 36 hours at 135°C. The results showed the virgin samples had much higher peak loads and fracture energies than the 36 hours aged samples. Acoustic Emission showed similar results with the virgin samples having embrittlement temperatures 10 °C cooler than the 36 hours aged specimens. Then, overaged for 36 hours specimens were treated different amounts of rejuvenator (10%, 15%, and 20% by weight of binder content) and left to dwell for increased amount of time periods varying from one to eight weeks. It was observed that the AE results showed an improvement of embrittlement temperature with increasing with the dwell times. The 8 weeks specimens had cooler embrittlement temperatures than the virgin specimens. Finally, the low temperature effects on fracture energy and peak load of the rejuvenated asphalt was investigated. Rejuvenator was applied (10% by weight of binder) to specimens aged 36 hours at 135 °C, and the dwell time was varied from 1 to 4 weeks. The results showed that the peak loads were restored to levels of the virgin specimens, and the fracture energies improved to levels beyond that of the virgin specimens. The results also showed a

  13. The Effect of Irradiation on Mechanical and Thermal Properties of Selected Types of Polymers

    Directory of Open Access Journals (Sweden)

    David Manas

    2018-02-01

    Full Text Available This article deals with the influence of electron-beam radiation on the micro-mechanical, thermo-mechanical, and structural properties of selected polymers. In the search for the desired improvement of polymers, it is possible to use, inter alia, one particular possible modification—Namely, crosslinking—Which is a process during which macromolecular chains start to connect to each other and, thus, create the spatial network in the structure. In the course of the treatment of the ionizing radiation, two actions can occur: crosslinking and scission of macromolecules, or degradation. Both these processes run in parallel. Using the crosslinking technology, standard and technical polymers can acquire the more “expensive” high-tech polymeric material properties and, thus, replace these materials in many applications. The polymers that were tested were selected from across the whole spectra of thermoplastics, ranging from commodity polymers, technical polymers, as well as high-performance polymers. These polymers were irradiated by different doses of beta radiation (33, 66, 99, 132, 165, and 198 kGy. The micro-mechanical and thermo-mechanical properties of these polymers were measured. When considering the results, it is obvious that irradiation acts on each polymer differently but, always when the optimal dose was found, the mechanical properties increased by up to 36%. The changes of micro-mechanical and thermo-mechanical properties were confirmed by structural measurement when the change of the micro-hardness and modulus corresponded to the crystalline phase change as determined by X-ray and gel content.

  14. Effect of heat treatments on precipitate microstructure and mechanical properties of CuCrZr alloy

    OpenAIRE

    Singh, B.N; Edwards, D.J.; Tähtinen, S.

    2004-01-01

    A number of specimens of CuCrZr alloy was prime aged and then overaged at 600oC for 1, 2 and 4 hours and for 4 hours at 700 and 850oC. After different heat treatments, both the precipitate microstructure and mechanical properties were characterized.Mechanical properties were determined at 50 and 300oC. Some selected specimens in the prime aged as well as overaged conditions were irradiated in the BR-2 reactor at Mol at 60 and 300oC to a displacement dose level of ~0.3 dpa. Irradiated specimen...

  15. Effect of Zn addition on microstructure and mechanical properties of an Al–Mg–Si alloy

    Directory of Open Access Journals (Sweden)

    Lizhen Yan

    2014-04-01

    Full Text Available In the present work, an Al–0.66Mg–0.85Si–0.2Cu alloy with Zn addition was investigated by electron back scattering diffraction (EBSD, high resolution electron microscopy (HREM, tensile and Erichsen tests. The mechanical properties of the alloy after pre-aging met the standards of sheet forming. After paint baking, the yield strength of the alloy was improved apparently. GP(II zones and ηʹ phases were formed during aging process due to Zn addition. With the precipitation of GP zones, β″ phases, GP(II zones and ηʹ phases, the alloys displayed excellent mechanical properties.

  16. Mechanical Properties of Composite Materials

    Directory of Open Access Journals (Sweden)

    Mitsuhiro Okayasu

    2014-10-01

    Full Text Available An examination has been made of the mechanical and failure properties of several composite materials, such as a short and a long carbon fiber reinforced plastic (short- and long-CFRP and metal based composite material. The short CFRP materials were used for a recycled CFRP which fabricated by the following process: the CFRP, consisting of epoxy resin with carbon fiber, is injected to a rectangular plate cavity after mixing with acrylonitrile butadiene styrene resin with different weight fractions of CFRP. The fatigue and ultimate tensile strength (UTS increased with increasing CFRP content. These correlations, however, break down, especially for tensile strength, as the CFPR content becomes more than 70%. Influence of sample temperature on the bending strength of the long-CFRP was investigated, and it appears that the strength slightly degreases with increasing the temperature, due to the weakness in the matrix. Broken fiber and pull-out or debonding between the fiber and matrix were related to the main failure of the short- and long-CFRP samples. Mechanical properties of metal based composite materials have been also investigated, where fiber-like high hardness CuAl2 structure is formed in aluminum matrix. Excellent mechanical properties were obtained in this alloy, e.g., the higher strength and the higher ductility, compared tothe same alloy without the fiber-like structure. There are strong anisotropic effects on the mechanical properties due to the fiber-like metal composite in a soft Al based matrix.

  17. The Effect of Mineral Powders Derived From Industrial Wastes on Selected Mechanical Properties of Concrete

    Science.gov (United States)

    Galińska, Anna; Czarnecki, Sławomir

    2017-10-01

    In recent years, concrete has been the most popular construction material. The main component of the concrete is cement. However, its production and transport causes significant emissions of CO2. Reports in the literature show that many laboratories are attempting to modify the composition of the concrete using various additives. These attempts are primarily designed to eliminate parts of cement. The greater part of the cement will be replaced with the selected additive, the more significant is the economic and ecological effect. Most attempts are related to the replacement of the selected additive in an amount of from 10 to 30% by weight of cement. Mineral powders, which are waste material producing crushed aggregate, are increasingly used for this purpose. Management of the waste carries significant cost related to their storage and disposal. With this in mind, the aim of this study was to evaluate the effect of mineral powders derived from industrial wastes on selected mechanical properties of concrete. In particular, the aim was to determine the effect of quartz and quartz-feldspar powders. For this purpose, 40, 50, 60% by weight of the cement was replaced by the selected powders. The results obtained were analysed and compared with previous attempts to replace the selected additive in an amount of from 10 to 30% by weight of cement.

  18. Effect of sewage wastes on the physico-mechanical properties of cement and reinforced steel

    Directory of Open Access Journals (Sweden)

    Magdy A. Abd El-Aziz

    2013-09-01

    Full Text Available The aggressive chemical attack due to salt water is one of many factors affecting the concrete deterioration. This effect includes corrosion of concrete and steel due to the exposure to the aggressive natural or artificial chemicals such as ammonia and ammonium salts. Ammonia is one of the compounds substantially in each of the remnants of sanitation plants, industrial or service of some units within building industrial waste. This work aims to study the effect of different concentrations of ammonia in the popular image on the physical, chemical and mechanical properties of different types of cement such as SRC; OPC and HSC. The electrochemical measurement (linear polarization systems as well as infrared spectroscopy (IR were used in this study. The behaviour of reinforced steel embedded in SRC; OPC and HSC with (5 wt.% ammonium sulphate solution were determined. The results show that ammonia gets a harmful effect on OPC and SRC mortars but HSC shows high resistivity. Also, the reinforced steel is greatly affected in the aggressive medium containing ammonium solution.

  19. Effect of Fe-Content on the Mechanical Properties of Recycled Al Alloys during Hot Compression

    Directory of Open Access Journals (Sweden)

    Hongzhou Lu

    2017-07-01

    Full Text Available It is unavoidable that Fe impurities will be mixed into Al alloys during recycling of automotive aluminum parts, and the Fe content has a significant effect on the mechanical properties of the recycled Al alloys. In this work, hot compression tests of two Fe-containing Al alloys were carried out at elevated temperatures within a wide strain rate range from 0.01 s−1 to 10 s−1. The effect of Fe content on the peak stress of the stress vs. strain curves, strain rate sensitivity and activation energy for dynamic recrystallization are analyzed. Results show that the recycled Al alloy containing 0.5 wt % Fe exhibits higher peak stresses and larger activation energy than the recycled Al alloy containing 0.1 wt % Fe, which results from the fact that there are more dispersed AlMgFeSi and/or AlFeSi precipitates in the recycled Al alloy containing 0.5 wt % Fe as confirmed by SEM observation and energy spectrum analysis. It is also shown that the Fe content has little effect on the strain rate sensitivity of the recycled Al alloys.

  20. Effect of metallic dopants on the microstructure and mechanical properties of TiB2

    Czech Academy of Sciences Publication Activity Database

    Chlup, Zdeněk; Bača, L.; Halasová, Martina; Neubauer, E.; Hadraba, Hynek; Stelzer, N.; Roupcová, Pavla

    2015-01-01

    Roč. 35, č. 10 (2015), s. 2745-2754 ISSN 0955-2219 R&D Projects: GA ČR(CZ) GAP108/11/1644; GA MŠk(CZ) ED1.1.00/02.0068 Grant - others:The Austrian Research Promotion Agency (FFG)(AT) 834287 Institutional support: RVO:68081723 Keywords : Titanium diboride * Metallic dopants * Microstructure * Mechanical properties * Fracture behaviour1 Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 2.933, year: 2015

  1. Numerical Investigation of Thermal and Thermo-mechanical Effective Properties for Short Fibre Reinforced Composite

    Science.gov (United States)

    Ioannou, Ioannis; Hodzic, Alma; Gitman, Inna M.

    2017-10-01

    This study aims to investigate the thermal conductivity and the linear coefficient of thermal expansion for short fibre reinforced composites. The study combines numerical and statistical analyses in order to primarily examine the representative size and the effective properties of the volume element. Effects of various micromechanical parameters, such as fibre's aspect ratio and fibre's orientation, on the minimum representative size are discussed. The numerically acquired effective properties, obtained for the representative size, are presented and compared with analytical models.

  2. Mechanical properties of irradiated materials

    International Nuclear Information System (INIS)

    Robertson, I.M.; Robach, J.; Wirth, B.

    2001-01-01

    The effect of irradiation on the mechanical properties of metals is considered with particular attention being paid to the development of defect-free channels following uniaxial tensile loading. The in situ transmission electron microscope deformation technique is coupled with dislocation dynamic computer simulations to reveal the fundamental processes governing the elimination of defects by glissile dislocations. The observations of preliminary experiments are reported.(author)

  3. Effects of non-linearity of material properties on the coupled mechanical-hydraulic-thermal behavior in rock mass

    International Nuclear Information System (INIS)

    Kobayashi, Akira; Ohnishi, Yuzo

    1986-01-01

    The nonlinearity of material properties used in the coupled mechanical-hydraulic-thermal analysis is investigated from the past literatures. Some nonlinearity that is respectively effective for the system is introduced into our computer code for analysis such a coupling problem by using finite element method. And the effects of nonlinearity of each material property on the coupled behavior in rock mass are examined for simple model and Stripa project model with the computer code. (author)

  4. Effect of Nb on magnetic and mechanical properties of TbDyFe alloys

    Science.gov (United States)

    Wang, Naijuan; Liu, Yuan; Zhang, Huawei; Chen, Xiang; Li, Yanxiang

    2018-03-01

    The intrinsic brittleness in giant magnetostrictive material TbDyFe alloy has devastating influence on the machinability and properties of the alloy, thus affecting its applications. The purpose of this paper is to study the mechanical properties of the TbDyFe alloy by alloying with Nb element. The samples (Tb0.3Dy0.7)xFe2xNby (y = 0, 0.01, 0.04, 0.07, 0.1; 3x + y = 1) were melted in an arc melting furnace under high purity argon atmosphere. The microstructure, magnetostrictive properties and mechanical performance of the alloys were studied systematically. The results showed that NbFe2 phases were observed in the alloys with the addition of Nb. Moreover, both the NbFe2 phases and rare earth (RE)-rich phases were increased with the increasing of Nb element. The mechanical properties results revealed that the fracture toughness of the alloy with the addition of Nb enhanced 1.5-5 times of the Nb-free alloy. Both the NbFe2 phase and the RE-rich phase had the ability to prevent crack propagation, so that they can strengthen the REFe2 body. However, NbFe2 phase is a paramagnetic phase, which can reduce the magnetostrictive properties of the alloy by excessive precipitation.

  5. Effect of compression pressure on mechanical and electrical properties of polyaniline pellets

    Czech Academy of Sciences Publication Activity Database

    Valentová, H.; Prokeš, J.; Nedbal, J.; Stejskal, Jaroslav

    2013-01-01

    Roč. 67, č. 8 (2013), s. 1109-1112 ISSN 0366-6352 R&D Projects: GA TA ČR TE01020022 Institutional support: RVO:61389013 Keywords : conducting polymer * hardness * mechanical properties Subject RIV: CG - Electrochemistry Impact factor: 1.193, year: 2013

  6. Effect of kenaf short fiber loading on mechanical properties of biocomposites

    Science.gov (United States)

    Andilolo, J.; Nikmatin, S.; Nugroho, N.; Alatas, H.; Wismogroho, A. S.

    2017-05-01

    The research of biocomposite product with kenaf (Hibiscus cannabinus) short fiber as a filler and Acrylonitrile Butadiene Styrene (ABS) as the matrix had been done to understand the mechanical properties of this material. Kenaf short fiber was obtained from mechanical sieving after doing the mechanical milling. TAPPI method has been done to determine the chemical properties. In order to form a granular biocomposite a single screw extruder was performed with a variation of particle loading 10 and 15%. The original of acrylonitrile butadiene styrene (ABS) has been used as matrix. The fabrication of speciment had been done by molding injection process. Mechanical properties test was done by ASTM standarization. The results showed the density of the fibers of 1.008 g/cm3 with a fiber length of 897.07 µm and a diameter of 66.38 µm. Tensile strength of kenaf short fiber loading 10 and 15% was 23.522 ± 8.36 MPa and 20.739 ± 6.79 MPa, respectively. The tensile properties showed a decreasing trend as the fiber loading was increased. The values of impact strength were 68.657 ± 4.89 kJ m-2 and 82.090 ± 5.56 kJ m-2, respectively and the hardness values were 96.60 ± 6.03 HR and 105.20 ± 13.17 HR, respectively. Kenaf fiber can be a good reinforcement candidate for high performance polymer bio-composites.

  7. Effect of vibrating drawing on the mechanical properties of tungsten wire

    International Nuclear Information System (INIS)

    Shapoval, A.N.; Izotov, V.M.; Mosolev, V.D.

    1986-01-01

    Mechanical properties of tungsten wire produced according to different versions of drawing are investigated. It is established that a wire produced by means of drawing through two draw plates vibrating in contrast phases possesses a lower (by 90 %) ultimate strength and a higher (by 10 %) ductility characteristic as compared with a wire produced without vibration

  8. Effect of water absorption on mechanical properties of flax fibre reinforced composites

    CSIR Research Space (South Africa)

    Guduri, BBR

    2007-01-01

    Full Text Available Scutched and line flax fibres, with mean linear density of about 19.5 decitex, were utilized for this study. Mechanical properties of fibre and resin were measured for assessing their contribution in the composite matrix. Polypropylene (PP)/ short...

  9. Effects of mechanical strain on optical properties of ZnO nanowire

    Directory of Open Access Journals (Sweden)

    Ali Vazinishayan

    2018-02-01

    Full Text Available The main objective of this study is to investigate the influences of mechanical strain on optical properties of ZnO nanowire (NW before and after embedding ZnS nanowire into the ZnO nanowire, respectively. For this work, commercial finite element modeling (FEM software package ABAQUS and three-dimensional (3D finite-difference time-domain (FDTD methods were utilized to analyze the nonlinear mechanical behavior and optical properties of the sample, respectively. Likewise, in this structure a single focused Gaussian beam with wavelength of 633 nm was used as source. The dimensions of ZnO nanowire were defined to be 12280 nm in length and 103.2 nm in diameter with hexagonal cross-section. In order to investigate mechanical properties, three-point bending technique was adopted so that both ends of the model were clamped with mid-span under loading condition and then the physical deformation model was imported into FDTD solutions to study optical properties of ZnO nanowire under mechanical strain. Moreover, it was found that increase in the strain due to the external load induced changes in reflectance, transmittance and absorptance, respectively.

  10. Effects of recrystallization annealing on mechanical properties of cold-rolled PdNi5 wires

    Directory of Open Access Journals (Sweden)

    Aleksandra Ivanović

    2016-03-01

    Full Text Available The aim of this investigation was to determine the influence of the recrystallization temperature and recrystallization time on the microstructure and mechanical properties of the PdNi5 alloy subjected to cold deformation in the process of rolling at a constant deformation degree. The samples of PdNi5 alloy were recrystallization annealed within the temperature range of 200-1000ºC and annealing time range of 20-45 min after cold rolling with deformation degree of 97%. The tensile test was carried out using universal material testing machine. The hardness was also measured on the combined device for measuring Vickers and Brinell hardness. Metallographic observations were performed on an optical microscope. The analysis of the results of investigations regarding the microstructural changes and corresponding mechanical properties of cold-rolled PdNi5 strips shows that annealing temperature of 500ºC was sufficient to activate the energy for various recrystallization processes causing a change in the mechanical properties of cold-rolled PdNi5 strips. The annealing time, at constant annealing temperature, almost did not affect a recrystallization temperature and the mechanical properties of the cold-rolled PdNi5 strips.

  11. Effect of particles size on mechanical properties of polypropylene particulate composites

    Czech Academy of Sciences Publication Activity Database

    Nezbedová, E.; Krčma, F.; Majer, Z.; Hutař, Pavel

    2016-01-01

    Roč. 7, č. 5 (2016), s. 690-699 ISSN 1757-9864 Institutional support: RVO:68081723 Keywords : Morphology * Mechanical properties * Numerical simulation * Polypropylene particulate composite s * Plasma surface treatment Subject RIV: JI - Composite Material s www.emeraldinsight.com/1757-9864.htm

  12. Effects of mechanical strain on optical properties of ZnO nanowire

    Science.gov (United States)

    Vazinishayan, Ali; Lambada, Dasaradha Rao; Yang, Shuming; Zhang, Guofeng; Cheng, Biyao; Woldu, Yonas Tesfaye; Shafique, Shareen; Wang, Yiming; Anastase, Ndahimana

    2018-02-01

    The main objective of this study is to investigate the influences of mechanical strain on optical properties of ZnO nanowire (NW) before and after embedding ZnS nanowire into the ZnO nanowire, respectively. For this work, commercial finite element modeling (FEM) software package ABAQUS and three-dimensional (3D) finite-difference time-domain (FDTD) methods were utilized to analyze the nonlinear mechanical behavior and optical properties of the sample, respectively. Likewise, in this structure a single focused Gaussian beam with wavelength of 633 nm was used as source. The dimensions of ZnO nanowire were defined to be 12280 nm in length and 103.2 nm in diameter with hexagonal cross-section. In order to investigate mechanical properties, three-point bending technique was adopted so that both ends of the model were clamped with mid-span under loading condition and then the physical deformation model was imported into FDTD solutions to study optical properties of ZnO nanowire under mechanical strain. Moreover, it was found that increase in the strain due to the external load induced changes in reflectance, transmittance and absorptance, respectively.

  13. Investigation of combined effect of mixture variables on mechanical properties of cement treated demolition waste

    NARCIS (Netherlands)

    Xuan, D.; Houben, L.J.M.; Molenaar, A.A.A.; Shui, Z.

    2012-01-01

    One of high efficient ways to reuse the recycled construction and demolition waste (CDW) is to consider it as a road base material. The recycled CDW however is mainly a mix of recycled masonry and concrete with a wide variation in composition. This results that the mechanical properties of cement

  14. Effect of ion irradiation on the surface, structural and mechanical properties of brass

    Science.gov (United States)

    Ahmad, Shahbaz; Bashir, Shazia; Ali, Nisar; Umm-i-Kalsoom; Yousaf, Daniel; Faizan-ul-Haq; Naeem, Athar; Ahmad, Riaz; Khlaeeq-ur-Rahman, M.

    2014-04-01

    Modifications to the surface, structural and mechanical properties of brass after ion irradiation have been investigated. Brass targets were bombarded by carbon ions of 2 MeV energy from a Pelletron linear accelerator for various fluences ranging from 56 × 1012 to 26 × 1013 ions/cm2. A scanning electron microscope and X-ray diffractometer were utilized to analyze the surface morphology and crystallographic structure respectively. To explore the mechanical properties e.g., yield stress, ultimate tensile strength and microhardness of irradiated brass, an universal tensile testing machine and Vickers microhardness tester were used. Scanning electron microscopy results revealed an irregular and randomly distributed sputter morphology for a lower ion fluence. With increasing ion fluence, the incoherently shaped structures were transformed into dendritic structures. Nano/micro sized craters and voids, along with the appearance of pits, were observed at the maximum ion fluence. From X-ray diffraction results, no new phases were observed to be formed in the brass upon irradiation. However, a change in the peak intensity and higher and lower angle shifting were observed, which represents the generation of ion-induced defects and stresses. Analyses confirmed modifications in the mechanical properties of irradiated brass. The yield stress, ultimate tensile strength and hardness initially decreased and then increased with increasing ion fluence. The changes in the mechanical properties of irradiated brass are well correlated with surface and crystallographic modifications and are attributed to the generation, augmentation, recombination and annihilation of the ion-induced defects.

  15. The effect of water uptake on the mechanical properties of low-k organosilica glass

    Science.gov (United States)

    X. Guo; J.E. Jakes; M.T. Nichols; S. Banna; Y. Nishi; J.L. Shohet

    2013-01-01

    Water uptake in porous low-k dielectrics has become a significant challenge for both back-end-of line integration and circuit reliability. The influence of absorbed water on the mechanical properties of plasma-enhanced chemical-vapor-deposited organosilicate glasses (SiCOH) was investigated with nanoindentation. The roles of physisorbed (α-...

  16. Effect of overlap length on the mechanical properties of flake reinforced thermoplastic composites

    NARCIS (Netherlands)

    Abdul Rasheed, M. I.; van Hattum, F.W.J.; Rietman, B.; Visser, H. A.; Akkerman, R.

    2015-01-01

    The in-plane mechanical properties of laminates with two dimensional planar reinforcing elements (flakes in this case) are investigated. A woven structure for the flakes is considered in this study, comprising of fiber bundles in both warp and weft direction. Failure of the flake or the interface

  17. Effects of fire retardants on physical, mechanical, and fire properties of flat-pressed WPCs

    Science.gov (United States)

    Nadir Ayrilmis; Jan T. Benthien; Heiko Thoemen; Robert H. White

    2012-01-01

    Physical, mechanical, and fire properties of the flat-pressed wood plastic composites (WPCs) incorporated with various fire retardants (10% by weight) at different levels of wood flour (WF) content, 40, 50, or 60 wt%, were investigated. The WPC panels were made from dry-blended WF, polypropylene (PP), and fire retardant (FR) powders with maleic anhydride-grafted PP (2...

  18. Effect of track maintenance on mechanical properties of a dirt racetrack: a preliminary study.

    Science.gov (United States)

    Peterson, M L; McIlwraith, C W

    2008-09-01

    When Thoroughbred racehorses experience catastrophic injuries, the track surface is often discussed as a factor. The present study investigated the mechanical properties of the surface and found that significant changes in a track occur during routine maintenance. Questions regarding the relative importance of track variability and hardness require further investigation.

  19. Agrofibre reinforced poly(lactic acid) composites: Effect of moisture on degradation and mechanical properties

    NARCIS (Netherlands)

    Oever, van den M.J.A.; Beck, B.; Müssig, J.

    2010-01-01

    Natural fibre reinforced PLA composites are a 100% biobased material with a promising mechanical properties profile. However, natural fibres are hygroscopic whereas PLA is sensitive to hydrolytic degradation under melt processing conditions in the presence of small amounts of water. Here, we

  20. Effect of crumb rubber on the mechanical properties of crushed recycled pavement materials.

    Science.gov (United States)

    Li, Jie; Saberian, Mohammad; Nguyen, Bao Thach

    2018-07-15

    The low-carbon footprint of using recycled construction and demolition (C&D) aggregates in civil engineering infrastructure applications has been considered to be a significant solution for the replacement of conventional pavement aggregates. Investigations regarding the use of crumb rubber in the base and subbase layers of pavement have been well documented. However, information on the effects of crumb rubber and its size within C&D aggregates as the base/subbase layers is still very limited. In this study, crumb rubber with particle sizes ranging from 400 to 600 μm (fine) to 10-15 mm (coarse), 20 mm recycled crushed concrete (RCC), and 20 mm crushed rock (CR) were used. The crumb rubber was added to the two groups of C&D aggregates at 0.5, 1 and 2% by weight percentages of the aggregates. The effect of crumb rubber on the mechanical properties (such as California bearing ratio, unconfined compressive strength, aggregate crushing value, dynamic lightweight cone penetrometer, Clegg impact value, Los Angeles abrasion values, and resilient modulus) of the C&D aggregates was then examined. Based on the experimental test results, it was found that crumb rubber can be recycled as a waste material for the base and subbase layers in the pavement. Copyright © 2018 Elsevier Ltd. All rights reserved.

  1. Reactor irradiation effect on the physical-mechanical properties of zirconium carbides and niobium carbides

    International Nuclear Information System (INIS)

    Andrievskij, R.A.; Vlasov, K.P.; Shevchenko, A.S.; Lanin, A.G.; Pritchin, S.A.; Klyushin, V.V.; Kurushin, S.P.; Maskaev, A.S.

    1978-01-01

    A study has been made of the effect of the reactor radiation by a flux of neutrons 1.5x10 20 n/cm 2 (E>=1 meV) at radiation temperatures of 150 and 1100 deg C on the physico-mechanical properties of carbides of zirconium and niobium and their equimolar hard solution. A difference has been discovered in the behaviour of the indicated carbides under the effect of radiation. Under the investigated conditions of radiation the density of zirconium carbide is being decreased, while in the niobium carbide no actual volumetric changes occur. The increase of the lattice period in ZrC is more significant than in NbC. The electric resistance of ZrC is also changed more significantly than in the case of NbC, while for the microhardness a reverse relationship is observed. Strength and elasticity modulus change insignificantly in both cases. Resistance to crack formation shows a higher reduction for ZrC than for NbC, while the thermal strength shows an approximately similar increase. The equimolar hard solution of ZrC and NbC behaves to great extent similar to ZrC, although the change in electric resistance reminds of NbC while thermal strength changes differently. The study of the microstructure of the specimens has shown that radiation causes a large number of etching patterns-dislocations in NbC which are almost absent in ZrC

  2. Effects of crystal size on the mechanical properties of a lithium disilicate glass-ceramic

    Energy Technology Data Exchange (ETDEWEB)

    Li, D. [State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, 28 West Xianning Road, Xi’an 710049 (China); Guo, J.W.; Wang, X.S; Zhang, S.F. [State Key Laboratory of Military Stomatology, Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, 145 West Changle Road, Xi’an 710032 (China); He, L., E-mail: helin@mail.xjtu.edu.cn [State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, 28 West Xianning Road, Xi’an 710049 (China)

    2016-07-04

    Crystal size of lithium disilicate (LD) phase in a LD glass-ceramic was changed by thermally controlled crystallization of a precursory LD glass at different temperatures. Effects of the crystal size on the mechanical properties of the glass-ceramic were investigated. It was found that the flexural strength presented a hump-like variation trend with increasing the crystal size, the hardness monotonously decreased at the same time. It was further confirmed that micro residual compressive stresses existed inside the LD crystals due to the thermal expansion mismatch between the glass matrix and the crystalline phase. The levels of the residual stresses increased with increasing the crystal size. The crystal size performed dual effects on the flexural strength of the glass-ceramic: an “interlocking effect” caused by larger-sized LD crystals and a “micro residual stress effect” related to the balancing tensile stresses in the glass matrix. Higher residual tensile stresses in the glass matrix induced by larger-sized LD crystals would counteract the “interlocking effect” of the crystals, causing the strength degradation. The hardness of the glass-ceramic was mainly controlled by the “micro residual stress effect”.

  3. Effects of filter materials on microstructure and mechanical properties of AZ91

    Directory of Open Access Journals (Sweden)

    Wu Guohua

    2010-11-01

    Full Text Available The present investigation studied the effects of different kinds of ceramic foam filters (CFF incorporating gas bubbling on the microstructure and mechanical properties of virgin AZ91 alloys, and the reactions between filters and Mg melt during filtration. The results show that the purification process of CFF incorporating gas bubbling process can obviously improve the Rm and A of AZ91 alloy, especially the A. Amongst the selected four kinds of CFF, the MgO filter is the most suitable for filtrating Mg melt, and the filtration effective sequence of four kinds of filtrating materials is as follows: MgO>Al2O3>ZrO2>SiC. With MgO filter incorporating gas bubbling treatment under Ar flow rate of 2 L/min and temperature of 730 °C, the ultimate tensile strength Rm and elongation A can be improved greatly from 175.3 MPa and 2.74% to 195.4 MPa and 4.54%, respectively. No inclusions are found on the fracture surface of the sample filtrated by MgO ceramic foam filter, and the fracture mode is quasi-cleavage crack.

  4. Effects of deposited pyrolytic carbon on some mechanical properties of zircaloy-4 tubes. Vol. 3

    Energy Technology Data Exchange (ETDEWEB)

    Shrkawy, S W; Abdel-razek, I D; El-Sayed, H A [Metallurgy Department, Nuclear Research Center, Atomic Energy Authority, Cairo (Egypt)

    1996-03-01

    Zircaloy cladding tubes are not compatible with the uranium fuel pellets as they suffer from failure due to pelletclad interaction (PCI). A carbon coating, as used in the canadian CANLUB fuel elements, is thought to improve the cladding performance with respect to the PCI problem. In this paper pyrolytic carbon coating was deposited on zircaloy-4 cladding tubes by the thermal cracking of commercial butant gas at the temperature range 250-450 degree C. In order to evaluate the effect of gaseous species on the mechanical properties of the tubes tensile and microhardness testing measurements were performed on samples prepared from the coated tubes. The fractured surface of the tensile zircaloy tubes and the deposited carbon coating, both, were examined by the SEM. The results of the tensile tests of zircaloy-4 tubes indicated that the coating process has insignificant effect on the ultimate strength of the tubes tested. The values of Vickers hardness numbers were not significantly changed across the tubes thickness. The microstructure of deposited carbon, due to the cracking process, was granular in all the temperature range (250-450 degree C) studied. 9 figs., 1 tab.

  5. The effect of stimulated fission products on the structure and the mechanical properties of zircaloy

    International Nuclear Information System (INIS)

    Holub, F.

    1982-01-01

    The objective of investigation was to study the long-term effects of individual simulated fission products on the mechanical properties and the structure of Zircaloy. Tensile Test specimens of Zircaloy were annealed with important simulated fission products at 350 0 C up to 10,000 hours and at higher temperatures (500, 700 0 C) up to 2,000 hours. The principal methods of investigation on annealed Zircaloy specimens were tension tests at room temperature and at 400 0 C, scanning electron microscopy and microprobe technique, X-ray diffraction, X-ray fluorescence, optical metallography. The action of fission products at normal temperatures of reactor operation will give rise to a small enhancement of strength and a small drop of ductility of the fuel cladding material only. At high fuel pin temperatures which may be realized under abnormal operation conditions, some of the fission products potentially will produce detrimental consequences on the integrity of fuel pins. The most effective fission products will be: lanthanum oxide, followed by the earth alkaline oxides and the other rare earth oxides, molybdenum, iodine and cadmium

  6. Mechanical properties of ceramics

    CERN Document Server

    Pelleg, Joshua

    2014-01-01

    This book discusses the mechanical properties of ceramics and aims to provide both a solid background for undergraduate students, as well as serving as a text to bring practicing engineers up to date with the latest developments in this topic so they can use and apply these to their actual engineering work.  Generally, ceramics are made by moistening a mixture of clays, casting it into desired shapes and then firing it to a high temperature, a process known as 'vitrification'. The relatively late development of metallurgy was contingent on the availability of ceramics and the know-how to mold them into the appropriate forms. Because of the characteristics of ceramics, they offer great advantages over metals in specific applications in which hardness, wear resistance and chemical stability at high temperatures are essential. Clearly, modern ceramics manufacturing has come a long way from the early clay-processing fabrication method, and the last two decades have seen the development of sophisticated technique...

  7. Isolated and modulated effects of topology and material type on the mechanical properties of additively manufactured porous biomaterials.

    Science.gov (United States)

    Hedayati, R; Ahmadi, S M; Lietaert, K; Pouran, B; Li, Y; Weinans, H; Rans, C D; Zadpoor, A A

    2018-03-01

    In this study, we tried to quantify the isolated and modulated effects of topological design and material type on the mechanical properties of AM porous biomaterials. Towards this aim, we assembled a large dataset comprising the mechanical properties of AM porous biomaterials with different topological designs (i.e. different unit cell types and relative densities) and material types. Porous structures were additively manufactured from Co-Cr using a selective laser melting (SLM) machine and tested under quasi-static compression. The normalized mechanical properties obtained from those structures were compared with mechanical properties available from our previous studies for porous structures made from Ti-6Al-4V and pure titanium as well as with analytical solutions. The normalized values of elastic modulus and yield stress were found to be relatively close to each other as well as in agreement with analytical solutions regardless of material type. However, the material type was found to systematically affect the mechanical properties of AM porous biomaterials in general and the post-elastic/post-yield range (plateau stress and energy absorption capacity) in particular. To put this in perspective, topological design could cause up to 10-fold difference in the mechanical properties of AM porous biomaterials while up to 2-fold difference was observed as a consequence of changing the material type. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Effects of hot rolling and titanium content on the microstructure and mechanical properties of high boron Fe–B alloys

    International Nuclear Information System (INIS)

    He, Lin; Liu, Ying; Li, Jun; Li, Binghong

    2012-01-01

    Highlights: ► The content of B is 1.8 wt.% in the high boron Fe–B alloys. ► Hot-rolling improves the mechanical properties, especially the elongation. ► The Ti content affects the microstructure and mechanical properties. ► Eutectic boride can be eliminated when the atomic ratio of Ti/B is no less than 0.5. ► Alloy exhibits balanced mechanical properties when the atomic ratio of Ti/B is 0.5. -- Abstract: High boron Fe–B alloys (1.8 wt.% B) with different titanium contents are fabricated by Vacuum Induction Melting (VIM) technique. The integrated mechanical properties of the as-cast alloys are poor, especially the ductility. In this investigation, hot-rolling technology is used to improve the microstructure and mechanical properties. The microstructure analysis shows that hot rolling can reduce the size and improve the distribution of the reinforcements. The mechanical properties testing indicates that the yield strength is unchanged basically, but the tensile strength and elongation are improved greatly by hot rolling, especially the elongation. The content of titanium also has great effects on the microstructures and mechanical properties of the hot-rolled alloys. For the hot-rolled alloys, with the titanium content increasing, the ultimate tensile strength and yield strength first decrease slightly and then increase. The elongation and impact toughness are improved significantly. In particular, when the atomic ratio of Ti to B is 0.5, the reinforcements are almost entirely TiB 2 and uniformly distributed in the Fe-matrix. The ternary Fe–B–Ti alloy exhibits balanced mechanical properties: yield strength, ultimate tensile strength, elongation and impact toughness are 334 MPa, 602 MPa, 16.2% and 213 kJ/m 2 , respectively.

  9. Effect of Discontinuous Ultrasonic Treatment on Mechanical Properties and Microstructure of Cast Al413-SiCnp Nanocomposites

    Directory of Open Access Journals (Sweden)

    M.R. Dehnavi

    2015-05-01

    Full Text Available Effects of discontinuous ultrasonic treatment on the microstructure, nanoparticle distribution, and mechanical properties of cast Al413-SiCnp nanocomposites were studied. The results showed that discontinuous ultrasonic treatment was more effective in improving the mechanical properties of the cast nanocomposites than the equally timed continuous treatment. The yield and ultimate tensile strengths of Al413-2%SiCnp nanocomposites discontinuously treated for two 20 minute periods increased by about 126% and 100% compared to those of the monolithic sample, respectively. These improvements were about 107% and 94% for the nanocomposites continuously treated for a single 40 minute period. The improvement in the mechanical properties was associated with severe refinement of the microstructure, removal of the remaining gas layers on the particles surfaces, more effective fragmentation of the remaining agglomerates as well as improved wettability and distribution of the reinforcing particles during the first stage of solidification.

  10. EFFECT OF INTERMETALLIC PHASES ON CORROSION BEHAVIOR AND MECHANICAL PROPERTIES OF DUPLEX STAINLESS STEEL AND SUPER-DUPLEX STAINLESS STEEL

    Directory of Open Access Journals (Sweden)

    Prabhu Paulraj

    2015-08-01

    Full Text Available Duplex Stainless Steels (DSS and Super Duplex Stainless Steel (SDSS have excellent integration of mechanical and corrosion properties. However, the formation of intermetallic phases is a major problem in their usage. The mechanical and corrosion properties are deteriorated due to the presence of intermetallic phases. These phases are induced during welding, prolonged exposure to high temperatures, and improper heat treatments. The main emphasis of this review article is on intermetallic phases and their effects on corrosion and mechanical properties. First the effect of various alloying elements on DSS and SDSS has been discussed followed by formation of various intermetallic phases. The intermetallic phases affect impact toughness and corrosion resistance significantly. Their deleterious effect on weldments has also been reviewed.

  11. Effect of postdrawing temperature on structure, morphology and mechanical properties of melt-spun isotactic polypropylene tapes

    NARCIS (Netherlands)

    Loos, J.; Schimanski, T.

    2005-01-01

    Structure, morphology, and mechanical properties of melt-spun and postdrawn isotactic polypropylene (iPP) tapes are analyzed to study the effect of postdraw temperature applied. For affine drawing conditions, i.e., no effective relaxation of the molecules occurs during postdrawing, the Young's

  12. On the ways of improving mechanical properties of boiler steels subject to hydrogen effect

    International Nuclear Information System (INIS)

    Tkachev, V.I.; Litvin, A.K.; Zvezdin, Yu.I.

    1975-01-01

    The effect of oxygen on the strength properties of boiler steels Kh15M2 and 48TS subjected to heat treatment and preliminary plastic deformation has been studied. It is shown that changes in the strength properties of the steel are determined by the heterogeneity of its structure. Treatment which contributes to homogenization of the metal structure increases the resistance of the steel to detrimental effect of hydrogen. Absorption of hydrogen during cathode polarization at various current densities is shown

  13. Comparative Effect of Mo and Cr on Microstructure and Mechanical Properties in NbV-Microalloyed Bainitic Steels

    Directory of Open Access Journals (Sweden)

    Andrii Kostryzhev

    2018-02-01

    Full Text Available Steel product markets require the rolled stock with further increasing mechanical properties and simultaneously decreasing price. The steel cost can be reduced via decreasing the microalloying elements contents, although this decrease may undermine the mechanical properties. Multi-element microalloying with minor additions is the route to optimise steel composition and keep the properties high. However, this requires deep understanding of mutual effects of elements on each other’s performance with respect to the development of microstructure and mechanical properties. This knowledge is insufficient at the moment. In the present work we investigate the microstructure and mechanical properties of bainitic steels microalloyed with Cr, Mo, Nb and V. Comparison of 0.2 wt. % Mo and Cr additions has shown a more pronounced effect of Mo on precipitation than on phase balance. Superior strength of the MoNbV-steel originated from the strong solid solution strengthening effect. Superior ductility of the CrNbV-steel corresponded to the more pronounced precipitation in this steel. Nature of these mechanisms is discussed.

  14. Effect Of Coupling Agent On Microstructure And Mechanical Properties Of Polipropene-Flour Maizena Composite

    International Nuclear Information System (INIS)

    Sudirman; Karo Karo, Aloma; Darwinto, Tri; Teguh, Yulius S.P.P.; Handayani, Ari; Iraman, Dian

    2001-01-01

    Synthesize of PoIipropilene-flour maizena composite with addition of coupling agent have been done. Polypropylene (PP') which containing of CH 3 functional group was choosen due to its good property of degradable compare to Polyethylene (PE). The experiment carried out by mixing thermoplastic polymer (polypropylene with variation of PP MF2 and PP MFIO) with natural polymer ,flour maizena) varied in the mixing temperature of 180 c . The mixing caused the decreased mechanical properties of the PI' as major component. In addition, PE has better Mechanical properties than PP. Therefore, coupling agent of 3-Aminoprophyl triethoxy silane was added into the composite having function to homogenize the composite, thus the mechanical properties of the composite could increased. The experimental result showed that by adding the coupling agent of 10 phr (per hundred polypmpilene) ioto the PP-Maizena composite (60:40) . of the PP MFIO type could increased a tensile strength from 150.11kg/cm 2 to 226.93 kg/cm 2 , but it decreased the elongation at break from 75.7% to be brittle. Oil the contrary. the addition of coupling agent of 10 phr into PP MF2 could decreased either the tensile strength from 172.05 kg/cm2 to 154.93 kg/cm 2 , or the elongation at break of the composite from 520 % to 425 %

  15. Effect of strain rate on the mechanical properties of magnesium alloy AMX602

    Energy Technology Data Exchange (ETDEWEB)

    Shen, J. [Department of Mechanical Engineering, University of North Carolina at Charlotte, Charlotte, NC 28223-0001 (United States); Kondoh, K. [Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaragi, Osaka 567-0047 (Japan); Jones, T.L. [WMRD, US Army Research Laboratory, 4600 Deer Creek Loop, MD 21005-5069 (United States); Mathaudhu, S.N. [Department of Mechanical Engineering, University of California Riverside, Riverside, CA 92521 (United States); Kecskes, L.J. [WMRD, US Army Research Laboratory, 4600 Deer Creek Loop, MD 21005-5069 (United States); Wei, Q., E-mail: qwei@uncc.edu [Department of Mechanical Engineering, University of North Carolina at Charlotte, Charlotte, NC 28223-0001 (United States)

    2016-01-01

    In the present work, the effect of strain rate on the mechanical properties, particularly the plastic deformation behavior of a magnesium alloy, AMX602 (Mg–6%Al–0.5%Mn–2%Ca; all wt%), fabricated by powder metallurgy, has been investigated under both quasi-static (strain rate 1×10{sup −3} s{sup −1}) and dynamic (strain rate 4×10{sup 3} s{sup −1}) compressive loading. The alloyed powder was extruded at three different temperatures. The microstructure of the alloy was examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found that AMX602 exhibits an impressive mechanical behavior but with a slight anisotropy along different directions in both strength and compressive ductility (or malleability). The strength was found to be nearly independent of the extrusion temperature, particularly, under dynamic loading. Nanoindentation strain rate jump test reveals a strain rate sensitivity of ~0.018 to ~0.015, depending on the extrusion temperature. Sub-micrometer-scale particles of the intermetallic compound Al{sub 2}Ca were found with sizes ranging from ~100 nm to ~1.0 μm. These intermetallic particles are believed to have precipitated out during the extrusion process. They contribute to the formation of the ultrafine equiaxed grains which, in turn, help to improve the strength of the alloy by acting as barriers to dislocation motion. Adiabatic shear bands (ASBs) were observed in the dynamically loaded samples, the propagation of which eventually leads to final fracture of the specimens.

  16. Matrix density effects on the mechanical properties of SiC fiber-reinforced silicon nitride matrix properties

    Science.gov (United States)

    Bhatt, Ramakrishna T.; Kiser, Lames D.

    1990-01-01

    The room temperature mechanical properties were measured for SiC fiber reinforced reaction-bonded silicon nitride composites (SiC/RBSN) of different densities. The composites consisted of approx. 30 vol percent uniaxially aligned 142 micron diameter SiC fibers (Textron SCS-6) in a reaction-bonded Si3N4 matrix. The composite density was varied by changing the consolidation pressure during RBSN processing and by hot isostatically pressing the SiC/RBSN composites. Results indicate that as the consolidation pressure was increased from 27 to 138 MPa, the average pore size of the nitrided composites decreased from 0.04 to 0.02 microns and the composite density increased from 2.07 to 2.45 gm/cc. Nonetheless, these improvements resulted in only small increases in the first matrix cracking stress, primary elastic modulus, and ultimate tensile strength values of the composites. In contrast, HIP consolidation of SiC/RBSN resulted in a fully dense material whose first matrix cracking stress and elastic modulus were approx. 15 and 50 percent higher, respectively, and ultimate tensile strength values were approx. 40 percent lower than those for unHIPed SiC/RBSN composites. The modulus behavior for all specimens can be explained by simple rule-of-mixture theory. Also, the loss in ultimate strength for the HIPed composites appears to be related to a degradation in fiber strength at the HIP temperature. However, the density effect on matrix fracture strength was much less than would be expected based on typical monolithic Si3N4 behavior, suggesting that composite theory is indeed operating. Possible practical implications of these observations are discussed.

  17. Effect of vacuum impregnation temperature on the mechanical properties and osmotic dehydration parameters of apples

    Directory of Open Access Journals (Sweden)

    Sabrina Silva Paes

    2008-08-01

    Full Text Available The effect of sucrose solution temperature on the mechanical properties, water loss (WL, solids gain (SG and weight reduction (WR of apples (Fuji var. treated by vacuum impregnation was studied. Temperatures were varied from 10 to 50 ºC, using a sucrose solution of 50 ºBrix. The mechanical properties were studied throughout a stress relaxation test. The results showed that the SG varied between 10.57 and 14.29 % and the WL varied between 10.55 and 14.48 %. The treated fruit soluble solids increased with the temperature probably due to the lower viscosity of the solution. The maximum stress was highest at 10 ºC, decreasing at higher temperatures, probably due the softening of the structure.A impregnação a vácuo (VI de alimentos é realizada pela aplicação de vácuo em um tanque contendo o produto imerso em uma solução, seguida da recuperação da pressão atmosférica. Neste trabalho, estudou-se o efeito da temperatura da solução de sacarose nas propriedades mecânicas das amostras e na perda de água (WL, ganho de sólidos (SG e redução de peso (WR. A faixa de temperaturas estudada foi de 10 a 50 ºC, usando uma solução de sacarose com 50 ºBrix. As propriedades mecânicas das amostras foram estudadas através de ensaios mecânicos de deformação-relaxação. O SG variou entre 10.57 e 14.29 %, enquanto WL variou entre 10.55 e 14.48 %. O teor de sólidos das frutas tratadas aumentou com a temperatura, provavelmente devido à diminuição da viscosidade da solução. A tensão máxima foi maior a 10 ºC, diminuindo com a temperatura, devido ao amolecimento da estrutura.

  18. Effect of polyamines on mechanical and structural properties of Bombyx mori silk.

    Science.gov (United States)

    Yerra, Aparna; Mysarla, Danti Kumari; Siripurapu, Prasanthi; Jha, Anjali; Valluri, Satyavathi V; Mamillapalli, Anitha

    2017-01-01

    Silkworm, Bombyx mori (B. mori) belongs to the Lepidoptera family. The silk produced from this insect, mulberry silk, gained lot of importance as a fabric. Silk is being exploited as a biomaterial due to its surprising strength and biocompatibility. Polyamines (PA) are important cell growth regulators. In the present work the effect of treatment of polyamines, putrescine (Put), spermidine (Spd), and spermine (Spm) on the quantity and quality of silk produced was assessed. Results showed that exogenous feeding of Spd at a concentration of 50 µM increased fiber length significantly. Analysis by Fourier transform infrared (FTIR) on the properties of silk obtained from Spd treated silkworms revealed an increase in percentage of absorption with no difference in peak positions of amide I and amide III groups. Scanning electron microscopy (SEM) revealed an increase in diameter of silk. Further, analysis at molecular level showed an increase in fibroin expression in Spd treated silk glands. However, the Spd treatment showed no significant difference with respect to fibroin to sericin ratio per unit weight of cocoon, silk tenacity, and percent elongation. Thus, the present results show that polyamine treatment would influence silk quality at structural, mechanical, and molecular level in the Bombyx mori, which can be exploited in silk biomaterial production. © 2016 Wiley Periodicals, Inc.

  19. The effect of processing on the mechanical properties of self-reinforced composites

    Science.gov (United States)

    Hassani, Farzaneh; Martin, Peter J.; Falzon, Brian G.

    2018-05-01

    Hot-compaction is one of the most common manufacturing methods for creating recyclable all thermoplastic composites. The current work investigates the compaction of highly oriented self-reinforced fabrics with three processing methods to study the effect of pressure and temperature in the tensile mechanical properties of the consolidated laminates. Hot-press, calender roller and vacuum bag technique were adopted to consolidate bi-component polypropylene woven fabrics in a range of pressures and compaction temperatures. Hot-pressed samples exhibited the highest quality of compaction. The modulus of the hot-pressed samples increased with compaction temperature initially due to the improved interlayer bonding and decreased after a maximum at 150°C because of partial melting of the reinforcement phase. The calender roller technique exhibited to have smaller processing temperature window as the pressure is only applied for a short time and the fabrics start to shrink with increasing the processing temperature. The need for constraining the fabrics through the process is therefore found to be paramount. The Vacuum bag results showed this technique to be the least efficient method because of the low compaction pressure. Microscopic images and void content measurement of the consolidated samples further validate the results from tensile testing.

  20. Effects of major histocompatibility complex class II knockout on mouse bone mechanical properties during development

    Science.gov (United States)

    Simske, Steven J.; Bateman, Ted A.; Smith, Erin E.; Ferguson, Virginia L.; Chapes, Stephen K.

    2002-01-01

    We investigated the effect of major histocompatibility complex class II (MHC II) knockout on the development of the mouse peripheral skeleton. These C2D mice had less skeletal development at 8, 12 and 16 weeks of age compared to wild-type C57BL/6J (B6) male mice. The C2D mice had decreased femur mechanical, geometric and compositional measurements compared to wild type mice at each of these ages. C2D femur stiffness (S), peak force in 3-pt bending (Pm), and mineral mass (Min-M) were 74%, 64% and 66%, respectively, of corresponding B6 values at 8 weeks of age. Similar differences were measured at 12 weeks (for which C2D femoral S, Pm and Min-M were 71%, 72% and 73%, respectively, of corresponding B6 values) and at 16 weeks (for which C2D femoral S, Pm and Min-M were 80%, 66% and 61%, respectively, of corresponding B6 values). MHC II knockout delays the development of adult bone properties and is accompanied by lower body mass compared to wild-type controls.

  1. Effect of Cold Forging on Microstructure and MechanicalProperties of Al/SiC Composites

    Science.gov (United States)

    Hanamantraygouda, M. B.; Shivakumar, B. P., Dr; Siddappa, P. N.; Sampathkumar, L.; Prashanth, L.

    2018-02-01

    The objective of this work was to investigate the effect of cold forging on mechanical properties and microstructural study of Al MMCs, at different wt% of SiC and forging cycle. The Al-SiC composite material was fabricated by stir casting method at different weight percentage of SiC such as 2.5, 5, 7.5 and 10%. Further, the deformation characteristics during open-die forging of Al-SiC composite at cold conditions was investigated. Cast and forged composite material was subjected to hardness test, tensile test and impact test. The grain size, microstructure behaviour was investigated using optical microscope. The results show that hardness and strength of Al-SiC composite increases and ductility decreases as compared to Al alloy in both as-cast and forged conditions. Optical microscope images showed that the distribution of SiC in Al matrix was more homogeneous in a forged composite as compared to cast one and reduction of porosity was found. Further, it showed that due to forging cycle the grain size was reduced by 30% to 35% from initial size.

  2. Effect of cooling rate on the microstructure and mechanical properties of Nb-microalloyed steels

    International Nuclear Information System (INIS)

    Shanmugam, S.; Ramisetti, N.K.; Misra, R.D.K.; Mannering, T.; Panda, D.; Jansto, S.

    2007-01-01

    We describe here the effect of cooling rate on the microstructure and mechanical properties of Nb-microalloyed steels that were processed as structural beams at three different cooling rates. Nb-microalloyed steels exhibited increase in yield strength with increase in cooling rate during processing. However, the increase in the yield strength was not accompanied by loss in toughness. The microstructure at conventional cooling rate, primarily consisted of polygonal ferrite-pearlite microconstituents, while at intermediate cooling rate besides polygonal ferrite and pearlite contained significant fraction of degenerated pearlite and lath-type ferrite. At higher cooling rate, predominantly, lath-type (acicular) or bainitic ferrite was obtained. The precipitation characteristics were similar at the three cooling rates investigated with precipitation occurring at grain boundaries, on dislocations, and in the ferrite matrix. The fine scale (∼8-12 nm) precipitates in the ferrite matrix were MC type of niobium carbides. The microstructural studies suggest that the increase in toughness of Nb-microalloyed steels with increase in cooling rate is related to the change in the microstructure from predominantly ferrite-pearlite to predominantly bainitic ferrite

  3. Effect of cooling rate on the microstructure and mechanical properties of Nb-microalloyed steels

    Energy Technology Data Exchange (ETDEWEB)

    Shanmugam, S. [Center for Structural and Functional Materials, University of Louisiana at Lafayette, Lafayette, LA 70504-4130 (United States); Ramisetti, N.K. [Department of Chemical Engineering, University of Louisiana at Lafayette, Lafayette, LA 70504-4130 (United States); Misra, R.D.K. [Center for Structural and Functional Materials, University of Louisiana at Lafayette, Lafayette, LA 70504-4130 (United States); Department of Chemical Engineering, University of Louisiana at Lafayette, Lafayette, LA 70504-4130 (United States)], E-mail: dmisra@louisiana.edu; Mannering, T. [Nucor-Yamato Steel, P.O. Box 1228, 5929 East State Highway 18, Blytheville, AR 72316 (United States); Panda, D. [Nucor-Yamato Steel, P.O. Box 1228, 5929 East State Highway 18, Blytheville, AR 72316 (United States); Jansto, S. [Reference Metals, 1000 Old Pond Road, Bridgeville, PA 15017 (United States)

    2007-07-15

    We describe here the effect of cooling rate on the microstructure and mechanical properties of Nb-microalloyed steels that were processed as structural beams at three different cooling rates. Nb-microalloyed steels exhibited increase in yield strength with increase in cooling rate during processing. However, the increase in the yield strength was not accompanied by loss in toughness. The microstructure at conventional cooling rate, primarily consisted of polygonal ferrite-pearlite microconstituents, while at intermediate cooling rate besides polygonal ferrite and pearlite contained significant fraction of degenerated pearlite and lath-type ferrite. At higher cooling rate, predominantly, lath-type (acicular) or bainitic ferrite was obtained. The precipitation characteristics were similar at the three cooling rates investigated with precipitation occurring at grain boundaries, on dislocations, and in the ferrite matrix. The fine scale ({approx}8-12 nm) precipitates in the ferrite matrix were MC type of niobium carbides. The microstructural studies suggest that the increase in toughness of Nb-microalloyed steels with increase in cooling rate is related to the change in the microstructure from predominantly ferrite-pearlite to predominantly bainitic ferrite.

  4. Effect of pressing temperature on the mechanical properties of waste styrofoam filled sawdust composite

    Science.gov (United States)

    Nasution, H.; Harahap, H.; Riani, R.; Pelawi, A. I.

    2018-02-01

    This study has investigated the effect of pressing temperature on mechanical properties of waste styrofoam composite filled with sawdust. The waste styrofoam as the matrix was mixed with sawdust as filler and maleic anhydride (6%wt) as a compatibilizer. The weight fraction ratio between matrix and filler 70:30 (wt) and wood fiber size of 100 mesh were conducted. The pressing temperatures were investigated using a hot press with temperatures varied viz. 120, 130, 150, and 170 °C. Surface modification was applied to sawdust to diminish its polarity so that it could be compatible with the non-polar waste styrofoam matrix. Composites were evaluated using Instron and impact tester machine to investigate the tensile strength and impact strength of the material, respectively. The result indicated that tensile strength has decreased with the increase of pressing temperature where the largest tensile strength is at 130 °C of 33 MPa. The same trend has occurred on impact strength, where the value has reached of 300 J/cm2 on pressing temperature of 130 °C. From scanning electron microscopy (SEM) analysis it is also confirmed that during impact test, the resistance of the composite which has been pressed at the temperature of 130 °C have given better morphology than the composite at 170 °C.

  5. Effect of Fungal Deterioration on Physical and Mechanical Properties of Hemp and Flax Natural Fiber Composites

    Directory of Open Access Journals (Sweden)

    Bryn Crawford

    2017-10-01

    Full Text Available The development and application of bio-sourced composites have been gaining wide attention, yet their deterioration due to the growth of ubiquitous microorganisms during storage/manufacturing/in-service phases is still not fully understood for optimum material selection and design purposes. In this study, samples of non-woven flax fibers, hemp fibers, and mats made of co-mingled randomly-oriented flax or hemp fiber (50% and polypropylene fiber (50% were subjected to 28 days of exposure to (i no water-no fungi, (ii water only and (iii water along with the Chaetomium globosum fungus. Biocomposite samples were measured for weight loss over time, to observe the rate of fungal growth and the respiration of cellulose components in the fibers. Tensile testing was conducted to measure mechanical properties of the composite samples under different configurations. Scanning electron microscopy was employed to visualize fungal hyphal growth on the natural fibers, as well as to observe the fracture planes and failure modes of the biocomposite samples. Results showed that fungal growth significantly affects the dry mass as well as the tensile elastic modulus of the tested natural fiber mats and composites, and the effect depends on both the type and the length scale of fibers, as well as the exposure condition and time.

  6. Synergistic alloying effect on microstructural evolution and mechanical properties of Cu precipitation-strengthened ferritic alloys

    International Nuclear Information System (INIS)

    Wen, Y.R.; Li, Y.P.; Hirata, A.; Zhang, Y.; Fujita, T.; Furuhara, T.; Liu, C.T.; Chiba, A.; Chen, M.W.

    2013-01-01

    We report the influence of alloying elements (Ni, Al and Mn) on the microstructural evolution of Cu-rich nanoprecipitates and the mechanical properties of Fe–Cu-based ferritic alloys. It was found that individual additions of Ni and Al do not give rise to an obvious strengthening effect, compared with the binary Fe–Cu parent alloy, although Ni segregates at the precipitate/matrix interface and Al partitions into Cu-rich precipitates. In contrast, the co-addition of Ni and Al results in the formation of core–shell nanoprecipitates with a Cu-rich core and a B2 Ni–Al shell, leading to a dramatic improvement in strength. The coarsening rate of the core–shell precipitates is about two orders of magnitude lower than that of monolithic Cu-rich precipitates in the binary and ternary Fe–Cu alloys. Reinforcement of the B2 Ni–Al shells by Mn partitioning further improves the strength of the precipitation-strengthened alloys by forming ultrastable and high number density core–shell nanoprecipitates

  7. Effect of γ-irradiation on the physical and mechanical properties of chitosan powder

    International Nuclear Information System (INIS)

    Zainol, Ismail; Akil, Hazizan Md; Mastor, Azreena

    2009-01-01

    In this study, locally produced chitosan powder was irradiated with pre-determined doses of γ-ray (Co-60) of 10 kGy, 25 kGy, 50 kGy and 100 kGy respectively. The properties of both chitosan powder and the chitosan film were examined and compared with unradiated chitosan. Physical characteristic of the irradiated powder and film was studied using stereo microscope. It was observed that the γ-ray induces a noticeable colour tone intensity change to the chitosan. Further investigation using Fourier Transformed Infrared Spectroscopy (FT-IR) analysis has confirmed that the chain scission reaction was occurred as a result of γ-ray exposure through the depolymerization mechanisms. Interestingly, the degree of deacetylation (DD) of chitosan measured using FT-IR showed a negligible effect due to the exposure of γ-ray radiation. Further investigation on the viscosity average molecular weight (M v ) showed a reduction of M v from 577 kD of pure chitosan to 458 kD, 242 kD, 159 kD and 106 kD for 10 kGy, 25 kGy, 50 kGy and 100 kGy of γ-radiated chitosan respectively. In addition, the tensile strength and elongation at break showed a similar decreasing trend with increasing dosage of γ-ray

  8. Effect of carboxylic acids as compatibilizer agent on mechanical properties of thermoplastic starch and polypropylene blends.

    Science.gov (United States)

    Martins, Andréa Bercini; Santana, Ruth Marlene Campomanes

    2016-01-01

    In this work, polypropylene/thermoplastic starch (PP/TPS) blends were prepared as an alternative material to use in disposable packaging, reducing the negative polymeric environmental impact. Unfortunately, this material displays morphological characteristics typical of immiscible polymer blends and a compatibilizer agent is needed. Three different carboxyl acids: myristic (C14), palmitic (C16) and stearic acids (C18) were used as natural compatibilizer agent (NCA). The effects of NCA on the mechanical, physical, thermal and morphological properties of PP/TPS blends were investigated and compared against PP/TPS with and without PP-grafted maleic anhydride (PPgMA). When compared to PP/TPS, blends with C18, PPgMA and C14 presented an improvement of 25, 22 and 17% in tensile strength at break and of 180, 194 and 259% in elongation at break, respectively. The highest increase, 54%, in the impact strength was achieved with C14 incorporation. Improvements could be seen, through scanning electron microscopy (SEM) images, in the compatibility between the immiscible components by acids incorporation. These results showed that carboxylic acids, specifically C14, could be used as compatibilizer agent and could substitute PPgMA. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Effect of revert addition on microstructure and mechanical properties of M951 Ni-base superalloy

    International Nuclear Information System (INIS)

    Yang, Y.H.; Yu, J.J.; Sun, X.F.; Jin, T.; Guan, H.R.; Hu, Z.Q.

    2012-01-01

    Highlights: ► The microstructure is not influenced by the additions of recycled alloy. ► The stress rupture life significantly decreases with addition of recycled alloy. ► The stress rupture life is remarkably dependent on various revert additions. ► The stress rupture life has been significantly improved after filtration. ► The melt filtered through 20 ppi shows the lowest stress rupture life. - Abstract: The effect of recycled alloy proportion on the composition, microstructure and mechanical properties of M951 alloy has been investigated. With the addition of the recycled alloy proportion, the concentrations of boron and carbon obviously decrease. The microstructure is not influenced by the additions of recycled alloy. The stress rupture life significantly decreases with the addition of recycled alloy proportion. Because of the removal of oxide inclusions by filtration, the stress rupture life has been significantly improved, and it also shows a clear dependence upon passage size of the filter. The melt filtered through passage size of 20 ppi shows the lowest stress rupture life.

  10. Effect of vibration on microstructures and mechanical properties of 304 stainless steel GTA welds

    Science.gov (United States)

    Hsieh, Chih-Chun; Lai, Chien-Hong; Wu, Weite

    2013-07-01

    This study investigates the microstructures and mechanical properties of 304 stainless steel at various vibration frequencies during simultaneous vibration welding. The experimental results demonstrated that simultaneous vibration welding could accelerate the nucleation and grain refinement of the microstructures. The effect of the grain refinement was more evident at the resonant frequency (375 Hz) and a minimum content of residual δ-ferrite (4.0%). The γ phase grew in the preferential orientation of the (111) direction with and without vibration. The full width at half maximum of the diffraction peak widened after the vibration, which was attributed to the grain refinement. The residual stress could be efficiently removed through simultaneous vibration welding when the amplitude of the vibration was increased. Furthermore, the lowest residual stress (139 MPa) was found when the vibration frequency was 375 Hz. The hardness and Young's modulus exhibited slight increases with low and medium frequencies. The hardness values were increased by 7.6% and Young's modulus was increased by 15% when the vibration frequency was resonant (375 Hz).

  11. Effects of Bamboo Shoot Dietary Fiber on Mechanical Properties, Moisture Distribution, and Microstructure of Frozen Dough

    Directory of Open Access Journals (Sweden)

    Hua Zhang

    2017-01-01

    Full Text Available In this paper, the effects of Bamboo shoot dietary fiber (BSDF on the mechanical properties, moisture distribution, and microstructure of frozen dough were investigated. The state and distribution of water in frozen dough was determined by differential scanning calorimetry (DSC and low-field nuclear magnetic resonance (LNMR spectroscopy. The microstructure of frozen dough was studied. The structure of the gluten protein network found in wheat flour dough was studied by scanning electron microscopy (SEM. The result showed that the BSDF could significantly improve the viscoelasticity and extensibility of frozen dough after thawing in a dose-dependent manner. It was significantly improved with the increase in the addition amount of BSDF (P<0.05. DSC analysis showed that the freezable water content and thermal stability of frozen dough were increased after the addition of BSDF. LNMR analysis showed that the appropriate (<0.1% addition amount of BSDF could significantly (P<0.05 decline the contents of bound water. Meanwhile, the loose bound water and free water were raised significantly (P<0.05 after the addition of BSDF. Moreover, the addition of BSDF induces arrangement of starch granule and gluten network in frozen dough. BSDF can be used as a novel quality improver of frozen dough.

  12. Effect of vacuum and temperature on the mechanical properties of an aramid/epoxy composite

    International Nuclear Information System (INIS)

    Hahn, H.T.; Chin, W.K.

    1981-01-01

    The mechanical properties of a Kevlar 49/epoxy composite intended for flywheel applications are investigated in the laboratory and simulated service environments. The filament-wound composites were preconditioned in the test environment for 1-5 months, during which weight change was monitored, then subjected to tensile and fatigue tests at room temperature or 75 deg in vacuum. A weight loss of only 1.63% is observed after 11 months in the simulated service environment, most of which is attributed to moisture desorbed in vacuum. In contrast to air at 75 C, the simulated service environment is also found to produce no deleterious effects on static and fatigue strengths, probably to moisture desorption and a lack of oxidation. A fatigue life of about 100,000 cycles for 95% survival proability is obtained at 70% of the average static strength, and the macroscopic failure mode, which results in a brush-like formation, is observed to be independent of the type of loading and preconditioning. It is concluded that an environment of 75 C in vacuum is no deterrent to the application of the composite in flywheels, however the possibility of increasing service temperature to 150 C should be investigated

  13. Effect of tempering on the microstructure and mechanical properties of a medium carbon bainitic steel

    Energy Technology Data Exchange (ETDEWEB)

    Kang, J. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Zhang, F.C., E-mail: zfc@ysu.edu.cn [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); National Engineering Research Center for Equipment and Technology of Cold Strip Rolling, Yanshan University, Qinhuangdao 066004 (China); Yang, X.W. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Lv, B. [College of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao 066004 (China); Wu, K.M. [International Research Institute for Steel Technology, Wuhan University of Science and Technology, Wuhan 430081 (China); Materials Science and Metallurgy, University of Cambridge, Cambridge CB2 3QZ (United Kingdom)

    2017-02-16

    The effect of tempering on the microstructure and mechanical properties of a medium carbon bainitic steel has been investigated through optical microscopy, electron back-scattered diffraction, transmission electron microscopy and X-ray diffraction analyses. A nano-level microstructure containing plate-like bainitic ferrite and film-like retained austenite is obtained by isothermal transformation at Ms+10 °C followed by tempering within 240–450 °C. Results show that the sample tempered at 340 °C occupies the optimal balance of strength and toughness by maintaining a certain level of plasticity; samples tempered at 320 °C and 360 °C with low and high yield ratio come second. The microstructure of the steel is not sensitive to tempering temperatures before 360 °C. When the temperature is increased to 450 °C, the significantly coarsened bainitic ferrite plate and the occurrence of a small quantity of carbide precipitation account for its low toughness. The amount of retained austenite increases with the tempering temperature before 400 °C, followed by decreasing with further increase in the temperature. This behavior is related to the competition between retained austenite further transforming into bainite and decomposing into carbide during tempering.

  14. Effects of multi-pass arc welding on mechanical properties of carbon steel C25 plate

    International Nuclear Information System (INIS)

    Adedayo, S.M.; Babatunde, A.S.

    2013-01-01

    The effects of multi-pass welding on mechanical properties of C25 carbon steel plate were examined. Mild steel plate workpieces of 90 x 55 mm 2 area and 10 mm thickness with a 30 degrees vee weld-grooves were subjected to single and multi-pass welding. Toughness, hardness and tensile tests of single and multi-pass welds were conducted. Toughness values of the welds under double pass welds were higher than both single pass and unwelded alloy, at respective maximum values of 2464, 2342 and 2170 kN/m. Hardness values were reduced under double pass relative to single pass welding with both being lower than the value for unwelded alloy; the values were 40.5, 43.2 and 48.5 Rs respectively at 12 mm from the weld line. The tensile strength of 347 N/mm 2 under multi-pass weld was higher than single pass weld with value of 314 N/mm 2 . Therefore, the temperature distribution and apparent pre-heating during multi-pass welding increased the toughness and tensile strength of the weldments, but reduced the hardness. (au)

  15. Investigate The Effect Of Welding Parameters On Mechanical Properties During The Welding Of Al-6061 Alloy

    Directory of Open Access Journals (Sweden)

    Rajendra Prasad

    2017-10-01

    Full Text Available Friction welding is a solid state welding technique which is being used in recent times to weld similar as well as dissimilar metals for getting defect free weld. Many combinations like low carbon to stainless steel austenitic to ferrite stainless steel aluminium to copper and titanium to aluminium or steel have been tried out by various solid state welding processes with quite good results. In the present work the 3 level full factorial design has been employed to investigate the effect of welding parameters on tensile strength toughness and heat generation during the welding of Al-6061 alloy. Mathematical relationships between friction welding parameters and mechanical properties like heat generation tensile strength and toughness have also been developed. An attempt has also been made to examine the fracture surfaces of test specimens using SEM. It has been found that welding speed is the most significant parameter thats affect the heat generation tensile strength and toughness. it has been found that tensile strength and toughness during welding increases with increased in welding speed while tensile strength and toughness initially increased as the welding time increases after that it decreased with increase in welding time. The difference in weight of alloying elements can be clearly seen by analyzing spectrum of elements.

  16. Effect of the build orientation on the mechanical properties and fracture modes of SLM Ti–6Al–4V

    Energy Technology Data Exchange (ETDEWEB)

    Simonelli, M., E-mail: M.Simonelli@lboro.ac.uk [Department of Materials, Loughborough University, Loughborough LE11 3TU (United Kingdom); Tse, Y.Y. [Department of Materials, Loughborough University, Loughborough LE11 3TU (United Kingdom); Tuck, C. [Additive Manufacturing and 3D Printing Research Group, Faculty of Engineering, The University of Nottingham, Nottingham NG7 2RD (United Kingdom)

    2014-10-20

    Recent research on the additive manufacturing (AM) of Ti alloys has shown that the mechanical properties of the parts are affected by the characteristic microstructure that originates from the AM process. To understand the effect of the microstructure on the tensile properties, selective laser melted (SLM) Ti–6Al–4V samples built in three different orientations were tensile tested. The investigated samples were near fully dense, in two distinct conditions, as-built and stress relieved. It was found that the build orientation affects the tensile properties, and in particular the ductility of the samples. The mechanical anisotropy of the parts was discussed in relation to the crystallographic texture, phase composition and the predominant fracture mechanisms. Fractography and electron backscatter diffraction (EBSD) results indicate that the predominant fracture mechanism is intergranular fracture present along the grain boundaries and thus provide and explain the typical fracture surface features observed in fracture AM Ti–6Al–4V.

  17. Effect of the build orientation on the mechanical properties and fracture modes of SLM Ti–6Al–4V

    International Nuclear Information System (INIS)

    Simonelli, M.; Tse, Y.Y.; Tuck, C.

    2014-01-01

    Recent research on the additive manufacturing (AM) of Ti alloys has shown that the mechanical properties of the parts are affected by the characteristic microstructure that originates from the AM process. To understand the effect of the microstructure on the tensile properties, selective laser melted (SLM) Ti–6Al–4V samples built in three different orientations were tensile tested. The investigated samples were near fully dense, in two distinct conditions, as-built and stress relieved. It was found that the build orientation affects the tensile properties, and in particular the ductility of the samples. The mechanical anisotropy of the parts was discussed in relation to the crystallographic texture, phase composition and the predominant fracture mechanisms. Fractography and electron backscatter diffraction (EBSD) results indicate that the predominant fracture mechanism is intergranular fracture present along the grain boundaries and thus provide and explain the typical fracture surface features observed in fracture AM Ti–6Al–4V

  18. Ab initio investigation of helium in Y_2Ti_2O_7: Mobility and effects on mechanical properties

    International Nuclear Information System (INIS)

    Danielson, T.; Tea, E.; Hin, C.

    2016-01-01

    Oxide nanoclusters (NCs) in nanostructured ferritic alloys (NFAs) are known to be efficient trapping sites for the transmutation product helium. In this study, the migration barriers and potential energy surfaces of helium in Y_2Ti_2O_7 are presented to explain the mobility of helium through oxide NCs and shed light on the accumulation of helium and the trapping mechanisms of the oxides. A complex tunnel-shaped potential energy surface is identified and gives rise to relatively large migration barriers. Subsequently, the effect of helium accumulation on the mechanical properties of Y_2Ti_2O_7 oxide nanoclusters is investigated and it is shown that the mechanical properties of the oxide do not significantly degrade as helium accumulates. - Highlights: • Migration barriers of helium in Y_2Ti_2O_7 are calculated using the climbing image nudged elastic band. • Helium Potential energy surfaces are calculated. • Mechanical properties of varying helium concentrations are presented.

  19. Effect of scandium additions on microstructure and mechanical properties of Al-Zn-Mg alloy welds

    International Nuclear Information System (INIS)

    Dev, Selvi; Stuart, A. Archibald; Kumaar, R.C. Ravi Dev; Murty, B.S.; Rao, K. Prasad

    2007-01-01

    The microstructure and mechanical properties of fusion zones of medium strength Al-Zn-Mg alloy (RDE-40) welds obtained by using different fillers containing various amount of scandium was investigated. It was observed that addition of scandium led to very significant grain refinement in the fusion zone especially for scandium levels greater than the eutectic composition (0.55 wt%). The grain refinement led to the reduction in solidification cracking and improved the tensile properties of fusion zone compared to the ones obtained by the commercial AA5556 filler

  20. High temperature treatment effect on physical and mechanical properties of titanium alloys

    International Nuclear Information System (INIS)

    Shinyaev, A.Ya.; Illarionov, Eh.I.

    2000-01-01

    The kinetics of variations in electric conductivity, hardness, strength and plastic properties is studied for Ti - 0.75 % W, Ti - 3.5 % W, Ti - 3.5 % W - 2.8 % Zr, Ti - 3.7 % W - 5.4 % Al, Ti - 6.4 % Al - 3.5 % W - 3 % Zr alloys on quench ageing at 400 - 700 Deg C. In the temperature dependences of electric conductivity and mechanical properties the extreme values are observed which may be interpreted as evidence of β-solid solution binodal decomposition [ru

  1. Effect of porosity, tissue density, and mechanical properties on radial sound speed in human cortical bone

    Energy Technology Data Exchange (ETDEWEB)

    Eneh, C. T. M., E-mail: chibuzor.eneh@uef.fi, E-mail: markus.malo@uef.fi, E-mail: janne.karjalainen@boneindex.fi, E-mail: jukka.liukkonen@gmail.com, E-mail: juha.toyras@uef.fi; Töyräs, J., E-mail: chibuzor.eneh@uef.fi, E-mail: markus.malo@uef.fi, E-mail: janne.karjalainen@boneindex.fi, E-mail: jukka.liukkonen@gmail.com, E-mail: juha.toyras@uef.fi; Jurvelin, J. S., E-mail: jukka.jurvelin@uef.fi [Department of Applied Physics, University of Eastern Finland, P.O. Box 1627, Kuopio FI-70211, Finland and Diagnostic Imaging Center, Kuopio University Hospital, P.O. Box 100, Kuopio FI-70029 (Finland); Malo, M. K. H., E-mail: chibuzor.eneh@uef.fi, E-mail: markus.malo@uef.fi, E-mail: janne.karjalainen@boneindex.fi, E-mail: jukka.liukkonen@gmail.com, E-mail: juha.toyras@uef.fi; Liukkonen, J., E-mail: chibuzor.eneh@uef.fi, E-mail: markus.malo@uef.fi, E-mail: janne.karjalainen@boneindex.fi, E-mail: jukka.liukkonen@gmail.com, E-mail: juha.toyras@uef.fi [Department of Applied Physics, University of Eastern Finland, P.O. Box 1627, Kuopio FI-70211 (Finland); Karjalainen, J. P., E-mail: chibuzor.eneh@uef.fi, E-mail: markus.malo@uef.fi, E-mail: janne.karjalainen@boneindex.fi, E-mail: jukka.liukkonen@gmail.com, E-mail: juha.toyras@uef.fi [Bone Index Finland Ltd., P.O. Box 1188, Kuopio FI-70211 (Finland)

    2016-05-15

    Purpose: The purpose of this study was to investigate the effect of simultaneous changes in cortical porosity, tissue mineral density, and elastic properties on radial speed of sound (SOS) in cortical bone. The authors applied quantitative pulse-echo (PE) ultrasound techniques that hold much potential especially for screening of osteoporosis at primary healthcare facilities. Currently, most PE measurements of cortical thickness, a well-known indicator of fracture risk, use a predefined estimate for SOS in bone to calculate thickness. Due to variation of cortical bone porosity, the use of a constant SOS value propagates to an unknown error in cortical thickness assessment by PE ultrasound. Methods: The authors conducted 2.25 and 5.00 MHz focused PE ultrasound time of flight measurements on femoral diaphyses of 18 cadavers in vitro. Cortical porosities of the samples were determined using microcomputed tomography and related to SOS in the samples. Additionally, the effect of cortical bone porosity and mechanical properties of the calcified matrix on SOS was investigated using numerical finite difference time domain simulations. Results: Both experimental measurements and simulations demonstrated significant negative correlation between radial SOS and cortical porosity (R{sup 2} ≥ 0.493, p < 0.01 and R{sup 2} ≥ 0.989, p < 0.01, respectively). When a constant SOS was assumed for cortical bone, the error due to variation of cortical bone porosity (4.9%–16.4%) was about 6% in the cortical thickness assessment in vitro. Conclusions: Use of a predefined, constant value for radial SOS in cortical bone, i.e., neglecting the effect of measured variation in cortical porosity, propagated to an error of 6% in cortical thickness. This error can be critical as characteristic cortical thinning of 1.10% ± 1.06% per yr decreases bending strength of the distal radius and results in increased fragility in postmenopausal women. Provided that the cortical porosity can be estimated

  2. Effect of porosity, tissue density, and mechanical properties on radial sound speed in human cortical bone

    International Nuclear Information System (INIS)

    Eneh, C. T. M.; Töyräs, J.; Jurvelin, J. S.; Malo, M. K. H.; Liukkonen, J.; Karjalainen, J. P.

    2016-01-01

    Purpose: The purpose of this study was to investigate the effect of simultaneous changes in cortical porosity, tissue mineral density, and elastic properties on radial speed of sound (SOS) in cortical bone. The authors applied quantitative pulse-echo (PE) ultrasound techniques that hold much potential especially for screening of osteoporosis at primary healthcare facilities. Currently, most PE measurements of cortical thickness, a well-known indicator of fracture risk, use a predefined estimate for SOS in bone to calculate thickness. Due to variation of cortical bone porosity, the use of a constant SOS value propagates to an unknown error in cortical thickness assessment by PE ultrasound. Methods: The authors conducted 2.25 and 5.00 MHz focused PE ultrasound time of flight measurements on femoral diaphyses of 18 cadavers in vitro. Cortical porosities of the samples were determined using microcomputed tomography and related to SOS in the samples. Additionally, the effect of cortical bone porosity and mechanical properties of the calcified matrix on SOS was investigated using numerical finite difference time domain simulations. Results: Both experimental measurements and simulations demonstrated significant negative correlation between radial SOS and cortical porosity (R"2 ≥ 0.493, p < 0.01 and R"2 ≥ 0.989, p < 0.01, respectively). When a constant SOS was assumed for cortical bone, the error due to variation of cortical bone porosity (4.9%–16.4%) was about 6% in the cortical thickness assessment in vitro. Conclusions: Use of a predefined, constant value for radial SOS in cortical bone, i.e., neglecting the effect of measured variation in cortical porosity, propagated to an error of 6% in cortical thickness. This error can be critical as characteristic cortical thinning of 1.10% ± 1.06% per yr decreases bending strength of the distal radius and results in increased fragility in postmenopausal women. Provided that the cortical porosity can be estimated in vivo

  3. Effect of aging on the tribological and mechanical properties of a high-nitrogen stainless austenitic steel

    International Nuclear Information System (INIS)

    Korshunov, L.G.; Chernenko, N.L.; Tereshchenko, N.A.; Uvarov, A.I.

    2005-01-01

    The effect of aging, associated with predominant precipitation of vanadium nitrides (VN), on tribological and mechanical properties of austenitic steel 10Kh18AG18N5MF hardened from 1100 Deg C is studied. Metallographic, X-ray diffraction and electron microscopical methods are used to study structural transformations proceeding in the steel on aging as well as on friction loading under conditions of dry slipping friction in steel-abrasive and steel-steel pairs. It is shown that the aging at temperatures of 600-700 Deg C resulting in a considerable increase of strength properties of the steel demonstrates a relatively weak positive effect on steel resistance to abrasive and adhesive wear. It is stated that the use of aging by continuous mechanism permits attaining favourable mechanical and tribological properties in vanadium-alloying nitrogen-bearing austenitic steels [ru

  4. Alpha prime effect on mechanical properties and corrosion resistance of UR 52N+ duplex stainless steel

    International Nuclear Information System (INIS)

    Fontes, Talita Filier

    2009-01-01

    Alpha prime phase leads to decreased corrosion resistance and mechanical properties losses of duplex stainless steels. In this work mechanical and electrochemical tests were performed in duplex stainless steel UR 52N+ aged at 475 degree C for various periods in order to determine the sensibility of these tests to alpha prime presence. Hardness tests showed a gradual increase in its values; on the other hand, impact tests revealed that the material aged for 12h losses about 80% of energy absorption capacity of the solution annealed sample. Notwithstanding cyclic polarization tests showed that significant changes are only noted for aging times greater than 96h. (author)

  5. Effect of tool pin profile on microstructure and mechanical properties of friction stir welded AZ31B magnesium alloy

    International Nuclear Information System (INIS)

    Motalleb-nejad, P.; Saeid, T.; Heidarzadeh, A.; Darzi, Kh.; Ashjari, M.

    2014-01-01

    Highlights: • FSW conditions for defect free joints of AZ31B magnesium alloy were reached. • The effect of FSW factors such pin design on the features of the welds was studied. • Taper pin caused to finest grains and highest mechanical properties. • The superior properties of the joints were achieved at the condition of ω 2 /υ = 6300. • All the tensile fractures occurred at the interface of the SZ and base metal. - Abstract: In this investigation the effect of friction stir welding pin geometry on the microstructure and mechanical properties of AZ31B magnesium alloy joints is studied. The considered pin geometries are simple cylindrical, screw threaded cylindrical and taper. The joints are friction stir welded at different traverse and rotational speeds. Microstructures of the joints are examined using the optical and scanning electron microscopes. Also, the tensile properties and hardness of the joints are measured. The results show that taper and screw threaded cylindrical pins produce defect free joints. In addition, the taper pin results in finest microstructure and highest mechanical properties. Furthermore, it is found that rotational speed has a more significant role on the final microstructure and mechanical properties of the joints, compared to the traverse speed

  6. The effect of point mutations on structure and mechanical properties of collagen-like fibril: A molecular dynamics study

    International Nuclear Information System (INIS)

    Marlowe, Ashley E.; Singh, Abhishek; Yingling, Yaroslava G.

    2012-01-01

    Understanding sequence dependent mechanical and structural properties of collagen fibrils is important for the development of artificial biomaterials for medical and nanotechnological applications. Moreover, point mutations are behind many collagen associated diseases, including Osteogenesis Imperfecta (OI). We conducted a combination of classical and steered atomistic molecular dynamics simulations to examine the effect of point mutations on structure and mechanical properties of short collagen fibrils which include mutations of glycine to alanine, aspartic acid, cysteine, and serine or mutations of hydroxyproline to arginine, asparagine, glutamine, and lysine. We found that all mutations disrupt structure and reduce strength of the collagen fibrils, which may affect the hierarchical packing of the fibrils. The glycine mutations were more detrimental to mechanical strength of the fibrils (WT > Ala > Ser > Cys > Asp) than that of hydroxyproline (WT > Arg > Gln > Asn > Lys). The clinical outcome for glycine mutations agrees well with the trend in reduction of fibril's tensile strength predicted by our simulations. Overall, our results suggest that the reduction in mechanical properties of collagen fibrils may be used to predict the clinical outcome of mutations. Highlights: ► All mutations disrupt structure and bonding pattern and reduce strength of the collagen fibrils. ► Gly based mutations are worst to mechanical integrity of fibrils than that of Hyp. ► Lys and Arg mutations most dramatically destabilize collagen fibril properties. ► Clinical outcome of mutations may be related to the reduced mechanical properties of fibrils.

  7. The effect of point mutations on structure and mechanical properties of collagen-like fibril: A molecular dynamics study

    Energy Technology Data Exchange (ETDEWEB)

    Marlowe, Ashley E.; Singh, Abhishek; Yingling, Yaroslava G., E-mail: yara_yingling@ncsu.edu

    2012-12-01

    Understanding sequence dependent mechanical and structural properties of collagen fibrils is important for the development of artificial biomaterials for medical and nanotechnological applications. Moreover, point mutations are behind many collagen associated diseases, including Osteogenesis Imperfecta (OI). We conducted a combination of classical and steered atomistic molecular dynamics simulations to examine the effect of point mutations on structure and mechanical properties of short collagen fibrils which include mutations of glycine to alanine, aspartic acid, cysteine, and serine or mutations of hydroxyproline to arginine, asparagine, glutamine, and lysine. We found that all mutations disrupt structure and reduce strength of the collagen fibrils, which may affect the hierarchical packing of the fibrils. The glycine mutations were more detrimental to mechanical strength of the fibrils (WT > Ala > Ser > Cys > Asp) than that of hydroxyproline (WT > Arg > Gln > Asn > Lys). The clinical outcome for glycine mutations agrees well with the trend in reduction of fibril's tensile strength predicted by our simulations. Overall, our results suggest that the reduction in mechanical properties of collagen fibrils may be used to predict the clinical outcome of mutations. Highlights: Black-Right-Pointing-Pointer All mutations disrupt structure and bonding pattern and reduce strength of the collagen fibrils. Black-Right-Pointing-Pointer Gly based mutations are worst to mechanical integrity of fibrils than that of Hyp. Black-Right-Pointing-Pointer Lys and Arg mutations most dramatically destabilize collagen fibril properties. Black-Right-Pointing-Pointer Clinical outcome of mutations may be related to the reduced mechanical properties of fibrils.

  8. Effect of fabrication processes on mechanical properties of glass fiber reinforced polymer composites for 49 meter (160 foot recreational yachts

    Directory of Open Access Journals (Sweden)

    Dave (Dae-Wook Kim

    2010-03-01

    Full Text Available Polymer composite materials offer high strength and stiffness to weight ratio, corrosion resistance, and total life cost reductions that appeal to the marine industry. The advantages of composite construction have led to their incorporation in U.S. yacht hull structures over 46 meters (150 feet in length. In order to construct even larger hull structures, higher quality composites with lower cost production techniques need to be developed. In this study, the effect of composite hull fabrication processes on mechanical properties of glass fiber reinforced plastic (GFRP composites is presented. Fabrication techniques investigated during this study are hand lay-up (HL, vacuum infusion (VI, and hybrid (HL + VI processes. Mechanical property testing includes: tensile, compressive, and ignition loss sample analysis. Results demonstrate that the vacuum pressure implemented during composite fabrication has an effect on mechanical properties. The VI processed GFRP yields improved mechanical properties in tension/compression strengths and tensile modulus. The hybrid GFRP composites, however, failed in a sequential manor, due to dissimilar failure modes in the HL and VI processed sides. Fractography analysis was conducted to validate the mechanical property testing results.

  9. Effect of fabrication processes on mechanical properties of glass fiber reinforced polymer composites for 49 meter (160 foot) recreational yachts

    Science.gov (United States)

    Kim, Dave (dea-wook); Hennigan, Daniel John; Beavers, Kevin Daniel

    2010-03-01

    Polymer composite materialsoffer high strength and stiffness to weight ratio, corrosion resistance, and total life cost reductions that appeal to the marine industry. The advantages of composite construction have led to their incorporation in U.S. yacht hull structures over 46 meters (150 feet) in length. In order to construct even larger hull structures, higher quality composites with a lower cost production techniques need to be developed. In this study, the effect of composite hull fabrication processes on mechanical properties of glass fiber reinforced plastic(GFRP) composites is presented. Fabrication techniques used in this study are hand lay-up (HL), vacuum infusion (VI), and hybrid (HL+VI) processes. Mechanical property testing includes: tensile, compressive, and ignition loss sample analysis. Results demonstrate that the vacuum pressure implemented during composite fabrication has an effect on mechanical properties. The VI processed GFRP yields improved mechanical properties in tension/compression strengths and tensile modulus. The hybrid GFRP composites, however, failed in a sequential manor, due to dissimilar failure modes in the HL and VI processed sides. Fractography analysis was conducted to validate the mechanical property testing results

  10. Effect of graphene orientation on microstructure and mechanical properties of silicon nitride ceramics

    Directory of Open Access Journals (Sweden)

    Yubing Zhang

    2018-03-01

    Full Text Available Mechanical properties and microstructure of graphene platelets reinforced Si3N4 composites have been investigated and compared to monolithic Si3N4. The microstructure shows that graphene platelets are parallel to each other and perpendicular to the hot pressing direction. Fracture toughness and flexural strength of composite with 1 wt.% graphene measured on polished surface perpendicular to hot pressing direction are 8.7 MPa·m1/2 and 892 MPa, respectively, which are increased about 14.5% and 20.2% compared with that parallel to hot pressing direction. The anisotropy of microstructure and mechanical properties of composites can be explained by the intrinsic anisotropy of graphene as well as the crack deflection energy release rate and the weak boundary bonding between graphene and Si3N4 caused by the thermal expansion mismatch.

  11. Effect of surface decarburization on the mechanical properties of high strength low alloy steel

    International Nuclear Information System (INIS)

    Saqib, S.

    1993-01-01

    An attempt has been made to study the relationship of mechanical properties with the microstructure of a high strength low alloy steel. A thorough investigation was conducted on the steel sheet and variation in mechanical properties was observed across its thickness with a change in the microstructure. Change in hardness and tensile strength at the surface compare to the core of the material is attributed to decarburization. The current research indicates that the correlation between hardness and tensile strength is not valid for steels if the hardness is determined on the surface only. Great care should be taken at the time of determination of tensile strength by using conversion charts/tables on the basis of hardness values obtained by practical means. (author)

  12. Effect of heat treatments on precipitate microstructure and mechanical properties of CuCrZr alloy

    DEFF Research Database (Denmark)

    Singh, B.N; Edwards, D.J.; Tähtinen, S.

    2004-01-01

    A number of specimens of CuCrZr alloy was prime aged and then overaged at 600oC for 1, 2 and 4 hours and for 4 hours at 700 and 850oC. After different heat treatments, both the precipitate microstructure and mechanical properties were characterized.Mechanical properties were determined at 50...... and 300oC. Some selected specimens in the prime aged as well as overaged conditions were irradiated in the BR-2 reactor at Mol at 60 and 300oC to a displacement dose level of ~0.3 dpa. Irradiated specimens weremechanically tested at 60 and 300oC. The post-deformation microstructure of the irradiated...

  13. The effects of glucocorticoid on microarchitecture, collagen, mineral and mechanical properties of sheep femur cortical bone

    DEFF Research Database (Denmark)

    Ding, Ming; Danielsen, Carl Christian; Overgaard, Søren

    2011-01-01

    of 3 months without treatment. Group 3 was left untreated and served as controls. All sheep received a restricted diet with low calcium and phosphorus. At sacrifice, cortical bone samples from the femur midshaft of each sheep were harvested, micro-CT scanned and subjected to three-point bending...... and tensile strength testing. Bone collagen and mineral were determined. Cortical porosity was significantly increased in the glucocorticoid-2 compared with the glucocorticoid-1 and control groups. Apparent density was significantly decreased in the glucocorticoid-2 compared with the glucocorticoid-1 group....... Collagen content was significantly increased in the glucocorticoid-2 compared with the glucocorticoid-1 and control groups. Bone mineral content did not differ between the groups. Neither the three-point bending mechanical properties nor the tensile mechanical properties differed significantly between...

  14. Effect of deformation and annealing on mechanical properties of nickel-rhenium alloys

    International Nuclear Information System (INIS)

    Mashkova, V.M.

    1978-01-01

    Studied have been the mechanical properties of nickel-rhenium alloys, depending on the extent of deformation and heat treatment leading to softening. The mechanical properties of the alloys have been estimated by the results of the tensile tests of wire samples. The softening of the alloy at different temperatures is judged about by the variation in hardness. The results of the study indicate that the most abrupt reduction in the hardness of the cold-hardened metal occurs at 900-1,000 deg C and the hold-time of 1 min. Increase in the hold-time at such temperature almost does not reduce the hardness. It is established that in order to soften nickel-rhenium alloys in the process of the cold-deformation at brief annealings in the air the hold-time should not exceed 5 min at 800-900 deg C

  15. Effect of initial microstructure on the microstructural evolution and mechanical properties of Ti during cold rolling

    International Nuclear Information System (INIS)

    Stolyarov, V.V.; Zhu, Y.T.; Raab, G.I.; Zharikov, A.I.; Valiev, R.Z.

    2004-01-01

    Ultrafine-grained (UFG) Ti rods were produced via cold rolling UFG and coarse-grained (CG) Ti stocks. The initial UFG stock was produced via equal channel angular pressing. It was found that the initial UFG structure had beneficial influence on the mechanical properties of the cold-rolled Ti rods. Compared with Ti rods with initial CG microstructure, the Ti rods with the initial UFG microstructure have both higher strength and higher ductility after being cold rolled to varying strains. Transmission electron microscopy revealed that the Ti rods with the initial UFG microstructure had finer, more homogeneous microstructures after cold rolling. This study demonstrates the merit of UFG Ti processed by ECAP for further shaping and forming into structural components with superior mechanical properties

  16. Effect of multiple forming tools on geometrical and mechanical properties in incremental sheet forming

    Science.gov (United States)

    Wernicke, S.; Dang, T.; Gies, S.; Tekkaya, A. E.

    2018-05-01

    The tendency to a higher variety of products requires economical manufacturing processes suitable for the production of prototypes and small batches. In the case of complex hollow-shaped parts, single point incremental forming (SPIF) represents a highly flexible process. The flexibility of this process comes along with a very long process time. To decrease the process time, a new incremental forming approach with multiple forming tools is investigated. The influence of two incremental forming tools on the resulting mechanical and geometrical component properties compared to SPIF is presented. Sheets made of EN AW-1050A were formed to frustums of a pyramid using different tool-path strategies. Furthermore, several variations of the tool-path strategy are analyzed. A time saving between 40% and 60% was observed depending on the tool-path and the radii of the forming tools while the mechanical properties remained unchanged. This knowledge can increase the cost efficiency of incremental forming processes.

  17. A comprehensive investigation into the effect of temperature variation on the mechanical properties of sustainable concrete

    OpenAIRE

    El Mir Abdulkader; Nehme Salem

    2017-01-01

    Minimizing the production energy and resources consumption are the key principle for engineering sustainability. In the case of concrete structures, this concept can be achieved by the use of materials in the most efficient way considering in the mix design the optimal mechanical and durability properties. The substitution of ordinary Portland cement for other supplementary cementitious materials is assessing the possibility of enhancing the sustainability and decreasing the environmental imp...

  18. Effect of ECAP on microstructure and mechanical properties of cast AZ91 magnesium alloy

    International Nuclear Information System (INIS)

    Chung, C W; Gao, W; Ding, R G; Chiu, Y L

    2010-01-01

    An as-cast AZ91 magnesium alloy was processed by Equal Channel Angular Pressing (ECAP) at 320 0 C. The microstructure and mechanical properties were studied. It has been found that ECAP refines both the grains and precipitates, thus modifies the strength and ductility of the processed alloy. After the first pass of ECAP, the yield stress improves significantly from 71 MPa to 140 MPa.

  19. Effect of oxidizing environment on mechanical properties of molybdenum and TZM

    International Nuclear Information System (INIS)

    Liu, C.T.; Anderson, S.H.; Inouye, H.

    1978-10-01

    The effect of environment on mechanical properties of molybdenum and TZM was investigated in low-pressure (1.3-mPa) oxygen at 1150 0 C. Specimens of TZM picked up oxygen and lost carbon. The oxygen concentration increases linearly with exposure time, indicating that the chemisorption of oxygen molecules at the specimen surface, rather than bulk diffusion, controls the kinetics of oxygen absorption at 1150 0 C. Specimens of TZM increase in tensile strength and decrease in ductility with increasing oxygen content. Exposed TZM loses its ductility at elevated temperatures at an oxygen level of 500 ppM. The embrittlement is due to the formation of zones or oxide precipitates, which harden the alloy and promote the brittle fracture associated with cleavage and grain-boundary separation. Unalloyed molybdenum responds to the oxidizing environment quite differently from TZM. The molybdenum (containing no active element such as Ti and Zr) showed no internal oxidation at 1150 0 C. Instead, our results indicate that a trace of oxygen penetrated into molybdenum through its grain boundaries. This penetration raises the ductile-to-brittle transition temperature of molybdenum by 200 0 C lowers the ductility above 900 0 C. The ductility of oxygen-exposed molybdenum is virtually unaffected in the temperature range from 400 to 900 0 C. A ductility minimum (10%) is observed at 1350 0 C because of dynamic embrittlement effects; that is, diffusion of oxygen to grain boundaries or crack tips where high triaxial states of stress are generated during plastic deformation. This embrittlement can be totally eliminated by an increase in strain rate

  20. Evolution of mechanical properties of silicate glasses: Impact of the chemical composition and effects of irradiation

    International Nuclear Information System (INIS)

    Barlet, Marina

    2014-01-01

    This thesis examines: (1) how the chemical composition changes the hardness, toughness, and stress corrosion cracking behavior in model pristine and (2) how external irradiation impact these properties. It is to be incorporated in the context of the storage of nuclear waste in borosilicate glass matrix, the structural integrity of which should be assessed. Eight simplified borosilicate glasses made of 3 oxides with modulated proportions (SiO 2 -B 2 O 3 -Na 2 O (SBN) have been selected and their hardness, toughness, and stress corrosion cracking behavior have been characterized prior and after irradiation. The comparative study of the non-irradiated SBN glasses provides the role played by the chemical composition. The sodium content is found to be the key parameter: As it increases, the glass plasticity increases, leading to changes in the mechanical response to strain. Hardness (Hv) and toughness (Kc) decrease since the flow under indenter increases. The analysis of the stress corrosion behavior evidences a clear shift of the SCC curves linked also to the glass plasticity. Four of the 8 simplified SBN glass systems highlight the influence of electron, light and heavy ions irradiations on the mechanical properties. Once again, the sodium content is a key parameter. It is found to inhibit the glass modification: Glasses with high sodium content are more stable. Ions irradiations highlight the predominant role of nuclear interaction in changing the glass properties. Finally, electronic interaction induced by helium and electron irradiation does not lead to the same structural/mechanical glasses variations. (author) [fr

  1. Mechanical Properties Distribution within Polypropylene Injection Molded Samples: Effect of Mold Temperature under Uneven Thermal Conditions

    Directory of Open Access Journals (Sweden)

    Sara Liparoti

    2017-11-01

    Full Text Available The quality of the polymer parts produced by injection molding is strongly affected by the processing conditions. Uncontrolled deviations from the proper process parameters could significantly affect both internal structure and final material properties. In this work, to mimic an uneven temperature field, a strong asymmetric heating is applied during the production of injection-molded polypropylene samples. The morphology of the samples is characterized by optical and atomic force microscopy (AFM, whereas the distribution of mechanical modulus at different scales is obtained by Indentation and HarmoniX AFM tests. Results clearly show that the temperature differences between the two mold surfaces significantly affect the morphology distributions of the molded parts. This is due to both the uneven temperature field evolutions and to the asymmetric flow field. The final mechanical property distributions are determined by competition between the local molecular stretch and the local structuring achieved during solidification. The cooling rate changes affect internal structures in terms of relaxation/reorganization levels and give rise to an asymmetric distribution of mechanical properties.

  2. The effect of microalloying B on the High temperature mechanical properties of Ti3Al

    International Nuclear Information System (INIS)

    Newkirk, J.W.; Feldewerth, G.B.

    1989-01-01

    This paper presents a study of the effect of adding boron to Ti 3 Al on the microstructure and high temperature tensile properties. Boron caused a large grain refinement that dominated the tensile properties at all temperatures. Particles of Ti 2 B were found in all of the boron containing alloys. TiB was found only at concentrations of 0.1% B or more

  3. Superconducting state mechanisms and properties

    CERN Document Server

    Kresin, Vladimir Z; Wolf, Stuart A

    2014-01-01

    'Superconducting State' provides a very detailed theoretical treatment of the key mechanisms of superconductivity, including the current state of the art (phonons, magnons, and plasmons). A very complete description is given of the electron-phonon mechanism responsible for superconductivity in the majority of superconducting systems, and the history of its development, as well as a detailed description of the key experimental techniques used to study the superconducting state and determine the mechanisms. In addition, there are chapters describing the discovery and properties of the key superconducting compounds that are of the most interest for science, and applications including a special chapter on the cuprate superconductors. It provides detailed treatments of some very novel aspects of superconductivity, including multiple bands (gaps), the "pseudogap" state, novel isotope effects beyond BCS, and induced superconductivity.

  4. The effect of aqueous media on the mechanical properties of fluorapatite-mullite glass-ceramics.

    Science.gov (United States)

    Mollazadeh, S; Ajalli, Siamak; Kashi, Tahereh S Jafarzadeh; Yekta, Bijan Eftekhai; Javadpour, Jafar; Jafari, S; Youssefi, Abbas; Fazel, Akbar

    2015-11-01

    To verify the effects of alternating thermal changes in aqueous media and chemical composition on mechanical properties of apatite-mullite glass-ceramics and to investigate concentration of ions eluted from glass-ceramics in aqueous media. The glass compositions were from SiO2Al2O3P2O5CaOTiO2BaOZrO2CaF2 system. Glass-ceramics were prepared by heat-treating at 1100°C for 3h samples alternately immersed in water at 5 and 60°C. The 3-point bending strength (n=10) were determined using 3×4×25mm/bar and a universal testing machine, at a cross-head speed of 0.1mm/min. Vickers micro hardness were evaluated by applying a total of 15-20 indentations under a 100g load for 30s. Concentrations of ions eluted from glass-ceramics immersed in 60±5°C double distilled water were determined by ion chromatography. The toxicity of glass-ceramics was assessed by seeding the osteosarcoma cells (MG63) on powder for different days and their cell proliferation assessment was investigated by MTT assay. The data were analyzed using one way analysis of variance and the means were compared by Tukey's test (5% significance level). The highest flexural strength and hardness values after thermal changes belonged to TiO2 and ZrO2 containing glass-ceramics which contained lower amount of released ions. BaO containing glass-ceramic and sample with extra amount of silica showed the highest amount of reduction in their mechanical strength values. These additives enhanced the concentration of eluted ions in aqueous media. MTT results showed that glass-ceramics were almost equivalent concerning their in-vitro biological behavior. Thermal changes and chemical compositions had significant effects on flexural strength and Vickers micro-hardness values. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  5. The effect of adding magnesium oxide on the mechanical properties of the tricalcium phosphate-zirconia composites

    Energy Technology Data Exchange (ETDEWEB)

    Sallemi, Imen, E-mail: imen.sallemi@hotmail.com; Bouaziz, Jamel; Ben Ayed, Foued

    2015-02-01

    The effect of magnesium oxide on the mechanical properties of the tricalcium phosphate – 50 wt.% zirconia composites was investigated during a sintering process between 1300 °C and 1400 °C. The characteristics of the samples before and after the sintering process were realized by using the differential thermal analysis, dilatometry, X-ray diffraction, the {sup 31}P magic angle scanning nuclear magnetic resonance, the scanning electron microscope and by considering such mechanical properties as the rupture strength and Vickers hardness. The mechanical performances of the tricalcium phosphate-50 wt.% zirconia composites increased with both the percentage of magnesium oxide and the sintering temperature. At 1400 °C, the mechanical properties of the composites sintered with 10 wt.% magnesium oxide reached their maximum value. Thus, Vickers hardness increased from 554 to 6350 MPa and the rupture strength of the corresponding composites varied from 5.2 to 25 MPa. The increase of the mechanical properties of the samples is due to the formation of both the tetragonal zirconia phase and the liquid phase which helps to fill the pores. The microstructure of needle form is most probably phosphate precipitates which are formed from this liquid phase. Furthermore, the presence of magnesium oxide in the composites prevented the inverse allotropic transformation of zirconia. - Highlights: • We measure the rupture strength and Vickers hardness of bioceramics. • We characterize the effect of MgO on the mechanical properties of the tricalcium phosphate – 50 wt% zirconia composites. • MgO increase the mechanical properties of the composites.

  6. Comparative effect of mechanical beating and nanofibrillation of cellulose on paper properties made from bagasse and softwood pulps.

    Science.gov (United States)

    Afra, Elyas; Yousefi, Hossein; Hadilam, Mohamad Mahdi; Nishino, Takashi

    2013-09-12

    Cellulose fibers were fibrillated using mechanical beating (shearing refiner) and ultra-fine friction grinder, respectively. The fibrillated fibers were then used to make paper. Mechanical beating process created a partial skin fibrillation, while grinding turned fiber from micro to nanoscale through nanofibrillation mechanism. The partially fibrillated and nano fibrillated fibers had significant effects on paper density, tear strength, tensile strength and water drainage time. The effect of nanofibrillation on paper properties was quantitatively higher than that of mechanical beating. Paper sheets from nanofibrillated cellulose have a higher density, higher tensile strength and lower tear strength compared to those subjected to mechanical beating. Mechanical beating and nanofibrillation were both found to be promising fiber structural modifications. Long water drainage time was an important drawback of both fibrillation methods. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Effects of heat treatments on the microstructure and mechanical properties of a 6061 aluminium alloy

    International Nuclear Information System (INIS)

    Maisonnette, D.; Suery, M.; Nelias, D.; Chaudet, P.; Epicier, T.

    2011-01-01

    Research highlight