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Sample records for aba-induced hardening conditions

  1. Development of Bake Hardening Effect by Plastic Deformation and Annealing Conditions

    Directory of Open Access Journals (Sweden)

    Kvačkaj, T.

    2006-01-01

    Full Text Available The paper deals with the classification of steel sheets for automotives industry on the basis of strength and structural characteristics. Experimental works were aimed to obtain the best possible strengthening parameters as well as work hardening and solid solution ferrite hardening, which are the result of thermal activation of interstitial carbon atoms during paint-baking of auto body. Hardening process coming from interstitial atoms is realized as two-step process. The first step is BH (bake hardening effect achieved by interaction of interstitial atoms with dislocations. The Cottrels atmosphere is obtained. The second step of BH effect is to produced the hardening from precipitation of the carbon atoms in e-carbides, or formation of Fe32C4 carbides. WH (work hardening effect is obtained as dislocation hardening from plastic deformations during sheet deep drawing. Experimental works were aimed at as to achieve such plastic material properties after cold rolling, annealing and skin-pass rolling, which would be able to classify the material ZStE220BH into the drawing categories at the level of DQ – DDQ. As resulting from the experimental results, the optimal treatment conditions for the maximal sum (WH+BH = 86 MPa are as follows: total cold rolling deformation ecold = 65 %, annealing temperature Tanneal. = 700 °C.

  2. The effect of austenitizing conditions in the ductile iron hardening process on longitudinal ultrasonic wave velocity

    Directory of Open Access Journals (Sweden)

    A. W. Orłowicz

    2014-04-01

    Full Text Available The paper presents results of a research on the effect of austenitizing temperature and time adopted in the hardening operation on the ultrasonic wave velocity in ductile iron. It has been found that with increasing austenitizing temperature and with the passage of the austenitizing time, a monotonic decrease of the ultrasonic longitudinal wave velocity value occurred. Implementation of ultrasonic testing of results obtained in the course of the cast iron hardening process both in production and as-cast conditions, requires development of a test methodology that must take into account the influence of base material structure (degree of nodularization, graphite precipitation count on the ultrasound wave velocity.

  3. Effect of Strain Hardening on Elastic-Plastic Contact of a Deformable Sphere against a Rigid Flat under Full Stick Contact Condition

    Directory of Open Access Journals (Sweden)

    Biplab Chatterjee

    2012-01-01

    Full Text Available The present study considers the effect of strain hardening on elastic-plastic contact of a deformable sphere with a rigid flat under full stick contact condition using commercial finite element software ANSYS. Different values of tangent modulus are considered to study the effect of strain hardening. It is found that under a full stick contact condition, strain hardening greatly influences the contact parameters. Comparison has also been made between perfect slip and full stick contact conditions. It is observed that the contact conditions have negligible effect on contact parameters. Studies on isotropic and kinematic hardening models reveal that the material with isotropic hardening has the higher load carrying capacity than that of kinematic hardening particularly for higher strain hardening.

  4. Forge-Hardened TiZr Null-Matrix Alloy for Neutron Scattering under Extreme Conditions

    Directory of Open Access Journals (Sweden)

    Takuo Okuchi

    2015-12-01

    Full Text Available For neutron scattering research that is performed under extreme conditions, such as high static pressures, high-strength metals that are transparent to the neutron beam are required. The diffraction of the neutron beam by the metal, which follows Bragg’s law, can be completely removed by alloying two metallic elements that have coherent scattering lengths with opposite signs. An alloy of Ti and Zr, which is known as a TiZr null-matrix alloy, is an ideal combination for such purposes. In this study, we increased the hardness of a TiZr null-matrix alloy via extensive mechanical deformation at high temperatures. We successfully used the resulting product in a high-pressure cell designed for high-static-pressure neutron scattering. This hardened TiZr null-matrix alloy may play a complementary role to normal TiZr alloy in future neutron scattering research under extreme conditions.

  5. Influence of Microstructure and Process Conditions on Simultaneous Low-Temperature Surface Hardening and Bulk Precipitation Hardening of Nanoflex®

    DEFF Research Database (Denmark)

    Bottoli, Federico; Winther, Grethe; Christiansen, Thomas L.

    2015-01-01

    Precipitation hardening martensitic stainless steel Nanoflex was low-temperature nitrided or nitrocarburized. In these treatments, simultaneous hardening of the bulk, by precipitation hardening, and the surface by dissolving nitrogen/carbon can be obtained because the treatment temperatures and t...

  6. The influence of the hardening conditions on the mechanical properties of ductile cast iron

    Directory of Open Access Journals (Sweden)

    T. Giętka

    2010-01-01

    Full Text Available Ductile cast iron has been austempered according to two variants. The first treatment variant was austenitizing at a temperature tγ = 830, 860 and 900 0C and holding at a temperature tpi = 400 and 300 0C for 8 ÷ 64 min. Second variant treatment was two-phase austenitizing. Firstly, it was heated at a temperature tγ = 950 0C and after forecooling and chilling at a temperature tγ’ = 900, 860 and 830 0C isothermal process was conducted in the same conditions as in the first variant. The cast iron with ferritic matrix was austempered. After hardening the mechanical (Rp0,2, Rm and plastic (A5 properties were examined as well as the microstructure of matrix and hardness. It was noticed that the heat treatment carried out according to variants I and II lead to attaining cast iron of grade: ADI EN-GJS-800-8, EN-GJS-1200-2, EN-GJS-1400-1 according to PN–EN 1564 : 2000; in addition, ductility of these grades was 1,5÷4 times bigger than the mini-mum standard material requirements.

  7. Effect of thermal exposure on the residual stress relaxation in a hardened cylindrical sample under creep conditions

    Science.gov (United States)

    Radchenko, V. P.; Saushkin, M. N.; Tsvetkov, V. V.

    2016-05-01

    This paper describes the effect of thermal exposure (high-temperature exposure) ( T = 675°C) on the residual creep stress relaxation in a surface hardened solid cylindrical sample made of ZhS6UVI alloy. The analysis is carried out with the use of experimental data for residual stresses after micro-shot peening and exposures to temperatures equal to T = 675°C during 50, 150, and 300 h. The paper presents the technique for solving the boundary-value creep problem for the hardened cylindrical sample with the initial stress-strain state under the condition of thermal exposure. The uniaxial experimental creep curves obtained under constant stresses of 500, 530, 570, and 600 MPa are used to construct the models describing the primary and secondary stages of creep. The calculated and experimental data for the longitudinal (axial) tensor components of residual stresses are compared, and their satisfactory agreement is determined.

  8. DNA sequence and spatial expression pattern of a drought- and ABA-induced gene in tomato

    Energy Technology Data Exchange (ETDEWEB)

    Plant, A.L.; Cohen, A.; Moses, M.S.; Bray, E.A. (Univ. of California, Riverside (United States))

    1991-05-01

    The genomic and cDNA sequence for the previously characterized drought- and ABA-induced gene pLE16 are presented. The single open reading frame contained within the gene has the capacity to encode a polypeptide of 12.7 kD with a predicted pI of 8.73. The amino-terminus is highly hydrophobic and is characteristic of signal sequences which target polypeptides for export from the cytoplasm. There is considerable homology (51.3% identity) between the amino-terminus of pLE16 and the amino-terminal domains of a group of proteins that comprise the phospholipid transfer proteins. Although this homology breaks down at the carboxy-terminal half of pLE16, the homology that exists suggests that pLE16 may be associated with membranes and may therefore play a role in maintaining membrane integrity during drought-stress. pLE16 is expressed in drought-stressed leaf, petiole and stem tissue and to a much lower extent in the seeds and pericarp of mature green tomato fruit. No expression was detected in the seeds or pericarp of red fruit or drought-stressed roots. Expression of pLE16 is induced in leaf tissue by a variety of other environmental stresses including PEG-mediated water deficit, salt, cold stress and heat stress. These stresses did not however induce expression of pLE16 in the roots. Examination of the 5{prime} flanking DNA sequences for this gene did not reveal the presence of the consensus ABA responsive element (ABRE), implicated in ABA induction of gene expression and so far common to the 5{prime} flanking DNA sequences of many genes that are ABA responsive. The expression of pLE16 in response to drought-stress and other environmental stresses in vegetative tissue, together with the lack of a consensus ABRE, suggests that the regulation of this gene by ABA may differ from those that are seed-specific.

  9. Chaboche-based cyclic material hardening models for 316 SS–316 SS weld under in-air and pressurized water reactor water conditions

    International Nuclear Information System (INIS)

    Mohanty, Subhasish; Soppet, William K.; Majumdar, Saurindranath; Natesan, Krishnamurti

    2016-01-01

    Highlights: • 316 SS–316 SS weld cyclically harden/soften while undergoing fatigue loading. • Cyclic hardening/softening creates cycle dependent stress-strain curves. • This necessitate to estimate the cycle dependence of material properties. • Cyclic evolution of Chaboche parameters are estimated under different conditions. - Abstract: This paper discusses a material hardening models for welds made from 316 stainless steel (SS) to 316 SS. The model parameters were estimated from the strain-versus-stress curves obtained from tensile and fatigue tests conducted under different conditions (air at room temperature, air at 300 °C, and primary loop water conditions for a pressurized water reactor). These data were used to check the fatigue cycle dependency of the material hardening parameters (yield stress, parameters related to Chaboche-based linear and nonlinear kinematic hardening models, etc.). The details of the experimental results, material hardening models, and associated calculated results are published in an Argonne report (ANL/LWRS-15/2). This paper summarizes the reported material parameters for 316 SS–316 SS welds and their dependency on fatigue cycles and other test conditions.

  10. Experiment-based modelling of hardening and localized plasticity in metals irradiated under cascade damage conditions

    International Nuclear Information System (INIS)

    Singh, B.N.; Ghoniem, N.M.; Trinkaus, H.

    2002-01-01

    The analysis of the available experimental observations shows that the occurrence of a sudden yield drop and the associated plastic flow localization are the major concerns regarding the performance and lifetime of materials exposed to fission or fusion neutrons. In the light of the known mechanical properties and microstructures of the as-irradiated and irradiated and deformed materials, it has been argued that the increase in the upper yield stress, the sudden yield drop and the initiation of plastic flow localization, can be rationalized in terms of the cascade induced source hardening (CISH) model. Various aspects of the model (main assumptions and predictions) have been investigated using analytical calculations, 3-D dislocation dynamics and molecular dynamics simulations. The main results and conclusions are briefly summarized. Finally, it is pointed out that even though the formation of cleared channels may be rationalized in terms of climb-controlled glide of the source dislocation, a number of problems regarding the initiation and the evolution of these channels remain unsolved

  11. Experiment-based modelling of hardening and localized plasticity in metals irradiated under cascade damage conditions

    Energy Technology Data Exchange (ETDEWEB)

    Singh, B.N. E-mail: bachu.singh@risoe.dk; Ghoniem, N.M.; Trinkaus, H

    2002-12-01

    The analysis of the available experimental observations shows that the occurrence of a sudden yield drop and the associated plastic flow localization are the major concerns regarding the performance and lifetime of materials exposed to fission or fusion neutrons. In the light of the known mechanical properties and microstructures of the as-irradiated and irradiated and deformed materials, it has been argued that the increase in the upper yield stress, the sudden yield drop and the initiation of plastic flow localization, can be rationalized in terms of the cascade induced source hardening (CISH) model. Various aspects of the model (main assumptions and predictions) have been investigated using analytical calculations, 3-D dislocation dynamics and molecular dynamics simulations. The main results and conclusions are briefly summarized. Finally, it is pointed out that even though the formation of cleared channels may be rationalized in terms of climb-controlled glide of the source dislocation, a number of problems regarding the initiation and the evolution of these channels remain unsolved.

  12. Method development to evaluate steel fiber performance in concrete with expansive additives under restrained hardening conditions: preliminary results

    Science.gov (United States)

    Lukasenoks, A.; Cepuritis, R.

    2017-10-01

    Novel steel molds in form of a rigid cubical shell were developed in order to investigate single steel fiber pull-out resistance in concrete with expansive additive under restrained hardening conditions. The developed steel molds simulate internal (from steel fibers) and external (from friction against sub-base) restraints that hinder expansion of the concrete in a flooring slab structure installed on ground. Samples with a single hooked-end steel fiber, with and without expansive additive were manufactured and tested in the developed mold geometry. The results show that restrained concrete expansion positively affects single fiber pull-out behavior, i.e. fiber delamination resistance is increased by 29.7 % and pull-out peak load by 10.8 %.

  13. Experimental research of residual stresses kinetics in the hardened hollow cylindrical specimens of D16T alloy at the axial tension under the creep conditions

    Directory of Open Access Journals (Sweden)

    Vladimir P. Radchenko

    2016-06-01

    Full Text Available We study experimentally the effect of the axial tension load on the residual stresses relaxation in the surface-hardened hollow cylindrical specimens of D16T aluminium alloy at a temperature of 125 ∘C. The surface is hardened by the air shot-peening. We describe the testing machine and the routine of experiment. The experimental curves of hardened specimens creep under the axial loads 353, 385, 406.2, 420 MPa and test duration of 100–160 hours are obtained. The axial and circumferential residual stresses after the hardening and the creep at the given temperature and load conditions are constructed by the method of circles and strips. The significant qualitative and quantitative changes of residual stresses take place under the tension load σ¯ in comparison with the thermal exposure (heat exposal with no load. The relaxation of residual stresses is essentially independent of the thermal exposure. In contrast, the loading leads to the significant residual stresses relaxation and to the changes in the distribution type. The axial and circumferential residual stresses evolve from the compressive to the tension with the increase of the axial tension load. Also the depth of residual stresses location changes with the increase of the axial tension load from the 600 microns in the original state after the air shot-peening to the 250–300 microns after the creep under the given loading. It is very important for the engineering applications to take into account the described behaviours of the residual stresses in the hardened specimens of D16T alloy when predicting the characteristics of endurance of the surface-hardened details operate under the elevated temperatures.

  14. Study of High Fluence Radiation-induced Swelling and Hardening under Light Water Reactor Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Golubov, Stanislav I. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Barashev, Alexander V. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Stoller, Roger E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-09-01

    This report documents a comprehensive model that has been developed to enable simulations of microstructural evolution under the irradiation conditions typical of light water reactor (LWR) internal components. The model, which accounts cascade production of point defects and vacancy, interstitial faulted dislocation loops, interstitial clusters migrating one-dimensionally and the evolution of the network dislocation structure, has been parameterized to account damage accumulation in austenitic stainless steels. Nucleation and growth of an ensemble of cavities is based on accounting the residual and produced by irradiation He atoms and existence of the dislocation and production biases. Additional applications and potential future developments for the model are also discussed.

  15. A hardenability test proposal

    Energy Technology Data Exchange (ETDEWEB)

    Murthy, N.V.S.N. [Ingersoll-Rand (I) Ltd., Bangalore (India)

    1996-12-31

    A new approach for hardenability evaluation and its application to heat treatable steels will be discussed. This will include an overview and deficiencies of the current methods and discussion on the necessity for a new approach. Hardenability terminology will be expanded to avoid ambiguity and over-simplification as encountered with the current system. A new hardenability definition is proposed. Hardenability specification methods are simplified and rationalized. The new hardenability evaluation system proposed here utilizes a test specimen with varying diameter as an alternative to the cylindrical Jominy hardenability test specimen and is readily applicable to the evaluation of a wide variety of steels with different cross-section sizes.

  16. Influences of Soaking Temperature and Storage Conditions on Hardening of Soybeans (Glycine max) and Red Kidney Beans (Phaseolus vulgaris).

    Science.gov (United States)

    Koriyama, Takako; Sato, Yoko; Iijima, Kumiko; Kasai, Midori

    2017-07-01

    The influences of soaking treatment and storage conditions on the softening of cooked beans, namely, soybeans and red kidney beans, were investigated. It was revealed that the softening of fresh soybeans and fresh red kidney beans was suppressed during subsequent boiling after soaking treatment at 50 and 60 °C. Furthermore, in treated aged soybeans and red kidney beans that were subjected to storage at 30 °C/75% relative humidity for 6 mo and soaking treatment at 50 to 60 °C, the hardness during cooking was further amplified. This suggested that the mechanism of softening suppression differs depending on the influences of soaking and storage. Analysis of the pectin fraction in alcohol insoluble solid showed insolubilization of metal ions upon storage at high temperature and high humidity in both soybeans and red kidney beans, which suggests interaction between Ca ions and hemicellulose or cellulose as cell wall polysaccharides. The results of differential scanning calorimetry (DSC) showed that aged soybeans exhibited a shift in the thermal transition temperature of glycinin-based protein to a higher temperature compared with fresh soybeans. From the results of DSC and scanning electron microscopy for aged red kidney beans, damaged starch is not conspicuous in the raw state after storage but is abundant upon soaking treatment. As for the influence of soaking at 60 °C, it can be suggested that its influence on cell wall crosslinking was large in soybeans and red kidney beans in both a fresh state and an aged state. © 2017 Institute of Food Technologists®.

  17. Some observations on time-hardening and strain-hardening rules for creep in Zircaloy-2

    International Nuclear Information System (INIS)

    Lucas, G.E.; Pelloux, R.M.N.

    1981-01-01

    The role of accurate creep prediction in zirconium alloys, and the Zircaloys in particular, has become increasingly important in light water reactor core component design and behavior analyses. A study was made of the applicability of time-hardening and strain-hardening rules to describe creep deformation in Zircaloy-2 under variable stress and temperature conditions. Variable stress and variable temperature creep data were compared to isotonic (iso-stress) and isothermal data in the stress regime 69 to 172 MPa and the temperature regime 325 to 400/degree/C. It was observed that creep deformation under these variable conditions does not follow a time-hardening rule. This paper formulates strain-hardening rule, which describes well the variable temperature creep deformation at temperatures up to 375/degree/C. At 400/degree/C, however, the strain-hardening rule broke down because of a nonnegligible recovery rate. 28 refs

  18. Structural heredity influence upon principles of strain wave hardening

    Science.gov (United States)

    Kiricheck, A. V.; Barinov, S. V.; Yashin, A. V.

    2017-02-01

    It was established experimentally that by penetration of a strain wave through material hardened not only the technological modes of processing, but also a technological heredity - the direction of the fibers of the original macrostructure have an influence upon the diagram of microhardness. By penetration of the strain wave along fibers, the degree of hardening the material is less, however, a product is hardened throughout its entire section mainly along fibers. In the direction of the strain waves across fibers of the original structure of material, the degree of material hardening is much higher, the depth of the hardened layer with the degree of hardening not less than 50% makes at least 3 mm. It was found that under certain conditions the strain wave can completely change the original structure of the material. Thus, a heterogeneously hardened structure characterized by the interchange of harder and more viscous areas is formed, which is beneficial for assurance of high operational properties of material.

  19. Effect of Pre-Aging Conditions on Bake-Hardening Response of Al-0.4 wt%Mg-1.2 wt%Si-0.1 wt%Mn Alloy Sheets

    International Nuclear Information System (INIS)

    Lee, Kwang-jin; Woo, Kee-do

    2011-01-01

    Pre-aging heat treatment after solution heat treatment (SHT) of Al-0.4 wt%Mg-1.2 wt%Si-0.1 wt%Mn alloy sheets for auto-bodies was carried out to investigate the effect of pre-aging and its conditions on the bake-hardening response. Mechanical properties were evaluated by a tensile and Vickers hardness test. Microstructural observation was also performed using a transmission electron microscope (TEM). It was revealed that pre-aging treatments play a great role in the bake-hardening response. In addition, it was found that the sphere-shaped nanosized clusters that can directly transit to the needle-shaped β” phase during the paint-bake process, not being dissolved into the matrix, are formed at 343 K. The result, reveals that the dominant factor of the bake-hardening response is the pre-aging temperature rather than the pre-aging time.

  20. Investigation of srawberry hardening in low temperatures in vitro

    OpenAIRE

    Lukoševičiūtė, Vanda; Rugienius, Rytis; Kavaliauskaitė, Danguolė

    2007-01-01

    Cold resistance of different strawberry varieties in vitro and ability to retain hardening after defrosting and repeated hardening. Phytohormons – gibberellin and abscisic acid added in the growing medium were investigated in Horticulture plant genetic and biotechnology department of LIH. We tried to model common conditions in temperate zone when freeze-thaw cycles often occur during wintertime. For investigation in vitro strawberries for the first time hardened in light at the temperature of...

  1. Radiation hardenable coating mixture

    International Nuclear Information System (INIS)

    Howard, D.D.

    1977-01-01

    This invention relates to coatings that harden under radiation and to their compositions. Specifically, this invention concerns unsaturated urethane resins polymerisable by addition and to compositions, hardening under the effect of radiation, containing these resins. These resins feature the presence of at least one unsaturated ethylenic terminal group of structure CH 2 =C and containing the product of the reaction of an organic isocyanate compound with at least two isocyanate groups and one polyester polyol with at least two hydroxyl groups, and one unsaturated monomer compound polymerisable by addition having a single active hydrogen group reacting with the isocyanate [fr

  2. Hardening Azure applications

    CERN Document Server

    Gaurav, Suraj

    2015-01-01

    Learn what it takes to build large scale, mission critical applications -hardened applications- on the Azure cloud platform. This 208 page book covers the techniques and engineering principles that every architect and developer needs to know to harden their Azure/.NET applications to ensure maximum reliability and high availability when deployed at scale. While the techniques are implemented in .NET and optimized for Azure, the principles here will also be valuable for users of other cloud-based development platforms. Applications come in a variety of forms, from simple apps that can be bui

  3. Analysis of the unstressed lattice spacing, d0, for the determination of the residual stress in a friction stir welded plate of an age-hardenable aluminum alloy – Use of equilibrium conditions and a genetic algorithm

    International Nuclear Information System (INIS)

    Cioffi, F.; Hidalgo, J.I.; Fernández, R.; Pirling, T.; Fernández, B.; Gesto, D.; Puente Orench, I.; Rey, P.; González-Doncel, G.

    2014-01-01

    Procedures based on equilibrium conditions (stress and bending moment) have been used to obtain an unstressed lattice spacing, d 0 , as a crucial requirement for calculating the residual stress (RS) profile across a joint conducted on a 10 mm thick plate of age-hardenable AA2024 alloy by friction stir welding (FSW). Two procedures have been used that take advantage of neutron diffraction measurements. First, equilibrium conditions were imposed on sections parallel to the weld so that a constant d 0 value corresponding to the base material region could be calculated analytically. Second, balance conditions were imposed on a section transverse to the weld. Then, using the data and a genetic algorithm, suitable d 0 values for the different regions of the weld have been found. For several reasons, the comb method has proved to be inappropriate for RS determination in the case of age-hardenable alloys. However, the equilibrium conditions, together with the genetic algorithm, has been shown to be very suitable for determining RS profiles in FSW joints of these alloys, where inherent microstructural variations of d 0 across the weld are expected

  4. Tensile and Fatigue Testing and Material Hardening Model Development for 508 LAS Base Metal and 316 SS Similar Metal Weld under In-air and PWR Primary Loop Water Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Mohanty, Subhasish [Argonne National Lab. (ANL), Argonne, IL (United States); Soppet, William [Argonne National Lab. (ANL), Argonne, IL (United States); Majumdar, Saurin [Argonne National Lab. (ANL), Argonne, IL (United States); Natesan, Ken [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-09-01

    This report provides an update on an assessment of environmentally assisted fatigue for light water reactor components under extended service conditions. This report is a deliverable in September 2015 under the work package for environmentally assisted fatigue under DOE’s Light Water Reactor Sustainability program. In an April 2015 report we presented a baseline mechanistic finite element model of a two-loop pressurized water reactor (PWR) for systemlevel heat transfer analysis and subsequent thermal-mechanical stress analysis and fatigue life estimation under reactor thermal-mechanical cycles. In the present report, we provide tensile and fatigue test data for 508 low-alloy steel (LAS) base metal, 508 LAS heat-affected zone metal in 508 LAS–316 stainless steel (SS) dissimilar metal welds, and 316 SS-316 SS similar metal welds. The test was conducted under different conditions such as in air at room temperature, in air at 300 oC, and under PWR primary loop water conditions. Data are provided on materials properties related to time-independent tensile tests and time-dependent cyclic tests, such as elastic modulus, elastic and offset strain yield limit stress, and linear and nonlinear kinematic hardening model parameters. The overall objective of this report is to provide guidance to estimate tensile/fatigue hardening parameters from test data. Also, the material models and parameters reported here can directly be used in commercially available finite element codes for fatigue and ratcheting evaluation of reactor components under in-air and PWR water conditions.

  5. Radiation-hardening coatings

    International Nuclear Information System (INIS)

    Sellmer, H.

    1989-01-01

    Lacquers and coating agents hardened by radiation have replaced conventional coating in some fields. By means of single developments (glass-fiber coating, photosensitive lacquers for films and printing plates, photoresists, additives and fillers) the latest tendencies are shown in a survey. (HP) [de

  6. RHOBOT: Radiation hardened robotics

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, P.C.; Posey, L.D. [Sandia National Labs., Albuquerque, NM (United States)

    1997-10-01

    A survey of robotic applications in radioactive environments has been conducted, and analysis of robotic system components and their response to the varying types and strengths of radiation has been completed. Two specific robotic systems for accident recovery and nuclear fuel movement have been analyzed in detail for radiation hardness. Finally, a general design approach for radiation-hardened robotics systems has been developed and is presented. This report completes this project which was funded under the Laboratory Directed Research and Development program.

  7. RHOBOT: Radiation hardened robotics

    International Nuclear Information System (INIS)

    Bennett, P.C.; Posey, L.D.

    1997-10-01

    A survey of robotic applications in radioactive environments has been conducted, and analysis of robotic system components and their response to the varying types and strengths of radiation has been completed. Two specific robotic systems for accident recovery and nuclear fuel movement have been analyzed in detail for radiation hardness. Finally, a general design approach for radiation-hardened robotics systems has been developed and is presented. This report completes this project which was funded under the Laboratory Directed Research and Development program

  8. Grind hardening process

    CERN Document Server

    Salonitis, Konstantinos

    2015-01-01

    This book presents the grind-hardening process and the main studies published since it was introduced in 1990s.  The modelling of the various aspects of the process, such as the process forces, temperature profile developed, hardness profiles, residual stresses etc. are described in detail. The book is of interest to the research community working with mathematical modeling and optimization of manufacturing processes.

  9. Preparates hardened by radiation

    International Nuclear Information System (INIS)

    Carder, C.H.; Osborn, C.L.; Hodakowski, L.E.

    1979-01-01

    Ink and coating masses hardened by radiation have proved themsleves as suitable preparates which have originated from the reaction of a poly (alcylene oxy) polyol or polyester polyol, on organic di-isocyanate and hydroxy alkyl acrylate. At temperatures between 45 and 60 0 C, 2.5 to 8.0 equivalents of the organic di-isocyanate and 1.5 to 6.0 equivalents of the hydroxy alkyl acrylate are converted for every hydroxy equivalent in polyol. 9 examples supplement the very extensive description of the fabrication possibilities. (UWI) [de

  10. Influence of impact energy on work hardening ability of austenitic manganese steel and its mechanism

    Directory of Open Access Journals (Sweden)

    Li Xiaoyun

    2012-08-01

    Full Text Available To further understand the hardening mechanism of austenitic manganese steel under actual working conditions, the work hardening ability was studied and the microstructures of austenitic manganese steel were observed under different impact energies. The work hardening mechanism was also analyzed. The results show that the best strain hardening effect could be received only when the impact energy reaches or exceeds the critical impact energy. The microstructural observations reveal that dislocations, stacking faults and twins increase with raising impact energy of the tested specimens. The hardening mechanism changes at different hardening degrees. It is mainly dislocation and slip hardening below the critical impact energy, but it changes to the twinning hardening mechanism when the impact energy is above the critical impact energy.

  11. [Microstructural changes in hardened beans (Phaseolus vulgaris)].

    Science.gov (United States)

    Mujica, Maria Virginia; Granito, Marisela; Soto, Naudy

    2015-06-01

    (Phaseolus vulgaris). The hardening of Phaseolus vulgaris beans stored at high temperature and high relative humidity is one of the main constraints for consumption. The objective of this research was to evaluate by scanning electron microscopy, structural changes in cotyledons and testa of the hardened beans. The freshly harvested grains were stored for twelve months under two conditions: 5 ° C-34% RH and 37 ° C-75% RH, in order to promote hardening. The stored raw and cooked grains were lyophilized and fractured. The sections of testa and cotyledons were observed in an electron microscope JSM-6390. After twelve months, grains stored at 37 ° C-75% RH increased their hardness by 503%, whereas there were no significant changes in grains stored at 5 ° C-34% RH. At the microstructural level, the cotyledons of the raw grains show clear differences in appearance of the cell wall, into the intercellular space size and texture matrix protein. There were also differences in compaction of palisade and sub-epidermal layer in the testa of raw grains. After cooking, cotyledon cells of the soft grains were well separated while these ofhard grains were seldom separated. In conclusion, the found differences in hard and soft grains showed a significant participation of both structures, cotyledons and testa, in the grains hardening.

  12. Hardened plungers and piston rods for high-pressure compressors

    Energy Technology Data Exchange (ETDEWEB)

    1942-07-07

    This report was a summary of information on dimensions, materials, and operating conditions, as well as experience in the use of piston rods and plungers at Gelsenkirchen. The surface hardening of these parts and their resulting life and wear were of prime importance. Nitriding hardening was one of the best processes for the production of wearproof surfaces. Case hardening and autogeneous hardening had been found satisfactory. Heat hardening had been found to be a cheap process in many applications. Surfaces could be obtained by hard chrome plating which would have the same or higher wear resistance as nitriding and excel in the depth of hardness. However, the heat hardening alone produced hard layers which had sufficiently good properties for plungers and piston rods of the booster compressors, gas-circulation pumps, paste presses, compressors and possibly pressure-release machines. This plant possessed a hardening installation which offered the advantage of production of most of the required equipment right at the works. This was particularly important if a grinding machine was available. This arrangement had to be supplemented with a shaft furnace in which parts could be heated to remove stresses before and after machining. 5 tables.

  13. Fatigue of coated and laser hardened steels

    International Nuclear Information System (INIS)

    La Cruz, P. de.

    1990-01-01

    In the present work the effect of ion nitriding, laser hardening and hot dip galvanizing upon the fatigue limit and notch sensitivity of a B-Mn Swedish steel SS 2131 have been investigated. The fatigue tests were performed in plane reverse bending fatigue (R=1). The quenched and tempered condition was taken as the reference condition. The microstructure, microhardness, fracture surface and coating appearance of the fatigue surface treated specimens were studied. Residual stress and retained austenite measurements were also carried out. It was found that ion nitriding improves the fatigue limit by 53 % for smooth specimens and by 115 % for notched specimens. Laser hardening improves the fatigue limit by 18 % and 56 % for smooth and notched specimen respectively. Hot dip galvanizing gives a slight deterioration of the fatigue limit (9 % and 10 % for smooth and notched specimen respectively). Ion nitriding and laser hardening decrease the value of the notch sensitivity factor q by 78 % and 65 % respectively. Hot dip galvanizing does not modify it. A simple schematic model based on a residual stress distribution, has been used to explain the different effects. It seems that the presence of the higher compressive residual stresses and the higher uniformity of the microstructure may be the causes of the better fatigue performance of ion nitrided specimens. (119 refs.) (author)

  14. Surface hardening of AISI 4340 steel by electron beam treatment

    International Nuclear Information System (INIS)

    Wang Chienchun; Hwang Jiunren

    1994-01-01

    This paper investigates the effect of electron beam (EB) surface hardening on the abrasive wear property of AISI 4340 steel. The heat treatment conditions were varied so that the influence of microstructures on the wear resistance could be evaluated. A dry sand/rubber wheel abrasion test was selected to evaluate the high stress wear properties. The results show that the weight loss decreases with increasing hardness of surface layer or base material. The EB surface hardening can improve the abrasive wear resistance by about 10%. The best heat treatment process for AISI 4340 steel against abrasive wear is oil quenching from 840 C, tempering at 370 C, the EB surface hardening under heat input of 135-150 J mm -1 . The width and depth of the wear tracks are reduced after the EB surface hardening treatment. (orig.)

  15. NEW APPROACH FOR TECHNOLOGY OF VOLUMETRIC – SUPERFICIAL HARDENING OF GEAR DETAILS OF THE BACK AXLE OF MOBILE MACHINES

    Directory of Open Access Journals (Sweden)

    A. I. Mihluk

    2010-01-01

    Full Text Available The new approach for technology of volumetric – superficial hardening of gear details of the back axle made of steel lowered harden ability is offered. This approach consisting in formation of intense – hardened condition on all surface of a detail.

  16. The Surface Layer Mechanical Condition and Residual Stress Forming Model in Surface Plastic Deformation Process with the Hardened Body Effect Consideration

    Science.gov (United States)

    Mahalov, M. S.; Blumenstein, V. Yu

    2017-10-01

    The mechanical condition and residual stresses (RS) research and computational algorithms creation in complex types of loading on the product lifecycle stages relevance is shown. The mechanical state and RS forming finite element model at surface plastic deformation strengthening machining, including technological inheritance effect, is presented. A model feature is the production previous stages obtained transformation properties consideration, as well as these properties evolution during metal particles displacement through the deformation space in the present loading step.

  17. Devising Strain Hardening Models Using Kocks–Mecking Plots—A Comparison of Model Development for Titanium Aluminides and Case Hardening Steel

    Directory of Open Access Journals (Sweden)

    Markus Bambach

    2016-08-01

    Full Text Available The present study focuses on the development of strain hardening models taking into account the peculiarities of titanium aluminides. In comparison to steels, whose behavior has been studied extensively in the past, titanium aluminides possess a much larger initial work hardening rate, a sharp peak stress and pronounced softening. The work hardening behavior of a TNB-V4 (Ti–44.5Al–6.25Nb–0.8Mo–0.1B alloy is studied using isothermal hot compression tests conducted on a Gleeble 3500 simulator, and compared to the typical case hardening steel 25MoCrS4. The behavior is analyzed with the help of the Kocks-Mecking plots. In contrast to steel the TNB-V4 alloy shows a non-linear course of θ (i.e., no stage-III hardening initially and exhibits neither a plateau (stage IV hardening nor an inflection point at all deformation conditions. The present paper describes the development and application of a methodology for the design of strain hardening models for the TNB-V4 alloy and the 25CrMoS4 steel by taking the course of the Kocks-Mecking plots into account. Both models use different approaches for the hardening and softening mechanisms and accurately predict the flow stress over a wide range of deformation conditions. The methodology may hence assist in further developments of more sophisticated physically-based strain hardening models for TiAl-alloys.

  18. Design and implementation of a radiation hardened silicon on sapphire (SOS) embedded signal conditioning unit controller (SCUC) for the RAPID instrument on the Cluster satellites

    International Nuclear Information System (INIS)

    Ersland, L.

    1992-07-01

    The Cluster mission consistens of four spacecrafts equipped with instruments capable of making comprehensive measurements of plasma particles and electromagnetic fields. The RAPID (Research with Adaptive Particle Imaging Detectors) spectrometer is one of many instruments on board the Cluster satellites. It is designed for fast analysis of energetic electrons and ions with a complete coverage of the unit sphere in phase space. This thesis describes the development and testing of an embedded controller for the Spectroscopic Camera for Electrons, Neutral and Ion Compositions (SCENIC), which is a part of the RAPID instrument. The design is implemented in two different CMOS circuit technologies, namely Actel's Field Programmable Gate Arrays and GEC Plessey's CMOS Silicon On Sapphire (SOS) gate array. The prototypes of the SOS gate array have been verified and characterized. This includes measurements of DC and AC parameters under different conditions, including total dose of gamma irradiation. 42 refs., 92 figs., 44 tabs

  19. Radiation-hardenable diluents for radiation-hardenable compositions

    International Nuclear Information System (INIS)

    Schuster, K.E.; Rosenkranz, H.J.; Furh, K.; Ruedolph, H.

    1979-01-01

    Radiation-crosslinkable diluents for radiation-hardenable compositions (binders) consisting of a mixture of triacrylates of a reaction product of trimethylol propane and ethylene oxide with an average degree of ethoxylation of from 2.5 to 4 are described. The ethoxylated trimethylol propane is substantially free from trimethylol propane and has the following distribution: 4 to 5% by weight of monoethoxylation product, 14 to 16% by weight of diethoxylation product, 20 to 30% by weight of triethoxylation product, 20 to 30% by weight of tetraethoxylation product, 16 to 18% by weight of pentaethoxylation product, and 6 to 8% by weight of hexaethoxylation product. The diluents effectively reduce the viscosity of radiation-hardenable compositions and do not have any adverse effect upon their reactivity or upon the properties of the resulting hardened products

  20. Hardened technologies for hazardous environments

    International Nuclear Information System (INIS)

    Dawes, W.R. Jr.

    1987-01-01

    The complete radiation environment of neutrons, total dose, transient ionizing radiation, and energetic cosmic rays (SEU) can have various deleterious effects upon semiconductor electronic components. However, hardening techniques for these radiation effects have been developed for the various semiconduct technologies that will permit their use even in severe radiation environments. The process techniques are occasionally line dependent and may require modification to achieve the desired hardness goal. Similarly, hardening semiconductor components for elevated thermal operation can be achieved with process techniques which, unlike the radiation case, are readily transferable between process lines. Radiation effects and hardening technologies are discussed for Metal Oxide Semiconductor (MOS), Bipolar, Junction Field Effect Transistors (JFET), Metal Semiconductor Field Effect Transistor (MESFET), Diode, Electro-optic, and crystal technologies. 44 refs., 44 figs

  1. Induction Hardening of Ferromagnetic Bodies

    Czech Academy of Sciences Publication Activity Database

    Barglik, J.; Doležel, Ivo; Škopek, M.; Ulrych, B.

    č. 1 (2002), s. 28-29 ISSN 0340-3521 R&D Projects: GA ČR GA102/01/0184; GA MŠk ME 542 Grant - others:PSC(PL) 7T08603716 Keywords : Induction heating * induction hardening * ferromagnetic bodies Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  2. Nonlinear kinematic hardening under non-proportional loading

    International Nuclear Information System (INIS)

    Ottosen, N.S.

    1979-07-01

    Within the framework of conventional plasticity theory, it is first determined under which conditions Melan-Prager's and Ziegler's kinematic hardening rules result in identical material behaviour. Next, assuming initial isotropy and adopting the von Mises yield criterion, a nonlinear kinematic hardening function is proposed for prediction of metal behaviour. The model assumes that hardening at a specific stress point depends on the direction of the new incremental loading. Hereby a realistic response is obtained for general reversed loading, and a smooth behaviour is assured, even when loading deviates more and more from proportional loading and ultimately results in reversed loading. The predictions of the proposed model for non-proportional loading under plane stress conditions are compared with those of the classical linear kinematic model, the isotropic model and with published experimental data. Finally, the limitations of the proposaed model are discussed. (author)

  3. Process design of press hardening with gradient material property influence

    International Nuclear Information System (INIS)

    Neugebauer, R.; Schieck, F.; Rautenstrauch, A.

    2011-01-01

    Press hardening is currently used in the production of automotive structures that require very high strength and controlled deformation during crash tests. Press hardening can achieve significant reductions of sheet thickness at constant strength and is therefore a promising technology for the production of lightweight and energy-efficient automobiles. The manganese-boron steel 22MnB5 have been implemented in sheet press hardening owing to their excellent hot formability, high hardenability, and good temperability even at low cooling rates. However, press-hardened components have shown poor ductility and cracking at relatively small strains. A possible solution to this problem is a selective increase of steel sheet ductility by press hardening process design in areas where the component is required to deform plastically during crash tests. To this end, process designers require information about microstructure and mechanical properties as a function of the wide spectrum of cooling rates and sequences and austenitizing treatment conditions that can be encountered in production environments. In the present work, a Continuous Cooling Transformation (CCT) diagram with corresponding material properties of sheet steel 22MnB5 was determined for a wide spectrum of cooling rates. Heating and cooling programs were conducted in a quenching dilatometer. Motivated by the importance of residual elasticity in crash test performance, this property was measured using a micro-bending test and the results were integrated into the CCT diagrams to complement the hardness testing results. This information is essential for the process design of press hardening of sheet components with gradient material properties.

  4. Process design of press hardening with gradient material property influence

    Science.gov (United States)

    Neugebauer, R.; Schieck, F.; Rautenstrauch, A.

    2011-05-01

    Press hardening is currently used in the production of automotive structures that require very high strength and controlled deformation during crash tests. Press hardening can achieve significant reductions of sheet thickness at constant strength and is therefore a promising technology for the production of lightweight and energy-efficient automobiles. The manganese-boron steel 22MnB5 have been implemented in sheet press hardening owing to their excellent hot formability, high hardenability, and good temperability even at low cooling rates. However, press-hardened components have shown poor ductility and cracking at relatively small strains. A possible solution to this problem is a selective increase of steel sheet ductility by press hardening process design in areas where the component is required to deform plastically during crash tests. To this end, process designers require information about microstructure and mechanical properties as a function of the wide spectrum of cooling rates and sequences and austenitizing treatment conditions that can be encountered in production environments. In the present work, a Continuous Cooling Transformation (CCT) diagram with corresponding material properties of sheet steel 22MnB5 was determined for a wide spectrum of cooling rates. Heating and cooling programs were conducted in a quenching dilatometer. Motivated by the importance of residual elasticity in crash test performance, this property was measured using a micro-bending test and the results were integrated into the CCT diagrams to complement the hardness testing results. This information is essential for the process design of press hardening of sheet components with gradient material properties.

  5. General analytical shakedown solution for structures with kinematic hardening materials

    Science.gov (United States)

    Guo, Baofeng; Zou, Zongyuan; Jin, Miao

    2016-09-01

    The effect of kinematic hardening behavior on the shakedown behaviors of structure has been investigated by performing shakedown analysis for some specific problems. The results obtained only show that the shakedown limit loads of structures with kinematic hardening model are larger than or equal to those with perfectly plastic model of the same initial yield stress. To further investigate the rules governing the different shakedown behaviors of kinematic hardening structures, the extended shakedown theorem for limited kinematic hardening is applied, the shakedown condition is then proposed, and a general analytical solution for the structural shakedown limit load is thus derived. The analytical shakedown limit loads for fully reversed cyclic loading and non-fully reversed cyclic loading are then given based on the general solution. The resulting analytical solution is applied to some specific problems: a hollow specimen subjected to tension and torsion, a flanged pipe subjected to pressure and axial force and a square plate with small central hole subjected to biaxial tension. The results obtained are compared with those in literatures, they are consistent with each other. Based on the resulting general analytical solution, rules governing the general effects of kinematic hardening behavior on the shakedown behavior of structure are clearly.

  6. THE MACHINING OF HARDENED CARBON STEELS BY COATED CUTTING TOOLS

    Directory of Open Access Journals (Sweden)

    Yusuf ŞAHİN

    2001-02-01

    Full Text Available The investigation of machining AISI 1050 carbon steels hardened to the 60 HRC hardness was carried out to determine the tool life and wear behaviour of the various cutting tools under different conditions. These experiments were conducted at using coated ceramic cutting tools and carbide cutting tools. The experimental results showed that the coated ceramic tools exhibited better performance than those of the coated carbide tools when machining the hardened steels. Moreover, wear behaviour of cutting tools were investigated in a scanning electron microscope. Electron microscopic examination also indicated that flank wear, thermal cracks on the tool nose combined with the nose deformation on the tools were responsible for the wear behaviour of the ceramic tools. For the carbide tools, however, removal of coated material from the substrate tool and combined with the crater wear were effective for the machining the hardened steel.

  7. Scintillation-Hardened GPS Receiver

    Science.gov (United States)

    Stephens, Donald R.

    2015-01-01

    CommLargo, Inc., has developed a scintillation-hardened Global Positioning System (GPS) receiver that improves reliability for low-orbit missions and complies with NASA's Space Telecommunications Radio System (STRS) architecture standards. A software-defined radio (SDR) implementation allows a single hardware element to function as either a conventional radio or as a GPS receiver, providing backup and redundancy for platforms such as the International Space Station (ISS) and high-value remote sensing platforms. The innovation's flexible SDR implementation reduces cost, weight, and power requirements. Scintillation hardening improves mission reliability and variability. In Phase I, CommLargo refactored an open-source GPS software package with Kalman filter-based tracking loops to improve performance during scintillation and also demonstrated improved navigation during a geomagnetic storm. In Phase II, the company generated a new field-programmable gate array (FPGA)-based GPS waveform to demonstrate on NASA's Space Communication and Navigation (SCaN) test bed.

  8. Biological hardening and genetic fidelity testing of micro-cloned ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-04-17

    Apr 17, 2008 ... vitro conditions as the cultured plants have non functional stomata, weak root system and poorly developed ... propagation techniques in C. borivilianum have so far met with limited success because of high ..... Biological hardening of tissue culture raised tea plants through rhizosphere bacteria. Biotechnol.

  9. Simultaneous surface engineering and bulk hardening of precipitation hardening stainless steel

    DEFF Research Database (Denmark)

    Frandsen, Rasmus Berg; Christiansen, Thomas; Somers, Marcel A. J.

    2006-01-01

    This article addresses simultaneous bulk precipitation hardening and low temperature surface engineering of two commercial precipitation hardening stainless steels: Sandvik Nanoflex® and Uddeholm Corrax®. Surface engineering comprised gaseous nitriding or gaseous carburising. Microstructural char....... The duration and temperature of the nitriding/carburising surface hardening treatment can be chosen in agreement with the thermal treatment for obtaining optimal bulk hardness in the precipitation hardening stainless steel.......This article addresses simultaneous bulk precipitation hardening and low temperature surface engineering of two commercial precipitation hardening stainless steels: Sandvik Nanoflex® and Uddeholm Corrax®. Surface engineering comprised gaseous nitriding or gaseous carburising. Microstructural...

  10. Instabilities in power law gradient hardening materials

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Tvergaard, Viggo

    2005-01-01

    Tension and compression instabilities are investigated for specimens with dimensions in the micron range. A finite strain generalization of a higher order strain gradient plasticity theory is implemented in a finite element scheme capable of modeling power law hardening materials. Effects...... of gradient hardening are found to delay the onset of localization under plane strain tension, and significantly reduce strain gradients in the localized zone. For plane strain compression gradient hardening is found to increase the load-carrying capacity significantly....

  11. Induction Hardening of External Gear

    Science.gov (United States)

    Bukanin, V. A.; Ivanov, A. N.; Zenkov, A. E.; Vologdin, V. V.; Vologdin, V. V., Jr.

    2018-03-01

    Problems and solution of gear induction hardening are described. Main attention is paid to the parameters of heating and cooling systems. ELTA 7.0 program has been used to obtain the required electrical parameters of inductor, power sources, resonant circuits, as well as to choose the quenching media. Comparison of experimental and calculated results of investigation is provided. In order to compare advantages and disadvantages of single- and dual-frequency heating processes, many variants of these technologies were simulated. The predicted structure and hardness of steel gears are obtained by use of the ELTA data base taken into account the Continuous Cooling Transformation diagrams.

  12. Optimization of resistively hardened latches

    International Nuclear Information System (INIS)

    Gagne, G.; Savaria, Y.

    1990-01-01

    The design of digital circuits tolerant to single-event upsets is considered. The results of a study are presented on which an analytical model was used to predict the behavior of a standard resistively hardened latch. It is shown that a worst case analysis for all possible single-event upset situations (on the latch or in the logic) can be derived from studying the effects of a transient disturbed write cycle. The existence of an intrinsic minimum write period to tolerate a transient of a given duration is also demonstrated

  13. A unified theoretical and experimental study of anisotropic hardening

    International Nuclear Information System (INIS)

    Boehler, J.P.; Raclin, J.

    1981-01-01

    The purpose of this work is to develop a consistent formulation of the constitutive relations regarding anisotropic hardening materials. Attention is focused on the appearance and the evolution of mechanical anisotropies during irreversible processes, such as plastic forming and inelastic deformation of structures. The representation theorems for anisotropic tensor functions constitute a theoretical basis, allowing to reduce arbitrariness and to obtain a unified formulation of anisotropic hardening. In this approach, a general three-dimensional constitutive law is developed for prestrained initially orthotropic materials. Introduction of the plastic behavior results in the general forms of both the flow-law and the yield criterion. The developed theory is then specialized for the case of plane stress and different modes of anisotropic hardening are analyzed. A new generalization of the Von Mises criterion is proposed, in considering a homogeneous form of order two in stress and employing the simplest combinations of the basic invariants entering the general form of the yield condition. The proposed criterion involves specific terms accounting for the initial anisotropy, the deformation induced anisotropy and correlative terms between initial and induced anisotropy. The effects of prestrainings result in both isotropic and anisotropic hardening. An adequate experimental program, consisting of uniaxial tensile tests on oriented specimens of prestrained sheet-metal, was performed, in order to determine the specific form and the evolution of the anisotropic failure criterion for soft-steel subjected to different irreversible prestrainings. (orig.)

  14. Mechanisms and environmental signals triggering frost hardening ...

    Indian Academy of Sciences (India)

    2004-10-28

    Oct 28, 2004 ... Home; Journals; Journal of Biosciences; Volume 29; Issue 4. Plant resistance to cold stress: Mechanisms and environmental signals triggering frost hardening and dehardening ... Keywords. Cold acclimation of plants; environmental signals; frost hardening; photoperiod; phytochrome; Scots pine ...

  15. Radiation hardening of integrated circuits technologies

    International Nuclear Information System (INIS)

    Auberton-Herve, A.J.; Leray, J.L.

    1991-01-01

    The radiation hardening studies started in the mid decade -1960-1970. To survive the different military or space radiative environment, a new engineering science borned, to understand the degradation of electronics components. The different solutions to improve the electronic behavior in such environment, have been named radiation hardening of the technologies. Improvement of existing technologies, and qualification method have been widely studied. However, at the other hand, specific technologies was developped : The Silicon On Insulator technologies for CMOS or Bipolar. The HSOI3HD technology (supported by DGA-CEA DAM and LETI with THOMSON TMS) offers today the highest hardening level for the integration density of hundreds of thousand transistors on the same silicon. Full complex systems would be realized on a single die with a technological radiation hardening and no more system hardening

  16. Radiation hardening of smart electronics

    International Nuclear Information System (INIS)

    Mayo, C.W.; Cain, V.R.; Marks, K.A.; Millward, D.G.

    1991-02-01

    Microprocessor based ''smart'' pressure, level, and flow transmitters were tested to determine the radiation hardness of this class of electronic instrumentation for use in reactor building applications. Commercial grade Complementary Metal Oxide Semiconductor (CMOS) integrated circuits used in these transmitters were found to fail at total gamma dose levels between 2500 and 10,000 rad. This results in an unacceptably short lifetime in many reactor building radiation environments. Radiation hardened integrated circuits can, in general, provide satisfactory service life for normal reactor operations when not restricted to the extremely low power budget imposed by standard 4--20 mA two-wire instrument loops. The design of these circuits will require attention to vendor radiation hardness specifications, dose rates, process control with respect to radiation hardness factors, and non-volatile programmable memory technology. 3 refs., 2 figs

  17. Structural aspects of materials hardening

    International Nuclear Information System (INIS)

    Naberenkov, A.V.; Fabritsiev, S.A.

    1996-01-01

    Dispersion-strengthened (DS) and precipitation-hardened (PH) copper-based alloys are suggested to be used for energy-strained components in the ITER discharge chambers. But, the stability of their properties remains still uncertain. It is evident, that of critical importance here is the stability of the composition and the morphology of disperse particles under irradiation. Also of importance is the coherent or noncoherent character of the impurity particle bonding with the lattice. In this work the impact of the size and density of fine inclusions into the matrix on the material yield strength for the DS alloys Cu-Mo and MAGT-0.2 was analyzed. The particle density is shown to be crucial in strengthening. At the same time the bonding of particles with the matrix is of minor importance. (orig.)

  18. Model and numerical analysis of mechanical phenomena of tools steel hardening

    Directory of Open Access Journals (Sweden)

    A. Bokota

    2010-01-01

    Full Text Available This paper the model hardening of tool steel takes into considerations of mechanical phenomena is presented. Fields stresses and strains are obtained from solutions by FEM equilibrium equations in rate form. The stresses generated during hardening were assumed to result from thermal load, structural deformation, and plastic deformation and transformation plasticity. Thermophysical values in the constitutive relations are depended upon both the temperature and the phase composition. Condition Huber-Misses with the isotropic strengthening for the creation of plastic strains is used. However model Leblond to determined transformations plasticity applied. The analysis of stresses associated of the elements hardening made of tool steel was done.

  19. Local hardening evaluation of carbon steels by using frequency sweeping excitation and spectrogram method

    Science.gov (United States)

    Tsuchida, Yuji; Kudo, Yuki; Enokizono, Masato

    2017-02-01

    This paper presents our proposed frequency sweeping excitation and spectrogram method (FSES method) by a magnetic sensor for non-destructive testing of hardened low carbon steels. This method can evaluate the magnetic properties of low carbon steels which were changed after induction heating treatment. It was examined by our proposed method that the degrees of yield strength of low carbon steels were varied depending on hardened conditions. Moreover, it was made clear that the maximum magnetic field strength, Hmax, derived from the measured B-H loops was very sensitive to the hardening if the surface of the samples were flat.

  20. Fusion zone microstructure evolution of fiber laser welded press-hardened steels

    International Nuclear Information System (INIS)

    Saha, Dulal Chandra; Biro, Elliot; Gerlich, Adrian P.; Zhou, Norman Y.

    2016-01-01

    Fusion zone microstructures of fiber laser welded Al-Si coated press-hardened steels at pre- and post-press-hardened conditions were analyzed using transmission electron microscopy (TEM). TEM and nanoindentation studies suggest that dislocation-free δ-ferrite phase formed in the weld metal (by ingress of the Al-Si surface coating into the fusion zone) exhibits lower nanohardness compared to α-ferrite transformed after press hardening. The nanoscale properties of δ-ferrite, α-ferrite, and martensite and their crystallographic orientation relationships are reported.

  1. Structural characterisation of oxygen diffusion hardened alpha-tantalum PVD-coatings on titanium.

    Science.gov (United States)

    Hertl, C; Koll, L; Schmitz, T; Werner, E; Gbureck, U

    2014-08-01

    Titanium substrates were coated with tantalum layers of 5 μm thickness using physical vapour deposition (PVD). The tantalum layers showed a (110)-preferred orientation. The coated samples were hardened by oxygen diffusion. Using X-ray diffraction the crystallographic structure of the tantalum coatings was characterised, comparing untreated and diffusion hardened specimen conditions. Oxygen depth profiles were determined by glow discharge spectrometry. The hardening effect of the heat treatment was examined by Vickers microhardness testing. The increase of surface hardness caused by oxygen diffusion was at least 50%. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. 3-D Temperature and Stress Simulations of Hardening Concrete

    DEFF Research Database (Denmark)

    Jensen, Poul; Buhr, Birit; Thorborg, Jesper

    2003-01-01

    When concrete is cast, heat develops. When the concrete cools down there is a risk that thermal gradients induce cracks in the structure. In the Middle East this is especially important as extensive heat builds up due to the high ambient temperatures. Possible formed cracks will have a detrimental...... effect on the overall durability of the structure, especially when placed in or close to a marine environment, and especially if placed in a hot and aggressive environment. In order to minimize the risk of inducing thermal cracks, temperature and stress requirements during the hardening period must...... for the thermo-mechanical conditions during hydration of early age concrete. Material properties as a function of maturity and environmental conditions form the basis of the model. This paper presents temperature and stress calculation results using MAGMAconcrete, and proposed hardening precautions for two...

  3. Laser Surface Hardening of Groove Edges

    Science.gov (United States)

    Hussain, A.; Hamdani, A. H.; Akhter, R.; Aslam, M.

    2013-06-01

    Surface hardening of groove-edges made of 3Cr13 Stainless Steel has been carried out using 500 W CO2 laser with a rectangular beam of 2.5×3 mm2. The processing speed was varied from 150-500 mm/min. It was seen that the hardened depth increases with increase in laser interaction time. A maximum hardened depth of around 1mm was achieved. The microhardness of the transformed zone was 2.5 times the hardness of base metal. The XRD's and microstructural analysis were also reported.

  4. Total ionizing dose effects and hardening techniques of anti-fuse FPGAs

    CERN Document Server

    Zhao Ju Chao

    2002-01-01

    Total ionizing dose hardening of commercial FPGAs for space applications is presented briefly. Total ionizing dose effects of Actel anti-fuse FPGAs are analysed in detail, including effects of fabrication technologies, bias condition and charge pump. The results show that degradation of the internal charge pump is a key factor in severe degradation of the systems. It is vitally important that radiation testing should include special measurements of start-up transients. Lastly, available hardening techniques are discussed

  5. Laser surface alloying of 316L stainless steel : different hardening routes and related microstructures

    OpenAIRE

    Laroudie, F.; Tassin, C.; Pons, M.

    1994-01-01

    The goal of this study is to investigate different hardening routes for 316L stainless steel by laser surface alloying. We have investigated the incorporation of hard submicronic particles of Tic, the precipitation of titanium carbide from mixtures of Ti and SiC and the formation of iron-chromium carbides by carbon incorporation. For each hardening route we present the microstructure and the hardness of the processed surface alloys and the conditions leading to the best compromise between hig...

  6. A Novel Heat Treatment Process for Surface Hardening of Steel: Metal Melt Surface Hardening

    Science.gov (United States)

    Fu, Yong-sheng; Zhang, Wei; Xu, Xiaowei; Li, Jiehua; Li, Jun; Xia, Mingxu; Li, Jianguo

    2017-09-01

    A novel heat treatment process for surface hardening of steel has been demonstrated and named as "metal melt surface hardening (MMSH)." A surface layer with a thickness of about 400 μm and a hardness of about 700 HV has been achieved by ejecting AISI 304 stainless steel melt at a temperature of about 1783 K (1510 °C) onto the 40Cr steel surface. This proposed MMSH provides a very promising application for surface hardening of steel.

  7. An energy-based beam hardening model in tomography

    Energy Technology Data Exchange (ETDEWEB)

    Casteele, E van de; Dyck, D van; Sijbers, J; Raman, E [Vision Lab, Physics Departement, University of Antwerp (RUCA) (Belgium)

    2002-12-07

    As a consequence of the polychromatic x-ray source, used in micro-computer tomography ({mu}CT) and in medical CT, the attenuation is no longer a linear function of absorber thickness. If this nonlinear beam hardening effect is not compensated, the reconstructed images will be corrupted by cupping artefacts. In this paper, a bimodal energy model for the detected energy spectrum is presented, which can be used for reduction of artefacts caused by beam hardening in well-specified conditions. Based on the combination of the spectrum of the source and the detector efficiency, the assumption is made that there are two dominant energies which can describe the system. The validity of the proposed model is examined by fitting the model to the experimental datapoints obtained on a microtomograph for different materials and source voltages.

  8. An energy-based beam hardening model in tomography

    International Nuclear Information System (INIS)

    Casteele, E van de; Dyck, D van; Sijbers, J; Raman, E

    2002-01-01

    As a consequence of the polychromatic x-ray source, used in micro-computer tomography (μCT) and in medical CT, the attenuation is no longer a linear function of absorber thickness. If this nonlinear beam hardening effect is not compensated, the reconstructed images will be corrupted by cupping artefacts. In this paper, a bimodal energy model for the detected energy spectrum is presented, which can be used for reduction of artefacts caused by beam hardening in well-specified conditions. Based on the combination of the spectrum of the source and the detector efficiency, the assumption is made that there are two dominant energies which can describe the system. The validity of the proposed model is examined by fitting the model to the experimental datapoints obtained on a microtomograph for different materials and source voltages

  9. Irradiation hardening of pure tungsten exposed to neutron irradiation

    Science.gov (United States)

    Hu, Xunxiang; Koyanagi, Takaaki; Fukuda, Makoto; Kumar, N. A. P. Kiran; Snead, Lance L.; Wirth, Brian D.; Katoh, Yutai

    2016-11-01

    Pure tungsten samples have been neutron irradiated in HFIR at 90-850 °C to 0.03-2.2 dpa. A dispersed barrier hardening model informed by the available microstructure data has been used to predict the hardness. Comparison of the model predictions and the measured Vickers hardness reveals the dominant hardening contribution at various irradiation conditions. For tungsten samples irradiated in HFIR, the results indicate that voids and dislocation loops contributed to the hardness increase in the low dose region (0.6 dpa). The precipitate contribution is most pronounced for the HFIR irradiations, whereas the radiation-induced defect cluster microstructure can rationalize the entirety of the hardness increase observed in tungsten irradiated in the fast neutron spectrum of Joyo and the mixed neutron spectrum of JMTR.

  10. The influence of loading rates on hardening effects in elasto/viscoplastic strain-hardening materials

    Science.gov (United States)

    De Angelis, Fabio; Cancellara, Donato; Grassia, Luigi; D'Amore, Alberto

    2018-01-01

    In this paper the influence of increasing loading rates on hardening effects is analyzed for rate-dependent elastoplastic materials. The effects of different loading rates on hardening rules are discussed with regard to the constitutive behavior of strain-hardening materials in elasto/viscoplasticity. A suitable procedure for the numerical simulation of rate-sensitive material behavior is illustrated. A comparative analysis is presented on constitutive relations in strain-hardening plasticity without rate effects and with rate effects in order to show the different role played by hardening rules in the rate-sensitivity analysis of elasto/viscoplastic strain-hardening materials. By reporting suitable numerical simulations for the adopted constitutive relations it is shown that when the rate of application of the loading is increased the influence of hardening has a different effect in the mechanical behavior of structures. Computational results and applications are finally illustrated in order to show numerically the different role played by hardening on the plastic strains when the loading rates are incremented for elasto/viscoplastic strain-hardening materials and structures.

  11. Microstrain in dispersion-hardened steels

    International Nuclear Information System (INIS)

    Bokuchava, G.D.; Papushkin, I.V.; Sumin, V.V.; Aznabaev, D.; Mukhametuly, B.; Balagurov, A.M.; Sheptyakov, D.V.

    2013-01-01

    Using high-resolution neutron diffraction, microstrain was investigated in three series of samples of stainless austenitic dispersion-hardened steels, which are used as various structural reactor components. The effect of temperature and duration of heat treatment on the precipitation of dispersion-hardened phase particles, as well as on lattice parameter changes and microstrain, was studied. In all studied steels an increase in microstrain at coherence failure was observed

  12. Decline in Radiation Hardened Microcircuit Infrastructure

    Science.gov (United States)

    LaBel, Kenneth A.

    2015-01-01

    Two areas of radiation hardened microcircuit infrastructure will be discussed: 1) The availability and performance of radiation hardened microcircuits, and, and 2) The access to radiation test facilities primarily for proton single event effects (SEE) testing. Other areas not discussed, but are a concern include: The challenge for maintaining radiation effects tool access for assurance purposes, and, the access to radiation test facilities primarily for heavy ion single event effects (SEE) testing. Status and implications will be discussed for each area.

  13. Microstrain in dispersion-hardened steels

    Science.gov (United States)

    Bokuchava, G. D.; Papushkin, I. V.; Sumin, V. V.; Aznabayev, D.; Mukhametuly, B.; Balagurov, A. M.; Sheptyakov, D. V.

    2013-03-01

    Using high-resolution neutron diffraction, microstrain was investigated in three series of samples of stainless austenitic dispersion-hardened steels, which are used as various structural reactor components. The effect of temperature and duration of heat treatment on the precipitation of dispersion-hardened phase particles, as well as on lattice parameter changes and microstrain, was studied. An increase in microstrain upon coherence failure was observed in all the steels.

  14. COMPLEX SURFACE HARDENING OF STEEL ARTICLES

    Directory of Open Access Journals (Sweden)

    A. V. Kovalchuk

    2014-01-01

    Full Text Available The method of complex surface hardening of steel detailswas designed. The method is a compound of two processes of hardening: chemical heat treatment and physical vapor deposition (PVD of the coating. The result, achieved in this study is much higher, than in other work on this topic and is cumulative. The method designed can be used in mechanical engineering, medicine, energetics and is perspective for military and space technologies.

  15. Plastic limit analysis with non linear kinematic strain hardening for metalworking processes applications

    International Nuclear Information System (INIS)

    Chaaba, Ali; Aboussaleh, Mohamed; Bousshine, Lahbib; Boudaia, El Hassan

    2011-01-01

    Limit analysis approaches are widely used to deal with metalworking processes analysis; however, they are applied only for perfectly plastic materials and recently for isotropic hardening ones excluding any kind of kinematic hardening. In the present work, using Implicit Standard Materials concept, sequential limit analysis approach and the finite element method, our objective consists in extending the limit analysis application for including linear and non linear kinematic strain hardenings. Because this plastic flow rule is non associative, the Implicit Standard Materials concept is adopted as a framework of non standard plasticity modeling. The sequential limit analysis procedure which considers the plastic behavior with non linear kinematic strain hardening as a succession of perfectly plastic behavior with yielding surfaces updated after each sequence of limit analysis and geometry updating is applied. Standard kinematic finite element method together with a regularization approach is used for performing two large compression cases (cold forging) in plane strain and axisymmetric conditions

  16. Numerical predicting of the structure and stresses state in hardened element made of tool steel

    Directory of Open Access Journals (Sweden)

    A. Bokota

    2008-03-01

    Full Text Available The paper presents numerical model of thcrmal phcnomcna, phasc transformation and mcchanical phcnomcna associated with hardeningof carbon tool steel. Model for evaluation or fractions OF phases and their kinetics bascd on continuous heating diagram (CHT andcontinuous cooling diagram (CCT. The stresses generated during hardening were assumed to rcsult from ~hermal load. stntcturaI plasticdeformations and transformation plasricity. Thc hardened material was assumed to be elastic-plastic, and in ordcr to mark plastic strains the non-isothermal plastic law of flow with the isotropic hardening and condition plasticity of Huber-Misses were used. TherrnophysicaI values of mechanical phenomena dependent on bo~hth e phase composition and temperature. In the numerical example thc simulated estimation of the phasc Fraction and strcss distributions in the hardened axisimmetrical elemcnt was performed.

  17. Cold hardening and dehardening in Salix

    Energy Technology Data Exchange (ETDEWEB)

    Lennartsson, Mattias [Swedish Univ. of Agricultural Sciences, Umeaa (Sweden). Dept. of Forest Genetics and Plant Physiology

    2003-07-01

    The variation in cold hardiness in Salix in the autumn was investigated using clones of different geographic origins. In late growing season, the variation was small and inversely related to a phenotypic variation in potential growth rate. When growth had stopped in response to the reduction in daylength, however, large differences in cold hardiness developed. Northern/continental clones started cold hardening up to two months earlier and showed up to three times higher inherent rates of cold hardening than the southern/maritime ones. The two components of cold hardening, the timing of onset and the inherent rate, seemed to be separately inherited traits, as judged from analyses of the prodigy of a crossing between an early-and-rapidly hardening clone and a late-and-slowly hardening one. This suggests that cold hardiness can be improved without adversely affecting growth by selecting for a late onset of cold hardening combined with a rapid rate. Also, in the early stages, cold hardening was more sensitive to low, non-freezing temperatures in the southern/maritime clones than in the northern/continental ones. Cold hardening of stems in the autumn could be monitored from the accumulation of sugars, most predominantly sucrose, raffinose and stachyose. The accumulation of sucrose started already with the cessation of growth, whilst the accumulation of raffinose and stachyose started later and was stimulated by cool temperatures. Multivariate models using sugar data could explain 76% of the variation in cold hardiness in the early stages of hardening. Changes in levels of sugars and other compounds during cold hardening could be assessed non-intrusively from the visible and infrared reflectance spectra of stems. Multivariate models using spectral data could predict up to 96% of the variation in cold hardiness. This technique is expected to greatly facilitate breeding for improved cold hardiness by allowing rapid screening of large populations. The variation in cold

  18. Influences of Steelmaking Slags on Hydration and Hardening of Concretes

    Science.gov (United States)

    Kirsanova, A. A.; Dildin, A. N.; Maksimov, S. P.

    2017-11-01

    It is shown that the slag of metallurgical production can be used in the construction industry as an active mineral additive for concrete. This approach allows us to solve environmental problems and reduce costs for the production of binder and concrete simultaneously. Most often slag is used in the form of a filler, an active mineral additive or as a part of a binder for artificial conglomerates. The introduction of slag allows one to notice a part of the cement, to obtain concretes that are more resistant to the impact of aggressive sulfate media. The paper shows the possibility of using recycled steel-smelting slags in the construction industry for the production of cement. An assessment was made of their effect on the hydration of the cement stone and hardening of the concrete together with the plasticizer under normal conditions. In the process of work, we used the slag of the Zlatoust Electrometallurgical Factory. Possible limitations of the content of steel-slag slag in concrete because of the possible presence of harmful impurities are shown. It is necessary to enter slag in conjunction with superplasticizers to reduce the flow of water mixing. Slags can be used as a hardening accelerator for cement concrete as they allow one to increase the degree of cement hydration and concrete strength. It is shown that slags can be used to produce fast-hardening concretes and their comparative characteristics with other active mineral additives are given.

  19. The production of HTR-fuel kernels by microwave hardening of aqueous metal-salt-resin droplets

    International Nuclear Information System (INIS)

    Knotik, K.; Leichter, P.

    1981-04-01

    The construction and function of the microwave equipment for the hardening of free falling salt-resin-droplets, the preparation of solutions, their treatment and conditioning of the hardening process, the appearance and properties of the hardened ''green'' kernels and the transformation of ''green'' kernels of HTR-fuel kernels, i.e. sintered UO 2 -particles are described. With a suitable microwave equipment it is possible to harden aqueous droplets containing metal-salts (e.g. uranylnitrate), resorcinol and formaldehyde. The hardening occurs while the mentioned droplets are falling under gravity. These particles are suitable for the production of HTR-fuel kernels, e.g. high density UO 2 -particles. The entire process has the advantage of minimising the process specific waste. (author)

  20. Improving precipitation hardening behavior of Mg−Zn based alloys with Ce−Ca microalloying additions

    International Nuclear Information System (INIS)

    Langelier, B.; Korinek, A.; Donnadieu, P.; Esmaeili, S.

    2016-01-01

    The precipitation hardening behavior of newly developed Mg−Zn−Ca−Ce alloys, with modified texture and improved ductility, is studied to delineate the microstructural characteristics that lead to effective hardening upon ageing treatments. Advanced electron microscopy and atom probe techniques are used to analyze the structural characteristics in relevance to the hardening potential. It has been found that the formation of a new basal precipitate phase, which evolves from a single atomic layer GP zone, and is finely distributed in both under-aged and peak-aged microstructures, has a significant impact in the improvement of the hardening response compared with the base Mg−Zn alloys. It has also been found that the β′ 1 rod precipitates, commonly formed during ageing treatments of Mg−Zn alloys, have their size and distribution significantly refined in the Ca−Ce containing alloys. The role of alloy chemistry in the formation of the fine basal plate GP zones and the refinement in β′ 1 precipitation and their relationships to the hardening behavior are discussed. It is proposed that Ca microalloying governs the formation of the GP zones and the enhancement of hardening, particularly in the under-aged conditions, but that this is aided by a beneficial effect from Ce. - Highlights: • Ce−Ca microalloying additions improve hardening in Mg−Zn, over Ce or Ca alone. • Improved hardening is due to refined β′ 1 rods, and fine basal plate precipitates. • Atom probe tomography identifies Ca in both β′ 1 and the fine basal plates. • The fine basal plates originate as ordered monolayer GP zones with 1:1 Zn:Ca (at.%). • With ageing GP zones become more Zn-rich and transform to the fine basal plates.

  1. An Anisotropic Hardening Model for Springback Prediction

    International Nuclear Information System (INIS)

    Zeng, Danielle; Xia, Z. Cedric

    2005-01-01

    As more Advanced High-Strength Steels (AHSS) are heavily used for automotive body structures and closures panels, accurate springback prediction for these components becomes more challenging because of their rapid hardening characteristics and ability to sustain even higher stresses. In this paper, a modified Mroz hardening model is proposed to capture realistic Bauschinger effect at reverse loading, such as when material passes through die radii or drawbead during sheet metal forming process. This model accounts for material anisotropic yield surface and nonlinear isotropic/kinematic hardening behavior. Material tension/compression test data are used to accurately represent Bauschinger effect. The effectiveness of the model is demonstrated by comparison of numerical and experimental springback results for a DP600 straight U-channel test

  2. Hardening by annealing: insights from different alloys

    International Nuclear Information System (INIS)

    Renk, O; Pippan, R; Hohenwarter, A; Schuh, B; Li, J H

    2015-01-01

    In contrast to the general notion about the annealing behavior of coarse grained materials, hardening phenomena in nanocrystalline materials can occur. Although the phenomena have already been recognized several years ago, the mechanisms behind are still controversially discussed. For example, the influence of solutes segregated to grain boundaries on the strengthening mechanism is unclear. We present a combination of atom probe tomography and mechanical data to reveal the role of segregations to the strengthening. The results show that despite large modifications of the boundary chemistry the mechanical behavior remains widely unaffected. Additionally, it will be shown that hardening upon annealing can only occur below a material-specific grain size threshold value. (paper)

  3. Design considerations for a radiation hardened nonvolatile memory

    International Nuclear Information System (INIS)

    Murray, J.R.

    1993-01-01

    Sub-optimal design practices can reduce the radiation hardness of a circuit even though it is fabricated in a radiation hardened process. This is especially true for a nonvolatile memory, as compared to a standard digital circuit, where high voltages and unusual bias conditions are required. This paper will discuss the design technique's used in the development of a 64K EEPROM (Electrically Erasable Programmable Read Only Memory) to maximize radiation hardness. The circuit radiation test results will be reviewed in order to provide validation of the techniques

  4. Rationale simplified hardening training and recreational complexes future teachers

    Directory of Open Access Journals (Sweden)

    Verbludov I.B.

    2010-02-01

    Full Text Available Distribution in the modern world epidemiological diseases are influenza and acute respiratory viral infections requires a search for simplified, effective preventive means. The main direction of prevention of these diseases is to strengthen and enhance the activities of the immune system. Strengthening the protective systems of the body is directly related to the constant holding of different types of hardening. This study illustrates the possibility of using quenching air and water in the independent exercise training and recreational facilities in all conditions of students.

  5. Superficial hardened layer of cut surface by turning

    Directory of Open Access Journals (Sweden)

    Croitoru Sorin Mihai

    2017-01-01

    Full Text Available One of research methods in metal cutting process is to measure hardness in the contact zone between cutting tool and workpiece. The objective of the performed research was to determine thickness and hardness of the superficial layer of cut surface due to cutting process, both orthogonal and complex cutting. The most important finding was that thickness of the superficial hardened layer is very thin under considered conditions, less than 0.01 … 0.02 mm. This research should be continued.

  6. HTPro: Low-temperature Surface Hardening of Stainless Steel

    DEFF Research Database (Denmark)

    Christiansen, Thomas Lundin; Somers, Marcel A. J.

    2013-01-01

    Low-temperature surface hardening of stainless steel provides the required performance properties without affecting corrosion resistance.......Low-temperature surface hardening of stainless steel provides the required performance properties without affecting corrosion resistance....

  7. A case hardened component of titanium

    DEFF Research Database (Denmark)

    2017-01-01

    The present invention relates to a case hardened component of a titanium alloy, the component having a diffusion zone of a thickness of at least 50 μιτι, as calculated from the surface of the component, the diffusion zone comprising oxygen and carbon in solid solution and having a distinct phase...

  8. Mesoscopic model for ferromagnets with isotropic hardening

    Czech Academy of Sciences Publication Activity Database

    Roubíček, Tomáš; Kružík, Martin

    2005-01-01

    Roč. 56, č. 1 (2005), s. 107-135 ISSN 0044-2275 R&D Projects: GA AV ČR IAA1075005 Institutional research plan: CEZ:AV0Z10750506 Keywords : variational inequalities * ferromagnetism * hysteresis, hardening Subject RIV: BA - General Mathematics Impact factor: 0.455, year: 2005

  9. Instabilities in power law gradient hardening materials

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Tvergaard, Viggo

    2005-01-01

    Tension and compression instabilities are investigated for specimens with dimensions in the micron range. A finite strain generalization of a higher order strain gradient plasticity theory is implemented in a finite element scheme capable of modeling power law hardening materials. Effects...

  10. Radiation dose effects, hardening of electronic components

    International Nuclear Information System (INIS)

    Dupont-Nivet, E.

    1991-01-01

    This course reviews the mechanism of interaction between ionizing radiation and a silicon oxide type dielectric, in particular the effect of electron-hole pairs creation in the material. Then effects of cumulated dose on electronic components and especially in MOS technology are examined. Finally methods hardening of these components are exposed. 93 refs

  11. CASE-HARDENING OF STAINLESS STEEL

    DEFF Research Database (Denmark)

    2004-01-01

    The invention relates to case-hardening of a stainless steel article by means of gas including carbon and/or nitrogen, whereby carbon and/or nitrogen atoms diffuse through the surface into the article. The method includes activating the surface of the article, applying a top layer on the activated...

  12. Effect of strain rate on bake hardening response of BH220 steel

    Directory of Open Access Journals (Sweden)

    Das Anindya

    2015-01-01

    Full Text Available This study aims at understanding the bake hardening ability of ultra low carbon BH220 steel at different strain rates. The as-received material has been pre-strained to four different levels and then deformed in tension under (a as pre-strained state and (b after baking at 170 ∘C for 20 minutes, at three different strain rates of 0.001, 0.1 and 100/s. In both the conditions, yield stress increased with pre-strain and strain rate, but bake hardening ability was found to decrease when strain rate was increased. The strain rate sensitivity of the material was also found to decrease with bake hardening. Generation of dislocation forests and their subsequent immobility during baking treatment enables them to act as long range obstacles during further deformation. At higher strain rates, less amount of dislocations are produced which can interact with themselves and produce hardening, because of which bake hardening ability and the strain rate drops. A dislocation based strengthening model, as proposed by Larour et al. 2011 [7], was used to predict the yield stress values obtained at different conditions. The equation produced excellent co-relation with the experimental data.

  13. idRHa+ProMod - Rail Hardening Control System

    International Nuclear Information System (INIS)

    Ferro, L

    2016-01-01

    idRHa+ProMod is the process control system developed by Primetals Technologies to foresee the thermo-mechanical evolution and micro-structural composition of rail steels subjected to slack quenching into idRHa+ Rail Hardening equipments in a simulation environment. This tool can be used both off-line or in-line, giving the user the chance to test and study the best cooling strategies or letting the automatic control system free to adjust the proper cooling recipe. Optimization criteria have been tailored in order to determine the best cooling conditions according to the metallurgical requirements imposed by the main rail standards and also taking into account the elastoplastic bending phenomena occurring during all stages of the head hardening process. The computational core of idRHa+ProMod is a thermal finite element procedure coupled with special algorithms developed to work out the main thermo-physical properties of steel, to predict the non-isothermal austenite decomposition into all the relevant phases and subsequently to evaluate the amount of latent heat of transformation released, the compound thermal expansion coefficient and the amount of plastic deformation in the material. Air mist and air blades boundary conditions have been carefully investigated by means of pilot plant tests aimed to study the jet impingement on rail surfaces and the cooling efficiency at all working conditions. Heat transfer coefficients have been further checked and adjusted directly on field during commissioning. idRHa+ is a trademark of Primetals Technologies Italy Srl (paper)

  14. idRHa+ProMod - Rail Hardening Control System

    Science.gov (United States)

    Ferro, L.

    2016-03-01

    idRHa+ProMod is the process control system developed by Primetals Technologies to foresee the thermo-mechanical evolution and micro-structural composition of rail steels subjected to slack quenching into idRHa+ Rail Hardening equipments in a simulation environment. This tool can be used both off-line or in-line, giving the user the chance to test and study the best cooling strategies or letting the automatic control system free to adjust the proper cooling recipe. Optimization criteria have been tailored in order to determine the best cooling conditions according to the metallurgical requirements imposed by the main rail standards and also taking into account the elastoplastic bending phenomena occurring during all stages of the head hardening process. The computational core of idRHa+ProMod is a thermal finite element procedure coupled with special algorithms developed to work out the main thermo-physical properties of steel, to predict the non-isothermal austenite decomposition into all the relevant phases and subsequently to evaluate the amount of latent heat of transformation released, the compound thermal expansion coefficient and the amount of plastic deformation in the material. Air mist and air blades boundary conditions have been carefully investigated by means of pilot plant tests aimed to study the jet impingement on rail surfaces and the cooling efficiency at all working conditions. Heat transfer coefficients have been further checked and adjusted directly on field during commissioning. idRHa+ is a trademark of Primetals Technologies Italy Srl

  15. Radiation hardened COTS-based 32-bit microprocessor

    International Nuclear Information System (INIS)

    Haddad, N.; Brown, R.; Cronauer, T.; Phan, H.

    1999-01-01

    A high performance radiation hardened 32-bit RISC microprocessor based upon a commercial single chip CPU has been developed. This paper presents the features of radiation hardened microprocessor, the methods used to radiation harden this device, the results of radiation testing, and shows that the RAD6000 is well-suited for the vast majority of space applications. (authors)

  16. Short-term exposure to atmospheric ammonia does not affect frost hardening of needles from three- and five-year-old Scots pine trees

    NARCIS (Netherlands)

    Clement, J.M A M; van Hasselt, P.R; van Eerden, L.J.M.; Dueck, T.A.

    The effect of atmospheric ammonia on frost hardening of needles from 3- and 5-year-old Scots pine trees was investigated. Trees were exposed to various concentrations of NH(3) during different hardening stages under laboratory conditions and in experiments with open-top chambers under a natural

  17. Metallographic examination of hardened layers after surface treatments by highly concentrated plasma jet

    Directory of Open Access Journals (Sweden)

    Сергій Савелійович Самотугін

    2017-07-01

    Full Text Available The microstructure of carbon and alloy steels with various carbon contents before and after the gradient hardening by means of highly concentrated plasma jet have been investigated. It is shown that the resulting structure after the surface hardening has a substantially smaller grain size as compared to the bulk hardening. The steels with different carbon content, that is hypoeutectic steels 45 and 50HN, eutectic steels – M76, U8, hypereutectoid steels – 90HF, U10 have been researched. Processing was carried out under the optimal conditions to ensure the highest hardness of the surface without melting. Metalgraphical studies were carried out using optical and scanning electron microscopes. High-dispersed martensite is the main structural component for hypoeutectic steels. Despite the fact that the heating temperature and the cooling rate in different parts of the plasma exposure zone differ greatly, the structure of the tempered zone is uniform by both the degree of dispersion and by the values of hardness. Plasma treatment of eutectic steels results in fine-grained structure of martensite of mainly lamellar morphology. High-dispersed martensite with microparticles of secondary carbides is characteristic of the hardened zones for hypereutectic steels. But austenite grains do not grow at heating as it usually happens in bulk hardening. The structure of the transition zone corresponds to part-hardened steels. So excess ferrite as well as martensite retains in hypoeutectic steels while excess cementite retains in hypereutectic steels. Eutectic steels are free from the intercritical interval, and the transition zone does not practically develop, there being a very sharp boundary between the zone of full hardening and the parent metal. Due to this structure of the plasma hardening zone of the surface layer there arises 3,5...4,5-fold increase in the hardness of the steel as compared with the normalized condition. This is due to the increase in

  18. Induction hardening treatment and simulation for a grey cast iron used in engine cylinder liners

    Science.gov (United States)

    Castellanos-Leal, E. L.; Miranda, D. A.; Coy, A. E.; Barrero, J. G.; González, J. A.; Vesga Rueda, O. P.

    2017-01-01

    In this research, a technical study of induction hardening in a grey cast iron used in engine cylinder liners manufactured by LAVCO Ltda., a Colombian foundry company, was carried out. Metallurgical parameters such as austenitization temperature, cooling rate, and quenching severity were determined. These factors are exclusively dependent on chemical composition and initial microstructure of grey cast iron. Simulations of induction heating through finite elements method were performed and, the most appropriate experimental conditions to achieve the critical transformation temperature was evaluated to reach a proper surface hardening on the piece. Preliminary results revealed an excellent approximation between simulation and heating test performed with a full bridge inverter voltage adapted with local technology.

  19. Experimental study and theoretical simulation of the cross hardening effect in shape memory alloys

    Science.gov (United States)

    Movchan, A. A.; Sil'chenko, A. L.; Kazarina, S. A.

    2017-10-01

    The shapes and the relative position of martensitic inelasticity and forward transformation diagrams are experimentally studied. The strain dependences of the stress in loading under martensitic inelasticity conditions after an experiment on the accumulation of the forward transformation-induced strain at a constant or variable stress are investigated on titanium nickelide samples. It is found that the hardening of the martensite part of the representative volume of a shape memory alloy (titanium nickelide) after forward transformation under a nonmonotonically changing stress can be nonuniform. The cross hardening phenomenon is theoretically described in terms of the model of nonlinear deformation of a shape memory alloy during phase and structural transformations.

  20. Temperature Effects on the Tensile Properties of Precipitation-Hardened Al-Mg-Cu-Si Alloys

    Directory of Open Access Journals (Sweden)

    J.B. Ferguson

    2016-02-01

    Full Text Available Because the mechanical performance of precipitation-hardened alloys can be significantly altered with temperature changes, understanding and predicting the effects of temperatures on various mechanical properties for these alloys are important. In the present work, an analytical model has been developed to predict the elastic modulus, the yield stress, the failure stress, and the failure strain taking into consideration the effect of temperatures for precipitation-hardenable Al-Mg-Cu-Si Alloys (Al-A319 alloys. In addition, other important mechanical properties of Al-A319 alloys including the strain hardening exponent, the strength coefficient, and the ductility parameter can be estimated using the current model. It is demonstrated that the prediction results based on the proposed model are in good agreement with those obtained experimentally in Al-A319 alloys in the as-cast condition and after W and T7 heat treatments.

  1. Densification and strain hardening of a metallic glass under tension at room temperature.

    Science.gov (United States)

    Wang, Z T; Pan, J; Li, Y; Schuh, C A

    2013-09-27

    The deformation of metallic glasses involves two competing processes: a disordering process involving dilatation, free volume accumulation, and softening, and a relaxation process involving diffusional ordering and densification. For metallic glasses at room temperature and under uniaxial loading, disordering usually dominates, and the glass can fail catastrophically as the softening process runs away in a localized mode. Here we demonstrate conditions where the opposite, unexpected, situation occurs: the densifying process dominates, resulting in stable plastic deformation and work hardening at room temperature. We report densification and hardening during deformation in a Zr-based glass under multiaxial loading, in a notched tensile geometry. The effect is driven by stress-enhanced diffusional relaxation, and is attended by a reduction in exothermic heat and hardening signatures similar to those observed in the classical thermal relaxation of glasses. The result is significant, stable, plastic, extensional flow in metallic glasses, which suggest a possibility of designing tough glasses based on their flow properties.

  2. Cyclic hardening in bundled actin networks.

    Science.gov (United States)

    Schmoller, K M; Fernández, P; Arevalo, R C; Blair, D L; Bausch, A R

    2010-01-01

    Nonlinear deformations can irreversibly alter the mechanical properties of materials. Most soft materials, such as rubber and living tissues, display pronounced softening when cyclically deformed. Here we show that, in contrast, reconstituted networks of crosslinked, bundled actin filaments harden when subject to cyclical shear. As a consequence, they exhibit a mechano-memory where a significant stress barrier is generated at the maximum of the cyclic shear strain. This unique response is crucially determined by the network architecture: at lower crosslinker concentrations networks do not harden, but soften showing the classic Mullins effect known from rubber-like materials. By simultaneously performing macrorheology and confocal microscopy, we show that cyclic shearing results in structural reorganization of the network constituents such that the maximum applied strain is encoded into the network architecture.

  3. Nitrogen nutrition and drought hardening exert opposite effects on the stress tolerance of Pinus pinea L. seedlings.

    Science.gov (United States)

    Villar-Salvador, Pedro; Peñuelas, Juan L; Jacobs, Douglass F

    2013-02-01

    Functional attributes determine the survival and growth of planted seedlings in reforestation projects. Nitrogen (N) and water are important resources in the cultivation of forest species, which have a strong effect on plant functional traits. We analyzed the influence of N nutrition on drought acclimation of Pinus pinea L. seedlings. Specifically, we addressed if high N fertilization reduces drought and frost tolerance of seedlings and whether drought hardening reverses the effect of high N fertilization on stress tolerance. Seedlings were grown under two N fertilization regimes (6 and 100 mg N per plant) and subjected to three drought-hardening levels (well-watered, moderate and strong hardening). Water relations, gas exchange, frost damage, N concentration and growth at the end of the drought-hardening period, and survival and growth of seedlings under controlled xeric and mesic outplanting conditions were measured. Relative to low-N plants, high-N plants were larger, had higher stomatal conductance (27%), residual transpiration (11%) and new root growth capacity and closed stomata at higher water potential. However, high N fertilization also increased frost damage (24%) and decreased plasmalemma stability to dehydration (9%). Drought hardening reversed to a great extent the reduction in stress tolerance caused by high N fertilization as it decreased frost damage, stomatal conductance and residual transpiration by 21, 31 and 24%, respectively, and increased plasmalemma stability to dehydration (8%). Drought hardening increased tissue non-structural carbohydrates and N concentration, especially in high-fertilized plants. Frost damage was positively related to the stability of plasmalemma to dehydration (r = 0.92) and both traits were negatively related to the concentration of reducing soluble sugars. No differences existed between moderate and strong drought-hardening treatments. Neither N nutrition nor drought hardening had any clear effect on seedling

  4. Finite Element Model of Gear Induction Hardening

    OpenAIRE

    Hodek, J; Zemko, M; Shykula, P

    2015-01-01

    International audience; This paper presents a finite element model of a gear induction hardening process. The gear was surface-heated by an induction coil and quickly cooled by spraying water. The finite element model was developed as a three-dimensional model. The electromagnetic field, temperature field, stress distribution and microstructure distribution were examined. Temperature and microstructural characteristics were measured and used. The gear material data was obtained in part by mea...

  5. Metallurgical Examination of Face Hardened Armor Plate

    Science.gov (United States)

    1944-02-29

    2 SAMPLE 4 FIBRE TEST STEEL QUALITY TESI FRACTURES OF FACE HAqDENED ARMIOR 25 JAN 1944 W’sN.710-2268 FIGURE *rfMO Reproduced FromBest Available Clop’ý...5 6 7 8910 12 14 16182024 40 DISTANCE FROM WATER COOLED END OF STANDARiW2 HARDENABILITY BAR - SIXTEENTHS PLATE HEAT OUENCH NO. NO. C N1SI 1 P NIOR 4

  6. Novel circuits for radiation hardened memories

    International Nuclear Information System (INIS)

    Haraszti, T.P.; Mento, R.P.; Moyer, N.E.; Grant, W.M.

    1992-01-01

    This paper reports on implementation of large storage semiconductor memories which combine radiation hardness with high packing density, operational speed, and low power dissipation and require both hardened circuit and hardened process technologies. Novel circuits, including orthogonal shuffle type of write-read arrays, error correction by weighted bidirectional codes and associative iterative repair circuits, are proposed for significant improvements of SRAMs' immunity against the effects of total dose and cosmic particle impacts. The implementation of the proposed circuit resulted in fault-tolerant 40-Mbit and 10-Mbit monolithic memories featuring a data rate of 120 MHz and power dissipation of 880 mW. These experimental serial-parallel memories were fabricated with a nonhardened standard CMOS processing technology, yet provided a total dose hardness of 1 Mrad and a projected SEU rate of 1 x 10 - 12 error/bit/day. Using radiation hardened processing improvements by factors of 10 to 100 are predicted in both total dose hardness and SEU rate

  7. Empirical beam hardening correction (EBHC) for CT

    Energy Technology Data Exchange (ETDEWEB)

    Kyriakou, Yiannis; Meyer, Esther; Prell, Daniel; Kachelriess, Marc [Institute of Medical Physics, University of Erlangen-Nuernberg, 91052 Erlangen (Germany)

    2010-10-15

    Purpose: Due to x-ray beam polychromaticity and scattered radiation, attenuation measurements tend to be underestimated. Cupping and beam hardening artifacts become apparent in the reconstructed CT images. If only one material such as water, for example, is present, these artifacts can be reduced by precorrecting the rawdata. Higher order beam hardening artifacts, as they result when a mixture of materials such as water and bone, or water and bone and iodine is present, require an iterative beam hardening correction where the image is segmented into different materials and those are forward projected to obtain new rawdata. Typically, the forward projection must correctly model the beam polychromaticity and account for all physical effects, including the energy dependence of the assumed materials in the patient, the detector response, and others. We propose a new algorithm that does not require any knowledge about spectra or attenuation coefficients and that does not need to be calibrated. The proposed method corrects beam hardening in single energy CT data. Methods: The only a priori knowledge entering EBHC is the segmentation of the object into different materials. Materials other than water are segmented from the original image, e.g., by using simple thresholding. Then, a (monochromatic) forward projection of these other materials is performed. The measured rawdata and the forward projected material-specific rawdata are monomially combined (e.g., multiplied or squared) and reconstructed to yield a set of correction volumes. These are then linearly combined and added to the original volume. The combination weights are determined to maximize the flatness of the new and corrected volume. EBHC is evaluated using data acquired with a modern cone-beam dual-source spiral CT scanner (Somatom Definition Flash, Siemens Healthcare, Forchheim, Germany), with a modern dual-source micro-CT scanner (TomoScope Synergy Twin, CT Imaging GmbH, Erlangen, Germany), and with a modern

  8. Empirical beam hardening correction (EBHC) for CT

    International Nuclear Information System (INIS)

    Kyriakou, Yiannis; Meyer, Esther; Prell, Daniel; Kachelriess, Marc

    2010-01-01

    Purpose: Due to x-ray beam polychromaticity and scattered radiation, attenuation measurements tend to be underestimated. Cupping and beam hardening artifacts become apparent in the reconstructed CT images. If only one material such as water, for example, is present, these artifacts can be reduced by precorrecting the rawdata. Higher order beam hardening artifacts, as they result when a mixture of materials such as water and bone, or water and bone and iodine is present, require an iterative beam hardening correction where the image is segmented into different materials and those are forward projected to obtain new rawdata. Typically, the forward projection must correctly model the beam polychromaticity and account for all physical effects, including the energy dependence of the assumed materials in the patient, the detector response, and others. We propose a new algorithm that does not require any knowledge about spectra or attenuation coefficients and that does not need to be calibrated. The proposed method corrects beam hardening in single energy CT data. Methods: The only a priori knowledge entering EBHC is the segmentation of the object into different materials. Materials other than water are segmented from the original image, e.g., by using simple thresholding. Then, a (monochromatic) forward projection of these other materials is performed. The measured rawdata and the forward projected material-specific rawdata are monomially combined (e.g., multiplied or squared) and reconstructed to yield a set of correction volumes. These are then linearly combined and added to the original volume. The combination weights are determined to maximize the flatness of the new and corrected volume. EBHC is evaluated using data acquired with a modern cone-beam dual-source spiral CT scanner (Somatom Definition Flash, Siemens Healthcare, Forchheim, Germany), with a modern dual-source micro-CT scanner (TomoScope Synergy Twin, CT Imaging GmbH, Erlangen, Germany), and with a modern

  9. Fatigue hardening and softening studies on strain hardened 18-8 austenitic stainless steel

    International Nuclear Information System (INIS)

    Ramakrishna Prasad, C.; Vasudevan, R.

    1976-01-01

    Metals when subjected to fatigue harden or soften depending on their previous mechanical history. Annealed or mildly cold worked metals are known to harden while severely cold worked metals soften when subjected to fatigue loading. In the present work samples of austenitic 18-8 steel cold worked to 11% and 22% reduction in area were mounted in a vertical pulsator and fatigued in axial tension-compression. Clear cut effects were produced and it was noticed that these depended on the extent of cold work, the amplitude as well as the number of cycles of fatigue and mean stress if any. (orig.) [de

  10. BUSFET -- A radiation-hardened SOI transistor

    International Nuclear Information System (INIS)

    Schwank, J.R.; Shaneyfelt, M.R.; Draper, B.L.; Dodd, P.E.

    1999-01-01

    The total-dose hardness of SOI technology is limited by radiation-induced charge trapping in gate, field, and SOI buried oxides. Charge trapping in the buried oxide can lead to back-channel leakage and makes hardening SOI transistors more challenging than hardening bulk-silicon transistors. Two avenues for hardening the back-channel are (1) to use specially prepared SOI buried oxides that reduce the net amount of trapped positive charge or (2) to design transistors that are less sensitive to the effects of trapped charge in the buried oxide. In this work, the authors propose a partially-depleted SOI transistor structure for mitigating the effects of trapped charge in the buried oxide on radiation hardness. They call this structure the BUSFET--Body Under Source FET. The BUSFET utilizes a shallow source and a deep drain. As a result, the silicon depletion region at the back channel caused by radiation-induced charge trapping in the buried oxide does not form a conducting path between source and drain. Thus, the BUSFET structure design can significantly reduce radiation-induced back-channel leakage without using specially prepared buried oxides. Total dose hardness is achieved without degrading the intrinsic SEU or dose rate hardness of SOI technology. The effectiveness of the BUSFET structure for reducing total-dose back-channel leakage depends on several variables, including the top silicon film thickness and doping concentration, and the depth of the source. 3-D simulations show that for a body doping concentration of 10 18 cm -3 , a drain bias of 3 V, and a source depth of 90 nm, a silicon film thickness of 180 nm is sufficient to almost completely eliminate radiation-induced back-channel leakage. However, for a doping concentration of 3 x 10 17 cm -3 , a thicker silicon film (300 nm) must be used

  11. A Radiation Hardened Spacecraft Mass Memory System

    Science.gov (United States)

    Dennehy, W. J.; Lawton, B.; Stufflebeam, J.

    The functional design of a Radiation Hardened Spacecraft Mass Memory System (RH/SMMS) is described. This system is configured around a 1 megabit memory device and incorporates various system and circuit design features to achieve radiation hardness. The system is modular and storage capacities of 16 to 32 megabits are achievable within modest size, weight, and power constraints. Estimates of physical characteristics (size, weight, and power) are presented for a 16 Mbit system. The RH/SMMS is organized in a disk-like architecture and offers the spacecraft designer several unique benefits such as: reduced software cost, increased autonomy and survivability, increased functionality and increased fault tolerance.

  12. Radiation-hardened nonvolatile MNOS RAM

    International Nuclear Information System (INIS)

    Wrobel, T.F.; Dodson, W.H.; Hash, G.L.; Jones, R.V.; Nasby, R.D.; Olson, R.J.

    1983-01-01

    A radiation hardened nonvolatile MNOS RAM is being developed at Sandia National Laboratories. The memory organization is 128 x 8 bits and utilizes two p-channel MNOS transistors per memory cell. The peripheral circuitry is constructed with CMOS metal gate and is processed with standard Sandia rad-hard processing techniques. The devices have memory retention after a dose-rate exposure of 1E12 rad(Si)/s, are functional after total dose exposure of 1E6 rad(Si), and are dose-rate upset resistant to levels of 7E8 rad(Si)/s

  13. Coating compositions hardenable by ionization beams

    International Nuclear Information System (INIS)

    Chaudhari, D.; Haering, E.; Dobbelstein, A.; Hoselmann, W.

    1976-01-01

    Coating compositions hardenable by ionizing radiation are described which contain as binding agents a mixture of at least 1 unsaturated olefin compound containing urethane groups, and at least 1 further unsaturated olefin compound that may be copolymerized. The unsaturated olefin compound containing the urethane groups is a reaction product of a compound containing carboxylic acid groups and a compound containing at least 1 isocyanate group where the mixture of the two olefins may contain conventional additives of the lacquer industry. 6 claims, no drawings

  14. Thermomechanical and Heat Hardening of Building Steels

    Science.gov (United States)

    Odesskii, P. D.; Rudchenko, A. V.; Shabalov, I. P.

    2005-03-01

    Hardening treatment of steels used in welded metal structures like steelwork of industrial and civil buildings, towers, poles, reservoirs, railway bridge girders, cranes, construction machines, truck bodies, etc. is considered. The structures mentioned are produced from rolled stock supplied by metallurgy in an annual amount of tens of million of tons. In the first turn these are plates, shapes, rolled bars and sections, and pipes with different wall thickness and cross section. A classification of steels for metallic structures with respect to chemical composition and microstructure is presented.

  15. Configurable Radiation Hardened High Speed Isolated Interface ASIC Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NVE Corporation will design and build an innovative, low cost, flexible, configurable, radiation hardened, galvanically isolated, interface ASIC chip set that will...

  16. Configurable Radiation Hardened High Speed Isolated Interface ASIC, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — NVE Corporation will design and build an innovative, low cost, flexible, configurable, radiation hardened, galvanically isolated, interface ASIC chip set that will...

  17. Radiation-tolerant, sidewall-hardened SOI/MOS transistors

    International Nuclear Information System (INIS)

    Tsao, S.S.; Fleetwood, D.M.; Weaver, H.T.; Pfeiffer, L.; Celler, G.K.

    1987-01-01

    Total dose radiation effects were measured for sidewall-hardened n-channel SOI/MOS transistors, fabricated in zone-melt-recrystallized (ZMR) and oxygen-implanted (SIMOX) SOI materials. The authors compare the radiation responses of transistors with three types of sidewall or edge configurations: island transistors with passivated edges, island transistors without passivated edges, and edgeless (enclosed-gate) transistors. Data from these three test devices allow clear separation of front-, back-, and edge-channel conduction. Passivated edge channels were hard to Co-60 doses in excess of 24 Mrad(Si). The overall hardness of the passivated-edge transistors is limited only by the radiation-induced threshold voltage shifts (about -1 V at 1.0 Mrad) of the top channel. No significant differences in total-dose response of ZMR and SIMOX devices were observed under the radiation conditions employed

  18. Strain path and work-hardening behavior of brass

    Energy Technology Data Exchange (ETDEWEB)

    Sakharova, N.A.; Fernandes, J.V. [CEMUC, Department of Mechanical Engineering, University of Coimbra, Rua Luis Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra (Portugal); Vieira, M.F. [CEMUC, Department of Metallurgical and Materials Engineering, Faculty of Engineering of University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal)], E-mail: mvieira@fe.up.pt

    2009-05-15

    Plastic straining in metal forming usually includes changes of strain path, which are frequently not taken into account in the analysis of forming processes. Moreover, strain path change can significantly affect the mechanical behavior and microstructural evolution of the material. For this reason, a combination of several simple loading test sequences is an effective way to investigate the dislocation microstructure of sheet metals under such forming conditions. Pure tension and rolling strain paths and rolling-tension strain path sequences were performed on brass sheets. A study of mechanical behavior and microstructural evolution during the simple and the complex strain paths was carried out, within a wide range of strain values. The appearance and development of deformation twinning was evident. It was shown that strain path change promotes the onset of premature twinning. The work-hardening behavior is discussed in terms of the twinning and dislocation microstructure evolution, as revealed by transmission electron microscopy.

  19. Condition For Strain-Hardening In Ecc Uniaxial Test Specimen

    DEFF Research Database (Denmark)

    Dick-Nielsen, Lars; Stang, Henrik; Poulsen, Peter Noe

    2006-01-01

    and infinite sheets under uniaxial tension. The crack is assumed to be cohesive and the cohesive law applied takes into account fiber as well as mortar properties. It is shown that the maximum crack opening observed during crack propagation in various test specimen geometries is small, 20 m and also small......This paper discusses the adequateness of the steady state flat crack criterion for crack propagation in Engineered Cementitious Composites. The investigation is performed by use of a semi-analytical model as well as a Finite Element Model. The simulations are for one crack propagating in finite...

  20. Hardness variability in commercial and hardened technologies

    Energy Technology Data Exchange (ETDEWEB)

    Shaneyfelt, M.R.; Winokur, P.S.; Meisenheimer, T.L.; Sexton, F.W.; Roeske, S.B.; Knoll, M.G.

    1994-03-01

    Over the past 10 years, there have been a number of advances in methods to assess and assure the radiation hardness of microelectronics in military and space applications. At the forefront of these is the Qualified Manufacturers List (QML) methodology, in which the hardness of product is ``built-in`` through statistical process control (SPC) of technology parameters relevant to the radiation response, test structure to integrated circuit (IC) correlations, and techniques for extrapolating laboratory test results to varying radiation scenarios. At the same time, there has been renewed interest in the use of commercial technology -- with its enhanced performance, reduced cost, and higher reliability -- in military and space systems. In this paper, we initially demonstrate the application of QML techniques to assure and control the radiation response of hardened technologies. Through several examples, we demonstrate intra-die, wafer-to-wafer, and lot-to-lot variations in a hardened technology. We observe 10 to 30% variations in key technology parameters that result from variability in geometry, process, and design layout. Radiation-induced degradation is seen to mirror preirradiation characteristics. We then evaluate commercial technologies and report considerably higher variability in radiation hardness, i.e., variations by a factor of two to five. This variability is shown to arise from a lack of control of technology parameters relevant to the radiation response, which a commercial manufacturer has no interest in controlling in a normal process flow.

  1. Hardened Client Platforms for Secure Internet Banking

    Science.gov (United States)

    Ronchi, C.; Zakhidov, S.

    We review the security of e-banking platforms with particular attention to the exploitable attack vectors of three main attack categories: Man-in-the-Middle, Man-in-the-PC and Man-in-the-Browser. It will be shown that the most serious threats come from combination attacks capable of hacking any transaction without the need to control the authentication process. Using this approach, the security of any authentication system can be bypassed, including those using SecureID Tokens, OTP Tokens, Biometric Sensors and Smart Cards. We will describe and compare two recently proposed e-banking platforms, the ZTIC and the USPD, both of which are based on the use of dedicated client devices, but with diverging approaches with respect to the need of hardening the Web client application. It will be shown that the use of a Hardened Browser (or H-Browser) component is critical to force attackers to employ complex and expensive techniques and to reduce the strength and variety of social engineering attacks down to physiological fraud levels.

  2. AtMyb7, a subgroup 4 R2R3 Myb, negatively regulates ABA-induced inhibition of seed germination by blocking the expression of the bZIP transcription factor ABI5

    KAUST Repository

    Kim, Junhyeok

    2014-08-27

    Various Myb proteins have been shown to play crucial roles in plants, including primary and secondary metabolism, determination of cell fate and identity, regulation of development and involvement in responses to biotic and abiotic stresses. The 126 R2R3 Myb proteins (with two Myb repeats) have been found in Arabidopsis; however, the functions of most of these proteins remain to be fully elucidated. In the present study, we characterized the function of AtMyb7 using molecular biological and genetic analyses. We used qRT-PCR to determine the levels of stress-response gene transcripts in wild-type and atmyb7 plants. We showed that ArabidopsisAtMyb7 plays a critical role in seed germination. Under abscisic acid (ABA) and high-salt stress conditions, atmyb7 plants showed a lower germination rate than did wild-type plants. Furthermore, AtMyb7 promoter:GUS seeds exhibited different expression patterns in response to variations in the seed imbibition period. AtMyb7 negatively controls the expression of the gene encoding bZIP transcription factor, ABI5, which is a key transcription factor in ABA signalling and serves as a crucial regulator of germination inhibition in Arabidopsis. © 2014 John Wiley & Sons Ltd.

  3. On use of radial evanescence remain term in kinematic hardening

    International Nuclear Information System (INIS)

    Geyer, P.

    1995-10-01

    A fine modelling of the material' behaviour can be necessary to study the mechanical strength of nuclear power plant' components under cyclic loads. Ratchetting is one of the last phenomena for which numerical models have to be improved. We discuss in this paper on use of radial evanescence remain term in kinematic hardening to improve the description of ratchetting in biaxial loading tests. It's well known that Chaboche elastoplastic model with two non linear kinematic hardening variables initially proposed by Armstrong and Frederick, usually over-predicts accumulation of ratchetting strain. Burlet and Cailletaud proposed in 1987 a non linear kinematic rule with a radial evanescence remain term. The two models lead to identical formulation for proportional loadings. In the case of a biaxial loading test (primary+secondary loading), Burlet and Cailletaud model leads to accommodation, when Chaboche one's leads to ratchetting with a constant increment of strain. So we can have an under-estimate with the first model and an over-estimate with the second. An easy method to improve the description of ratchetting is to combine the two kinematic rules. Such an idea is already used by Delobelle in his model. With analytical results in the case of tension-torsion tests, we show in a first part of the paper, the interest of radial evanescence remain term in the non linear kinematic rule to describe ratchetting: we give the conditions to get adaptation, accommodation or ratchetting and the value of the strain increment in the last case. In the second part of the paper, we propose to modify the elastoplastic Chaboche model by coupling the two types of hardening by means of two scalar parameters which can be identified independently on biaxial loading tests. Identification of these two parameters returns to speculate on the directions of strain in order to adjust the ratchetting to experimental observations. We use the experimental results on the austenitic steel 316L at room

  4. Metabolites and hormones are involved in the intraspecific variability of drought hardening in radiata pine.

    Science.gov (United States)

    De Diego, N; Saiz-Fernández, I; Rodríguez, J L; Pérez-Alfocea, P; Sampedro, M C; Barrio, R J; Lacuesta, M; Moncaleán, P

    2015-09-01

    Studies of metabolic and physiological bases of plant tolerance and hardening against drought are essential to improve genetic breeding programs, especially in productive species such as Pinus radiata. The exposure to different drought cycles is a highly effective tool that improves plant conditioning, but limited information is available about the mechanisms that modulate this process. To clarify this issue, six P. radiata breeds with well-known differences in drought tolerance were analyzed after two consecutive drought cycles. Survival rate, concentration of several metabolites such as free soluble amino acids and polyamines, and main plant hormones varied between them after drought hardening, while relative growth ratio and water potential at both predawn and dawn did not. Hardening induced a strong increase in total soluble amino acids in all breeds, accumulating mainly those implicated in the glutamate metabolism (GM), especially L-proline, in the most tolerant breeds. Other amino acids from GM such as γ-aminobutyric acid (GABA) and L-arginine (Arg) were also strongly increased. GABA pathway could improve the response against drought, whereas Arg acts as precursor for the synthesis of spermidine. This polyamine showed a positive relationship with the survival capacity, probably due to its role as antioxidant under stress conditions. Finally, drought hardening also induced changes in phytohormone content, showing each breed a different profile. Although all of them accumulated indole-3-acetic acid and jasmonic acid and reduced zeatin content in needles, significant differences were observed regarding abscisic acid, salicylic acid and mainly zeatin riboside. These results confirm that hardening is not only species-dependent but also an intraspecific processes controlled through metabolite changes. Copyright © 2015 Elsevier GmbH. All rights reserved.

  5. Fabrication of SiC hardened bodies with geopolymer binders using a warm press method

    Science.gov (United States)

    Hashimoto, Shinobu; Kubota, Kosuke; Ando, Kotaro; Tsutani, Masaki; Diko, Yusuke; Honda, Sawao; Iwamoto, Yuji

    2017-09-01

    Novel SiC hardened bodies with geopolymer binders using a warm press method were fabricated. In this study, two methods were tried. The first method used a conventional powder mixture consisted of SiC and geopolymer particles as starting materials. In the second method, SiC particles was first immersed in hydrochloric acid solution with 2.5 mol/L and then heated at 1200 °C for 6 h to form a reactive aluminosilicate layer at the surface of SiC particles. Subsequently, the resultant SiC particles mixed with a fixed amount of sodium hydroxide solution with various concentrations were put into a steel mold which was set in the warm press device. This second method was defined as a chemical assist processing. As this warm press condition, heating temperature was 130 °C and pressed at 240 MPa for 30 min simultaneously. When a powder mixture consisted of geopolymer and SiC particles was used, the compressive strength of the hardened bodies decreased with the amount of SiC particles. On the contrary, when the chemical assist processing method was selected, the compressive strength of the hardened bodies increased with the concentration of the sodium hydroxide solution. When the sodium hydroxide solution was 4 mol/L was used, the compressive strength of the hardened body reached to 170 MPa which was the maximum value in this study.

  6. Microstructural and Mechanical Study of Press Hardening of Thick Boron Steel Sheet

    Science.gov (United States)

    Pujante, J.; Garcia-Llamas, E.; Golling, S.; Casellas, D.

    2017-09-01

    Press hardening has become a staple in the production of automotive safety components, due to the combination of high mechanical properties and form complexity it offers. However, the use of press hardened components has not spread to the truck industry despite the advantages it confers, namely affordable weight reduction without the use of exotic materials, would be extremely attractive for this sector. The main reason for this is that application of press hardened components in trucks implies adapting the process to the manufacture of thick sheet metal. This introduces an additional layer of complexity, mainly due to the thermal gradients inside the material resulting in though-thickness differences in austenitization and cooling, potentially resulting in complex microstructure and gradient of mechanical properties. This work presents a preliminary study on the press hardening of thick boron steel sheet. First of all, the evolution of the sheet metal during austenitization is studied by means of dilatometry tests and by analysing the effect of furnace dwell time on grain size. Afterwards, material cooled using different cooling strategies, and therefore different effective cooling rates, is studied in terms of microstructure and mechanical properties. Initial results from finite element simulation are compared to experimental results, focusing on the phase composition in through thickness direction. Results show that industrial-equivalent cooling conditions do not lead to gradient microstructures, even in extreme scenarios involving asymmetrical cooling.

  7. The Surface Fatigue Life of Contour Induction Hardened AISI 1552 Gears

    Science.gov (United States)

    Townsend, Dennis P.; Turza, Alan; Chaplin, Mike

    1995-01-01

    Two groups of spur gears manufactured from two different materials and heat treatments were endurance tested for surface fatigue life. One group was manufactured from AISI 1552 and was finished ground to a 0.4 micron (16 micro-in.) rms surface finish and then dual frequency contour induction hardened. The second group was manufactured from CEVM AISI 9310 and was carburized, hardened, and ground to a 0.4 micron (16 micro-in.) rms surface finish. The gear pitch diameter was 8.89 cm (3.5 in.). Test conditions were a maximum Hertz stress of 1.71 GPa (248 ksi), a bulk gear temperature of approximately 350 K (170 F) and a speed of 10,000 rpm. The lubricant used for the tests was a synthetic paraffinic oil with an additive package. The test results showed that the 10 percent surface fatigue (pitting) life of the contour hardened AISI 1552 test gears was 1.7 times that of the carburized and hardened AISI 9310 test gears. Also there were two early failures of the AISI 1552 gears by bending fatigue.

  8. Influence of Cultivar on the Postharvest Hardening of Trifoliate Yam (Dioscorea dumetorum Tubers

    Directory of Open Access Journals (Sweden)

    Christian Siadjeu

    2016-01-01

    Full Text Available The influence of cultivar on the postharvest hardening of Dioscorea dumetorum tubers was assessed. 32 cultivars of D. dumetorum tubers were planted in April 2014, harvested at physiological maturity, and stored under prevailing tropical ambient conditions (19–28°C, 60–85% RH for 0, 5, 14, 21, and 28 days. Samples were evaluated for cooked hardness. Results showed that one cultivar, Ibo sweet 3, was not affected by the hardening phenomenon. The remaining 31 were all subject to the hardening phenomenon at different degree. Cooked hardness increased more rapidly in cultivars with many roots on the tuber surface compared to cultivars with few roots on the tuber surface. When both the characteristics flesh colour and number of roots on tuber surface were associated, cooked hardness in cultivars with yellow flesh and many roots increased more rapidly than in cultivars with white flesh and many roots, whereas cooked hardness in cultivars with yellow flesh and few roots increased more slowly than in cultivars with white flesh and few roots. Accessions collected in high altitude increased more rapidly compared to accessions collected in low altitude. The cultivar Ibo sweet 3 identified in this study could provide important information for breeding program of D. dumetorum against postharvest hardening phenomenon.

  9. Temperature Development during Hardening of Large Concrete Cubes

    DEFF Research Database (Denmark)

    Sørensen, Eigil V.; Burcharth, Hans Falk

    The purpose ofthe project is to verify ifthermal cracking will occur in large unreinforced concrete cubes due to large temperature differences during hardening o f the concrete. The first part o f the project is to numerically simulate the temperature development during hardening, evaluate the risk...

  10. Analysis of the work-hardening process in spheroidized steels

    International Nuclear Information System (INIS)

    Pacheco, J.L.

    1981-07-01

    An elementary model for the work-hardening process in duplex-structures steels (ferrite - spheroidite) is proposed and tested on low, medium and high carbon content, which seems to give good results concerning the influence of the volume fraction and particle size of the second phase on the work-hardening behaviour. (Author) [pt

  11. Design and characterization of cellulose nanocrystal-enhanced epoxy hardeners

    Science.gov (United States)

    Shane X. Peng; Robert J. Moon; Jeffrey P. Youngblood

    2014-01-01

    Cellulose nanocrystals (CNCs) are renewable, sustainable, and abundant nanomaterial widely used as reinforcing fillers in the field of polymer nanocomposites. In this study, two-part epoxy systems with CNC-enhanced hardeners were fabricated. Three types of hardeners, Jeffamine D400 (JD400), diethylenetriamine (DETA), and (±)-trans-1,2- diaminocyclohexane (DACH), were...

  12. Optimization of Laser Beam Transformation Hardening by One Single Parameter

    NARCIS (Netherlands)

    Meijer, J.; van Sprang, I.

    1991-01-01

    The process of laser beam transformation hardening is principally controlled by two independent parameters, the absorbed laser power on a given area and the interaction time. These parameters can be transformed into two functional parameters: the maximum surface temperature and the hardening depth.

  13. Hardening fertilization and nutrient loading of conifer seedlings

    Science.gov (United States)

    R. Kasten Dumroese

    2003-01-01

    Continuing to fertilize bareroot and container seedlings during the hardening process (from cessation of height growth until lifting) can improve seedling viability. The process of fertilizing during hardening has many names, but in the last decade a new term, nutrient loading, has come into use. The process of nutrient loading seedlings leads to luxury consumption...

  14. Bake hardening of nanograin AA7075 aluminum alloy

    International Nuclear Information System (INIS)

    Dehghani, Kamran

    2011-01-01

    Highlights: ► The bake hardening behavior of AA7075 was studied and compared with its coarse-grain counterpart. ► Nanograin AA7075 exhibited 88–100% increase in bake hardenability. ► Nanograin AA7075 exhibited 36–38% increase in final yield strength after baking. ► Maximum bake hardenability and final yield stress were about 185 MPa and 719 MPa. - Abstract: In the present work, the bake hardening of nanostructured AA7075 aluminum alloy was compared with that of its coarse-grain counterpart. Surface severe plastic deformation (SSPD) was used to produce nanograin layers on both surfaces of workpieces. The nanostructured layers were characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. The thickness of nanostructured layer, having the grains of 50–110 nm, was about 75 μm on each side of workpiece. The bake hardenability of nanograin and coarse-grain AA7075 was then compared by pre-straining to 2, 4 and 6% followed by baking at 100 °C and 200 °C for 20 min. Comparing to coarse-grain case, there was about 88–100% increase in bake hardenability and about 36–38% increase in yield strength after the bake hardening of present nanograin AA7075. Such an increase in bake hardenability and strength was achieved when the thickness of two nanograin layers was about only one-tenth of the whole thickness.

  15. The effects of alloying elements on strength, hardenability, and ...

    African Journals Online (AJOL)

    Tensile and hardenability tests were carried out. Results showed that alloying elements in steel increased strength in the dual phase steels by amounts ranging from 150 Mpa for Nb-V steel to 226 MPa for Nb steel. Strain hardening exponent, n, was also increased from ~0.22 for annealed to 0.35 in the dual phase steels.

  16. Work hardening correlation for monotonic loading based on state variables

    International Nuclear Information System (INIS)

    Huang, F.H.; Li, C.Y.

    1977-01-01

    An absolute work hardening correlation in terms of the hardness parameter and the internal stress based on the state variable approach was developed. It was found applicable to a variety of metals and alloys. This correlation predicts strain rate insensitive work hardening properties at low homologous temperatures and produces strain rate effects at higher homologous temperatures without involving thermally induced recovery processes

  17. system hardening architecture for safer access to critical business

    African Journals Online (AJOL)

    eobe

    cation, operating system, user, and the physical layers. This architecture is proposed on the premise that the premise that organisations implementing system hardening security approaches experience safer access to rganisations implementing system hardening security approaches experience safer access to data, as well.

  18. Induction surface hardening of hard coated steels

    DEFF Research Database (Denmark)

    Pantleon, Karen; Kessler, Olaf; Hoffmann, Franz

    1999-01-01

    after the deposition of TiN hard coatings on steel substrates. Influences of both the coating properties and the substrate properties are discussed in dependence on the parameters of induction heating. Thereby the heating time, heating atmosphere and the power input into the specimen are changed......The deposition of hard coatings with CVD-processes is commonly used to improve the wear resistance e.g. of tool steels in forming. The advantages of CVD are undisputed (high deposition rates with simple equipment, excellent coating properties). Nevertheless, the disadvantage of the CVD....... The effect of induction surface hardening on the properties of the coating-substrate-systems is mainly characterized using investigations of microstructure and chemical composition as well as measurements of hardness and residual stresses in dependence on the distance from the surface. Furthermore...

  19. Coating compositions hardenable by ionization beams

    International Nuclear Information System (INIS)

    Chaudhari, D.; Haering, E.; Dobbelstein, A.; Hoselmann, W.

    1976-01-01

    Coating compositions hardenable by ionizing radiation comprise as binding agents a mixture of A. at least 1 unsaturated olefin compound containing urethane groups, and B. at least 1 further unsaturated olefin compound that may be copolymerized. The unsaturated olefin compound A. containing the urethane groups in a reaction product of (a) a compound of the general formula (CHR 1 = CR 2 COOCH 2 CH(OH)CH 2 O CO-)/sub n/R where n is 1 or 2, where R stands for a straight chain or branched alkyl group of valence n, where R 1 is hydrogen, methyl; or the group -COOCH 2 CH(OH)CH 2 OCOR 3 - where R 3 is a monovalent alkyl residue and where R 2 is hydrogen or methyl, and (b) a compound containing at least 1 isocyanate group where the mixture of (A) and (B) may contain conventional additives of the lacquer industry. 6 claims

  20. Novel SEU hardened PD SOI SRAM cell

    Science.gov (United States)

    Chengmin, Xie; Zhongfang, Wang; Xihu, Wang; Longsheng, Wu; Youbao, Liu

    2011-11-01

    A novel SEU hardened 10T PD SOI SRAM cell is proposed. By dividing each pull-up and pull-down transistor in the cross-coupled inverters into two cascaded transistors, this cell suppresses the parasitic BJT and source-drain penetration charge collection effect in PD SOI transistor which causes the SEU in PD SOI SRAM. Mixed-mode simulation shows that this novel cell completely solves the SEU, where the ion affects the single transistor. Through analysis of the upset mechanism of this novel cell, SEU performance is roughly equal to the multiple-cell upset performance of a normal 6T SOI SRAM and it is thought that the SEU performance is 17 times greater than traditional 6T SRAM in 45nm PD SOI technology node based on the tested data of the references. To achieve this, the new cell adds four transistors and has a 43.4% area overhead and performance penalty.

  1. The Natural Aging Effect on Hardenability in Al-Mg-Si: A Complex Interaction between Composition and Heat Treatment Parameters

    Directory of Open Access Journals (Sweden)

    Alex Poznak

    2018-05-01

    Full Text Available The technological relevance of Al-Mg-Si alloys has been rapidly growing over the last decade. Of particular interest to current and future applications is the problematic negative effect of prior natural aging on subsequent artificial age hardening. The influence of natural aging is dependent on both processing and compositional variables and has origins that are far from well-understood. This work examines the hardenability of 6000 series alloys under a wide range of conditions, paying particular attention to the natural aging effect. Experimental variables include alloy composition (Mg + Si, Mg/Si, cooling rate after solutionization, and duration of prior natural aging. Hardenability was evaluated with full hardness and conductivity aging curves for each condition, as well as select Transmission Electron Microscopy (TEM. Results are discussed based on the actions of naturally aged solute clusters during artificial aging. In particular, a complex interaction between vacancy concentration, cluster stability, and precipitation driving force is suggested.

  2. Environmental hardening of robots for nuclear maintenance and surveillance tasks

    International Nuclear Information System (INIS)

    Hintenlang, D.E.; Tulenko, J.S.; Wheeler, R.; Roy, T.

    1990-01-01

    The University of Florida, in cooperation with the Universities of Texas, Tennessee, and Michigan and Oak Ridge National Laboratory, is developing an advanced robotic system for the US Department of Energy under the University Program for Robotics for Advanced Reactors. As part of this program, the University of Florida has been pursuing the development of environmentally hardened components so that autonomous robotic systems can successfully carry out their tasks under the most extreme expected environmental conditions. This requirement means that the designed robotic system with its onboard computer-based intelligence must be able to successfully complete tasks in toxic, radioactive, wet, temperature extremes, and other physically impairing environments. As part of this program, a study was carried out to determine the environmental conditions that should be set as the design criteria for robotic systems to maintain reasonable operations for nuclear plants in the course of maintenance, testing, and surveillance under all conditions, including plant upset. It was decided that Florida would build a combined environmental testing facility to test specific devices in high-radiation/high-temperature combined environments. This environmental test chamber has been built and successfully tested to over 250 degree F. This facility will provide some of the first combined temperatures/radiation data for many large-scale integrated components

  3. Stress corrosion cracking evaluation of martensitic precipitation hardening stainless steels

    Science.gov (United States)

    Humphries, T. S.; Nelson, E. E.

    1980-01-01

    The resistance of the martensitic precipitation hardening stainless steels PH13-8Mo, 15-5PH, and 17-4PH to stress corrosion cracking was investigated. Round tensile and c-ring type specimens taken from several heats of the three alloys were stressed up to 100 percent of their yield strengths and exposed to alternate immersion in salt water, to salt spray, and to a seacoast environment. The results indicate that 15-5PH is highly resistant to stress corrosion cracking in conditions H1000 and H1050 and is moderately resistant in condition H900. The stress corrosion cracking resistance of PH13-8Mo and 17-4PH stainless steels in conditions H1000 and H1050 was sensitive to mill heats and ranged from low to high among the several heats included in the tests. Based on a comparison with data from seacoast environmental tests, it is apparent that alternate immersion in 3.5 percent salt water is not a suitable medium for accelerated stress corrosion testing of these pH stainless steels.

  4. Simulation of Hardening and Cooling Processes for Moving Melts in Special Casting Technologies

    Directory of Open Access Journals (Sweden)

    R. I. Esman

    2008-01-01

    Full Text Available A mathematical model and an algorithm for numerical solution of conjugate problem concerning hydrodynamics and heat transfer of hardening and cooling processes with liquid metal flow is given in the paper.Quantitative relationships between heating and hydrodynamic parameters of moving melts in the channels of metallic molds of special casting technologies have been determined in the paper. The analysis of temperature pattern and velocity field makes it possible to reveal an influence of boundary conditions on melt flow structure.

  5. Simulating irradiation hardening in tungsten under fast neutron irradiation including Re production by transmutation

    Science.gov (United States)

    Huang, Chen-Hsi; Gilbert, Mark R.; Marian, Jaime

    2018-02-01

    Simulations of neutron damage under fusion energy conditions must capture the effects of transmutation, both in terms of accurate chemical inventory buildup as well as the physics of the interactions between transmutation elements and irradiation defect clusters. In this work, we integrate neutronics, primary damage calculations, molecular dynamics results, Re transmutation calculations, and stochastic cluster dynamics simulations to study neutron damage in single-crystal tungsten to mimic divertor materials. To gauge the accuracy and validity of the simulations, we first study the material response under experimental conditions at the JOYO fast reactor in Japan and the High Flux Isotope Reactor at Oak Ridge National Laboratory, for which measurements of cluster densities and hardening levels up to 2 dpa exist. We then provide calculations under expected DEMO fusion conditions. Several key mechanisms involving Re atoms and defect clusters are found to govern the accumulation of irradiation damage in each case. We use established correlations to translate damage accumulation into hardening increases and compare our results to the experimental measurements. We find hardening increases in excess of 5000 MPa in all cases, which casts doubts about the integrity of W-based materials under long-term fusion exposure.

  6. Microstructure and age-hardening effects of aluminium alloys with additions of scandium and zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Galun, R.; Mordike, B.L. [Inst. fuer Werkstoffkunde und Werkstofftechnik, Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany); Maiwald, T.; Smola, B. [Zentrum fuer Funktionswerkstoffe GmbH, Clausthal-Zellerfeld (Germany); Mergen, R.; Manner, M.; Uitz, W. [Miba Gleitlager GmbH, Laakirchen (Australia)

    2004-12-01

    The aim of the work presented in this report was to produce age-hardenable aluminium alloys containing scandium and zirconium by a casting process with similar cooling conditions like an industrial casting process. Microstructure, precipitation structure and age-hardening response of different alloys with up to 0.4 wt.% Sc and Zr were investigated. Age-hardening experiments from the as-cast condition without solution annealing showed a significant increase of hardness of about 100% for Sc-rich alloys and of 50% for Zr-rich alloys compared to the as-cast condition. TEM investigations revealed the formation of precipitates of ternary Al{sub 3}(Sc{sub x}Zr{sub 1-x}) phases with a cubic cP4 crystal structure. In addition to the strengthening effect, a high thermal stability especially of the precipitates in Zr-rich alloys up to 400 C let these alloys look very promising for high-temperature applications. (orig.)

  7. Conservation Research and Development/ New Ultra-Low Carbon High Strength Steels with Improved Bake Hardenability for Enhanced Stretch Formability and Dent Resistance

    Energy Technology Data Exchange (ETDEWEB)

    Anthony J. DeArdo; C. Isaac Garcia

    2003-12-15

    Conservation Research and Development/New Ultra-Low Carbon High Strength Steels with Improved Bake Hardenability for Enhanced Stretch Formability and Dent Resistance. The experimental work can be divided into four phases. In each phase, the materials were received or designed, processed and tested, to evaluate the BH increment or response, as a function of compositions and processing conditions. Microstructural characterization by various techniques was performed in order to gain insights into the mechanisms of flow stress increment by bake hardening.

  8. Cyber situational awareness and differential hardening

    Science.gov (United States)

    Dwivedi, Anurag; Tebben, Dan

    2012-06-01

    The advent of cyber threats has created a need for a new network planning, design, architecture, operations, control, situational awareness, management, and maintenance paradigms. Primary considerations include the ability to assess cyber attack resiliency of the network, and rapidly detect, isolate, and operate during deliberate simultaneous attacks against the network nodes and links. Legacy network planning relied on automatic protection of a network in the event of a single fault or a very few simultaneous faults in mesh networks, but in the future it must be augmented to include improved network resiliency and vulnerability awareness to cyber attacks. Ability to design a resilient network requires the development of methods to define, and quantify the network resiliency to attacks, and to be able to develop new optimization strategies for maintaining operations in the midst of these newly emerging cyber threats. Ways to quantify resiliency, and its use in visualizing cyber vulnerability awareness and in identifying node or link criticality, are presented in the current work, as well as a methodology of differential network hardening based on the criticality profile of cyber network components.

  9. Open Source Radiation Hardened by Design Technology

    Science.gov (United States)

    Shuler, Robert

    2016-01-01

    The proposed technology allows use of the latest microcircuit technology with lowest power and fastest speed, with minimal delay and engineering costs, through new Radiation Hardened by Design (RHBD) techniques that do not require extensive process characterization, technique evaluation and re-design at each Moore's Law generation. The separation of critical node groups is explicitly parameterized so it can be increased as microcircuit technologies shrink. The technology will be open access to radiation tolerant circuit vendors. INNOVATION: This technology would enhance computation intensive applications such as autonomy, robotics, advanced sensor and tracking processes, as well as low power applications such as wireless sensor networks. OUTCOME / RESULTS: 1) Simulation analysis indicates feasibility. 2)Compact voting latch 65 nanometer test chip designed and submitted for fabrication -7/2016. INFUSION FOR SPACE / EARTH: This technology may be used in any digital integrated circuit in which a high level of resistance to Single Event Upsets is desired, and has the greatest benefit outside low earth orbit where cosmic rays are numerous.

  10. Plasma Methods of Obtainment of Multifunctional Composite Materials, Dispersion-Hardened by Nanoparticles

    Science.gov (United States)

    Sizonenko, O. N.; Grigoryev, E. G.; Pristash, N. S.; Zaichenko, A. D.; Torpakov, A. S.; Ye, V. Lypian; Tregub, V. A.; Zholnin, A. G.; Yudin, A. V.; Kovalenko, A. A.

    2017-09-01

    High voltage electric discharge (HVED) in disperse system "hydrocarbon liquid - powder" due to impact of plasma discharge channel, electromagnetic fields, shock waves mechanical impact, hydro flows and volume microcavitation leads to synthesis of nanocarbon, metal powders dispersion and synthesis of micro- (from 10-6 to 10-7 m) and nanosized (from 10-7 to 10-9 m) composite powders of hardening phases. Spark plasma sintering (SPS) of powder mixtures allows targeted control of grain growth rate and thus allows obtainment of multifunctional composite materials dispersion hardened by nanoparticles. Processes of HVED synthesis of micro- and nanosized powders of new compositions from elemental metal powders and their mixtures with the subsequent application of high-speed SPS of obtained powders create conditions for increase of strength (by 10-20 %), hardness and wear-resistance (by 30-60 %) of obtained materials.

  11. The engineering of soft ferromagnetic plane by AISI 304 hardening process

    Science.gov (United States)

    Mubarok, Naila; Notonegoro, Hamdan Akbar; Thosin, Kemas Ahmad Zaini; Manaf, Azwar

    2017-01-01

    Austenitic stainless steels AISI 304 are widely used in engineering applications for various industrial applications. In basic condition, AISI 304 is non-magnetic. Shifting the structure through the hardening process will affect the magnetic properties. This technique makes it possible to produce soft ferromagnetic material through mechanical processes. A percentage of thinning rate correlated linearly with the thickness of the sample. Sizeable changing occurred at 21-30 HVC. The hysteresis curve shows the soft ferromagnetic property with small coercivity. The magnetic value significantly increased found at 344 HVC to 371 HVC and maximum when reaching 425 HVC. We suggest a 60% of thinning as a better hardening process for manufacturing soft ferromagnetic material from AISI 304.

  12. Metabolomic profiling of heat stress: hardening and recovery of homeostasis in Drosophila

    DEFF Research Database (Denmark)

    Malmendal, Anders; Overgaard, Johannes; Bundy, Jacob G

    2006-01-01

    homeostasis after subsequent heat stress. Several metabolites were identified as responsive to heat stress and could be related to known physiological and biochemical responses. The time course of the recovery of metabolite homeostasis mirrored general changes in gene expression, showing that recovery follows...... the same temporal pattern at these two biological levels. Finally, our data show that heat hardening permits a quicker return to homeostasis, rather than a reduction of the acute metabolic perturbation and that the reestablishment of homeostasis is important for obtaining maximal heat-hardening effect....... The results display the power of NMR metabolomic profiling for characterization of the instantaneous physiological condition, enabling direct visualization of the perturbation of and return to homeostasis....

  13. Optimization of processing parameters in induction hardening using ...

    Indian Academy of Sciences (India)

    ; response surface methodology. 1. Introduction. Since 1980's the processes of surface strengthening (hardening) of steel with the use of high fre- quency induction (Miller & Lagoudas 1980) have found ever-increasing applications to improve.

  14. Technologies Enabling Custom Radiation-Hardened Component Development, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Two primary paths are available for the creation of a Rad-Hard ASIC. The first approach is to use a radiation hardened process such as existing Rad-Hard foundries....

  15. Technologies Enabling Custom Radiation-Hardened Component Development Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Two primary paths are available for the creation of a Rad-Hard ASIC. The first approach is to use a radiation hardened process such as existing Rad-Hard foundries....

  16. Radiation hardening of power MOSFETs using electrical stress

    International Nuclear Information System (INIS)

    Picard, C.; Brisset, C.; Quittard, O.; Joffre, F.; Picard, C.; Hoffmann, A.; Charles, J.P.

    1999-01-01

    Application of high voltage electrical stresses to NVDMOSFET-type COTS transistors was explored as an original hardening option. Such pre irradiation treatment enhances transistor response to total dose, with a resulting gain of up to one decade. (authors)

  17. Radiation Hardened Ethernet PHY and Switch Fabric, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Innoflight will develop a new family of radiation hardened (up to 3 Mrad(Si)), fault-tolerant, high data-rate (up to 8 Gbps), low power Gigabit Ethernet PHY and...

  18. Space Qualified, Radiation Hardened, Dense Monolithic Flash Memory, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Radiation hardened nonvolatile memories for space is still primarily confined to EEPROM. There is high density effective or cost effective NVM solution available to...

  19. Space Qualified, Radiation Hardened, Dense Monolithic Flash Memory, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Space Micro proposes to build a radiation hardened by design (RHBD) flash memory, using a modified version of our RH-eDRAM Memory Controller to solve all the single...

  20. A Radiation Hardened Housekeeping Slave Node (RH-HKSN) ASIC

    Data.gov (United States)

    National Aeronautics and Space Administration — This projects seeks to continue the development of the Radiation Hardened Housekeeping Slave Node (RH-HKSN) ASIC. The effort has taken parallel paths by implementing...

  1. Radiation hardening of metals irradiated by heavy ions

    International Nuclear Information System (INIS)

    Didyk, A.Yu.; Skuratov, V.A.; Mikhajlova, N.Yu.; Regel', V.R.

    1988-01-01

    The damage dose dependence in the 10 -4 -10 -2 dpa region of radiation hardening of Al, V, Ni, Cu irradiated by xenon ions with 124 MeV energy is investigated using the microhardness technique and transmission electron microscope. It is shown that the pure metals radiation hardening is stimulated for defects clusters with the typical size less than 5 nm, as in the case of neutron and the light charge ion irradiation

  2. Radiation-hardened bulk Si-gate CMOS microprocessor family

    International Nuclear Information System (INIS)

    Stricker, R.E.; Dingwall, A.G.F.; Cohen, S.; Adams, J.R.; Slemmer, W.C.

    1979-01-01

    RCA and Sandia Laboratories jointly developed a radiation-hardened bulk Si-gate CMOS technology which is used to fabricate the CDP-1800 series microprocessor family. Total dose hardness of 1 x 10 6 rads (Si) and transient upset hardness of 5 x 10 8 rads (Si)/sec with no latch up at any transient level was achieved. Radiation-hardened parts manufactured to date include the CDP-1802 microprocessor, the CDP-1834 ROM, the CDP-1852 8-bit I/O port, the CDP-1856 N-bit 1 of 8 decoder, and the TCC-244 256 x 4 Static RAM. The paper is divided into three parts. In the first section, the basic fundamentals of the non-hardened C 2 L technology used for the CDP-1800 series microprocessor parts is discussed along with the primary reasons for hardening this technology. The second section discusses the major changes in the fabrication sequence that are required to produce radiation-hardened devices. The final section details the electrical performance characteristics of the hardened devices as well as the effects of radiation on device performance. Also included in this section is a discussion of the TCC-244 256 x 4 Static RAM designed jointly by RCA and Sandia Laboratories for this application

  3. Press-Hardening Simulation - the next Level of Maturity

    Science.gov (United States)

    Schönbach, T.; Messner, M.; Gmainer, C.

    2017-09-01

    Press hardening has been fully established in the automotive industry during the last years. Forming simulation is an important tool to make the whole potential of press hardening available in both, the mass production and further developments. One of the usual simulation packages is AutoForm. It has been known as a reliable software tool for the sheet metal forming application area as well as for the press hardening for years. AutoForm-Thermo Solverplus supports direct and indirect hot forming, which are followed by quenching and cooling processes. It takes into account phase transformation during quenching and thermal distortion after cooling. The recent version AutoFormplus R7 brings further advances in process modeling for hot forming as this release allows users to take into account cooling channels. Based on this, the heat conduction in tools can be calculated. Cooling channel modelling affects press hardening simulation in two ways: it can be used to optimize the cooling channel design in the press hardening tools and it increases the accuracy level of the simulation in general. The resulting benefits coming from these new features will be presented in this paper; based on a B-pillar which was produced with direct press-hardening process.

  4. Extracting material response from simple mechanical tests on hardening-softening-hardening viscoplastic solids

    Science.gov (United States)

    Mohan, Nisha

    Compliant foams are usually characterized by a wide range of desirable mechanical properties. These properties include viscoelasticity at different temperatures, energy absorption, recoverability under cyclic loading, impact resistance, and thermal, electrical, acoustic and radiation-resistance. Some foams contain nano-sized features and are used in small-scale devices. This implies that the characteristic dimensions of foams span multiple length scales, rendering modeling their mechanical properties difficult. Continuum mechanics-based models capture some salient experimental features like the linear elastic regime, followed by non-linear plateau stress regime. However, they lack mesostructural physical details. This makes them incapable of accurately predicting local peaks in stress and strain distributions, which significantly affect the deformation paths. Atomistic methods are capable of capturing the physical origins of deformation at smaller scales, but suffer from impractical computational intensity. Capturing deformation at the so-called meso-scale, which is capable of describing the phenomenon at a continuum level, but with some physical insights, requires developing new theoretical approaches. A fundamental question that motivates the modeling of foams is `how to extract the intrinsic material response from simple mechanical test data, such as stress vs. strain response?' A 3D model was developed to simulate the mechanical response of foam-type materials. The novelty of this model includes unique features such as the hardening-softening-hardening material response, strain rate-dependence, and plastically compressible solids with plastic non-normality. Suggestive links from atomistic simulations of foams were borrowed to formulate a physically informed hardening material input function. Motivated by a model that qualitatively captured the response of foam-type vertically aligned carbon nanotube (VACNT) pillars under uniaxial compression [2011,"Analysis of

  5. High-Performance, Radiation-Hardened Electronics for Space Environments

    Science.gov (United States)

    Keys, Andrew S.; Watson, Michael D.; Frazier, Donald O.; Adams, James H.; Johnson, Michael A.; Kolawa, Elizabeth A.

    2007-01-01

    The Radiation Hardened Electronics for Space Environments (RHESE) project endeavors to advance the current state-of-the-art in high-performance, radiation-hardened electronics and processors, ensuring successful performance of space systems required to operate within extreme radiation and temperature environments. Because RHESE is a project within the Exploration Technology Development Program (ETDP), RHESE's primary customers will be the human and robotic missions being developed by NASA's Exploration Systems Mission Directorate (ESMD) in partial fulfillment of the Vision for Space Exploration. Benefits are also anticipated for NASA's science missions to planetary and deep-space destinations. As a technology development effort, RHESE provides a broad-scoped, full spectrum of approaches to environmentally harden space electronics, including new materials, advanced design processes, reconfigurable hardware techniques, and software modeling of the radiation environment. The RHESE sub-project tasks are: SelfReconfigurable Electronics for Extreme Environments, Radiation Effects Predictive Modeling, Radiation Hardened Memory, Single Event Effects (SEE) Immune Reconfigurable Field Programmable Gate Array (FPGA) (SIRF), Radiation Hardening by Software, Radiation Hardened High Performance Processors (HPP), Reconfigurable Computing, Low Temperature Tolerant MEMS by Design, and Silicon-Germanium (SiGe) Integrated Electronics for Extreme Environments. These nine sub-project tasks are managed by technical leads as located across five different NASA field centers, including Ames Research Center, Goddard Space Flight Center, the Jet Propulsion Laboratory, Langley Research Center, and Marshall Space Flight Center. The overall RHESE integrated project management responsibility resides with NASA's Marshall Space Flight Center (MSFC). Initial technology development emphasis within RHESE focuses on the hardening of Field Programmable Gate Arrays (FPGA)s and Field Programmable Analog

  6. Non-destructive screening method for radiation hardened performance of large scale integration

    International Nuclear Information System (INIS)

    Zhou Dong; Xi Shanbin; Guo Qi; Ren Diyuan; Li Yudong; Sun Jing; Wen Lin

    2013-01-01

    The space radiation environment could induce radiation damage on the electronic devices. As the performance of commercial devices is generally superior to that of radiation hardened devices, it is necessary to screen out the devices with good radiation hardened performance from the commercial devices and applying these devices to space systems could improve the reliability of the systems. Combining the mathematical regression analysis with the different physical stressing experiments, we investigated the non-destructive screening method for radiation hardened performance of the integrated circuit. The relationship between the change of typical parameters and the radiation performance of the circuit was discussed. The irradiation-sensitive parameters were confirmed. The pluralistic linear regression equation toward the prediction of the radiation performance was established. Finally, the regression equations under stress conditions were verified by practical irradiation. The results show that the reliability and accuracy of the non-destructive screening method can be elevated by combining the mathematical regression analysis with the practical stressing experiment. (authors)

  7. A constitutive equation of creep based on recoverable creep hardening range

    International Nuclear Information System (INIS)

    Murakami, Sumio; Ohno, Nobutada

    1982-01-01

    In case of the stress reverse test of 304 stainless steel under constant stress, the creep curve after stress reverse is not much different from that for the initial state, accordingly, the state of hardening of the material is restored almost to that in the initial state by stress reverse. Creep depends on past loading history, and essentially is anisotropic phenomenon. In this study, by extending the strain hardening theory to general multi-axial stress condition, a constitutive formula for creep without any difficulty was determined. For the purpose, as the main change of microscopic structure at the time of stress reverse in mono-axial creep, the effect of the reactivation of passive dislocations was considered. At this time, the range of recoverable creep hardening was assumed, in which irreversible dislocation arrangement does not occur after stress reverse. In order to examine the propriety of this theory, the multi-axial creep deformation, of which the principal stress direction changes periodically, was calculated by the derived constitutive formula, and the result was compared with the experimental result of 304 stainless steel tube at 650 deg C and the theoretical result of ORNL. (Kako, I.)

  8. Sensitivity of polycrystal plasticity to slip system kinematic hardening laws for Al 7075-T6

    International Nuclear Information System (INIS)

    Hennessey, Conor; Castelluccio, Gustavo M.; McDowell, David L.

    2017-01-01

    The prediction of formation and early growth of microstructurally small fatigue cracks requires use of constitutive models that accurately estimate local states of stress, strain, and cyclic plastic strain. However, few research efforts have attempted to systematically consider the sensitivity of overall cyclic stress-strain hysteresis and higher order mean stress relaxation and plastic strain ratcheting responses introduced by the slip system back-stress formulation in crystal plasticity, even for face centered cubic (FCC) crystal systems. This paper explores the performance of two slip system level kinematic hardening models using a finite element crystal plasticity implementation as a User Material Subroutine (UMAT) within ABAQUS, with fully implicit numerical integration. The two kinematic hardening formulations aim to reproduce the cyclic deformation of polycrystalline Al 7075-T6 in terms of both macroscopic cyclic stress-strain hysteresis loop shape, as well as ratcheting and mean stress relaxation under strain- or stress-controlled loading with mean strain or stress, respectively. The first formulation is an Armstrong-Frederick type hardening-dynamic recovery law for evolution of the back stress. This approach is capable of reproducing observed deformation under completely reversed uniaxial loading conditions, but overpredicts the rate of cyclic ratcheting and associated mean stress relaxation. The second formulation corresponds to a multiple back stress Ohno-Wang type hardening law with nonlinear dynamic recovery. The adoption of this back stress evolution law greatly improves the capability to model experimental results for polycrystalline specimens subjected to cycling with mean stress or strain. As a result, the relation of such nonlinear dynamic recovery effects are related to slip system interactions with dislocation substructures.

  9. Porosity and mechanically optimized PLGA based in situ hardening systems.

    Science.gov (United States)

    Schloegl, W; Marschall, V; Witting, M Y; Volkmer, E; Drosse, I; Leicht, U; Schieker, M; Wiggenhorn, M; Schaubhut, F; Zahler, S; Friess, W

    2012-11-01

    Goal of the present study was to develop and to characterize in situ-hardening, porous PLGA-based systems for their future application as bone grafting materials. Therefore, we investigated the precipitation behavior of formulations containing PLGA and a water-miscible solvent, DMSO, PEG 400, and NMP. To increase porosity, a pore forming agent (NaCMC) was added and to enhance mechanical properties of the system, an inorganic filler (α-TCP) was incorporated. The behavior upon contact with water and the influence of the prior addition of aqueous media on the morphology of the corresponding hardened implants were investigated. We proved cell-compatibility by live/dead assays for the hardened porous polymer/ceramic-composite scaffolds. The IsHS formulations can therefore be used to manufacture hardened scaffolds ex vivo by using molds with the desired shape and size. Cells were further successfully incorporated into the IsHS by precultivating the cells on the α-TCP-powder prior to their admixing to the formulation. However, cell viability could not be maintained due to toxicity of the tested solvents. But, the results demonstrate that in vivo cells should well penetrate, adhere, and proliferate in the hardened scaffolds. Consequently, we consider the in situ hardening system being an excellent candidate as a filling material for non-weight-bearing orthopedic indications, as the resulting properties of the hardened implant fulfill indication-specific needs like mechanical stability, elasticity, and porosity. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Developing Processing Routes for the Equal-Channel Angular Pressing of Age-Hardenable Aluminum Alloys

    Science.gov (United States)

    Duan, Zhi Chao; Chinh, Nguyen Q.; Xu, Cheng; Langdon, Terence G.

    2010-04-01

    The processing of age-hardenable aluminum alloys by equal-channel angular pressing (ECAP) was investigated using three different Al-Zn-Mg alloys. The results show that it is relatively easy to conduct the ECAP at an elevated temperature of 473 K, but this leads to a weakening of the alloy rather than a strengthening. The processing by ECAP may be performed successfully at room temperature provided it is conducted fairly quickly (within ~10 minutes) after quenching from the solution treatment. It is necessary also to optimize the solution treatment conditions for each alloy composition. Under optimum conditions, good strengthening is achieved even after a single pass in ECAP.

  11. conditions

    Directory of Open Access Journals (Sweden)

    M. Venkatesulu

    1996-01-01

    Full Text Available Solutions of initial value problems associated with a pair of ordinary differential systems (L1,L2 defined on two adjacent intervals I1 and I2 and satisfying certain interface-spatial conditions at the common end (interface point are studied.

  12. Influence of Hardening Model on Weld Residual Stress Distribution

    International Nuclear Information System (INIS)

    Mullins, Jonathan; Gunnars, Jens

    2009-06-01

    This study is the third stage of a project sponsored by the Swedish Radiation Safety Authority (SSM) to improve the weld residual stress modelling procedures currently used in Sweden. The aim of this study was to determine which material hardening model gave the best agreement with experimentally measured weld residual stress distributions. Two girth weld geometries were considered: 19mm and 65mm thick girth welds with Rin/t ratios of 10.5 and 2.8, respectively. The FE solver ABAQUS Standard v6.5 was used for analysis. As a preliminary step some improvements were made to the welding simulation procedure used in part one of the project. First, monotonic stress strain curves and a mixed isotropic/kinematic hardening model were sourced from the literature for 316 stainless steel. Second, more detailed information was obtained regarding the geometry and welding sequence for the Case 1 weld (compared with phase 1 of this project). Following the preliminary step, welding simulations were conducted using isotropic, kinematic and mixed hardening models. The isotropic hardening model gave the best overall agreement with experimental measurements; it is therefore recommended for future use in welding simulations. The mixed hardening model gave good agreement for predictions of the hoop stress but tended to under estimate the magnitude of the axial stress. It must be noted that two different sources of data were used for the isotropic and mixed models in this study and this may have contributed to the discrepancy in predictions. When defining a mixed hardening model it is difficult to delineate the relative contributions of isotropic and kinematic hardening and for the model used it may be that a greater isotropic hardening component should have been specified. The kinematic hardening model consistently underestimated the magnitude of both the axial and hoop stress and is not recommended for use. Two sensitivity studies were also conducted. In the first the effect of using a

  13. Influence of coolant motion on structure of hardened steel element

    Directory of Open Access Journals (Sweden)

    A. Kulawik

    2008-08-01

    Full Text Available Presented paper is focused on volumetric hardening process using liquid low melting point metal as a coolant. Effect of convective motion of the coolant on material structure after hardening is investigated. Comparison with results obtained for model neglecting motion of liquid is executed. Mathematical and numerical model based on Finite Element Metod is described. Characteristic Based Split (CBS method is used to uncouple velocities and pressure and finally to solve Navier-Stokes equation. Petrov-Galerkin formulation is employed to stabilize convective term in heat transport equation. Phase transformations model is created on the basis of Johnson-Mehl and Avrami laws. Continuous cooling diagram (CTPc for C45 steel is exploited in presented model of phase transformations. Temporary temperatures, phases participation, thermal and structural strains in hardening element and coolant velocities are shown and discussed.

  14. Branching structure and strain hardening of branched metallocene polyethylenes

    International Nuclear Information System (INIS)

    Torres, Enrique; Li, Si-Wan; Costeux, Stéphane; Dealy, John M.

    2015-01-01

    There have been a number of studies of a series of branched metallocene polyethylenes (BMPs) made in a solution, continuous stirred tank reactor (CSTR) polymerization. The materials studied vary in branching level in a systematic way, and the most highly branched members of the series exhibit mild strain hardening. An outstanding question is which types of branched molecules are responsible for strain hardening in extension. This question is explored here by use of polymerization and rheological models along with new data on the extensional flow behavior of the most highly branched members of the set. After reviewing all that is known about the effects of various branching structures in homogeneous polymers and comparing this with the structures predicted to be present in BMPs, it is concluded that in spite of their very low concentration, treelike molecules with branch-on-branch structure provide a large number of deeply buried inner segments that are essential for strain hardening in these polymers

  15. Branching structure and strain hardening of branched metallocene polyethylenes

    Energy Technology Data Exchange (ETDEWEB)

    Torres, Enrique; Li, Si-Wan; Costeux, Stéphane; Dealy, John M., E-mail: john.dealy@mcgill.ca [Department of Chemical Engineering, McGill University, Montreal, Quebec H3A 0C4 (Canada)

    2015-09-15

    There have been a number of studies of a series of branched metallocene polyethylenes (BMPs) made in a solution, continuous stirred tank reactor (CSTR) polymerization. The materials studied vary in branching level in a systematic way, and the most highly branched members of the series exhibit mild strain hardening. An outstanding question is which types of branched molecules are responsible for strain hardening in extension. This question is explored here by use of polymerization and rheological models along with new data on the extensional flow behavior of the most highly branched members of the set. After reviewing all that is known about the effects of various branching structures in homogeneous polymers and comparing this with the structures predicted to be present in BMPs, it is concluded that in spite of their very low concentration, treelike molecules with branch-on-branch structure provide a large number of deeply buried inner segments that are essential for strain hardening in these polymers.

  16. Effect of preheating on fatigue resistance of gears in spin induction coil hardening process

    Science.gov (United States)

    Kumar, Pawan; Aggarwal, M. L.

    2018-02-01

    Spin hardening inductors are typically used for fine-sized teeth gear geometry. With the proper selection of several design parameters, only the gear teeth can be case surface hardened without affecting the other surface of gear. Preheating may be done to reach an adapted high austenitizing temperature in the root circle to avoid overheating of the tooth tip during final heating. The effect of preheating of gear on control of compressive residual stresses and case hardening has been experimentally discussed in this paper. Present work is about analysing single frequency mode, preheat hardening treatment and compressive residual stresses field for hardening process of spur gear using spin hardening inductors.

  17. INFLUENCE OF MICROALLOYING BY BORON ON HARDENABILITY OF STEEL

    Directory of Open Access Journals (Sweden)

    E. P. Baradyntseva

    2016-01-01

    Full Text Available The research conducted in laboratory of metallurgical science by which the factors exerting impact on hardenability of steel microalloyed by boron were analysed. The research was made because the implementation of this process in mass production is connected with the certain difficulties. The conducted researches have allowed to draw a conclusion that changing content of various chemical elements, such as nitrogen, boron, the titan and aluminum in steel containing boron, produced by JSC «BSW – Management Company of Holding «BMC» at the stage of preparation of chart flowsheet make it possible to predict terms of hardenability of the final product.

  18. Microstructure and properties of cast iron after laser surface hardening

    Directory of Open Access Journals (Sweden)

    Stanislav

    2013-12-01

    Full Text Available Laser surface hardening of cast iron is not trivial due to the material’s heterogeneity and coarse-grained microstructure, particularly in massive castings. Despite that, hardening of heavy moulds for automotive industry is in high demand. The present paper summarises the findings collected over several years of study of materials structure and surface properties. Phase transformations in the vicinity of graphite are described using examples from production of body parts in automotive industry. The description relates to formation of martensite and carbide-based phases, which leads to hardness values above 65 HRC and to excellent abrasion resistance.

  19. Exploration of a radiation hardening stabilized voltage power supply

    International Nuclear Information System (INIS)

    Xie Zeyuan; Xu Xianguo

    2014-01-01

    This paper mainly introduces the design method of radiation hardening stabilized voltage power supply that makes use of commercial radiation resistant electronic devices and the test results of radiation performance of the power supply and devices are presented in detail. The experiment results show that the hardened power supply can normally work until 1000 Gy (Si) total dose and 1 × 10 14 n/cm 2 neutron radiation, and it doesn't latchup at about 1 × l0 9 Gy (Si)/s gamma transient dose rate. (authors)

  20. Why semiconductors must be hardened when used in space

    International Nuclear Information System (INIS)

    Winokur, P.S.

    2000-01-01

    The natural space radiation environment presents a great challenge to present and future satellite systems with significant assets in space. Defining requirements for such systems demands knowledge about the space radiation environment and its effects on electronics and optoelectronics technologies, as well as suitable risk assessment of the uncertainties involved. For mission of high radiation levels, radiation-hardened integrated circuits will be required to preform critical mission functions. The most successful systems in space will be those that are best able to blend standard commercial electronics with custom radiation-hardened electronics in a mix that is suitable for the system of interest

  1. Work hardening and plastic equation of state of tantalum

    International Nuclear Information System (INIS)

    Gypen, L.A.; Aernoudt, E.; Deruyttere, A.

    1983-01-01

    The influence of cold deformation on the thermal and athermal components of the flow stress of tantalum was investigated. Up to high deformation levels the strain hardening is due only to the development of internal stress fields; the effective stress remains almost constant. The athermal strain hardening of tantalum is parabolic at low deformation levels (epsilon < 0.5) and linear at high deformation levels, as for other bcc metals. Hart's plastic equation of state is shown to be valid for tantalum at room temperature in the whole deformation range investigated (from epsilon = 0.005 to epsilon = 2.8). (author)

  2. Non-conventional laser surface hardening for axisymmetric components

    Science.gov (United States)

    Liverani, Erica; Battiato, Nadine; Ascari, Alessandro; Fortunato, Alessandro

    2014-02-01

    A new process, based on ring spot geometry, is presented for laser surface hardening of large cylindrical com-ponents. The proposed technique leads to a very hard, deep and uniform treated area along the entire work piece surface without introducing a tempered zone, making the process very attractive compared to conventional induction hardening that exhibits both low energy efficiency and poor flexibility. A complete physical model is presented for the process, together with a study of the influence of process parameters on the final outcome. The results of an extensive validation campaign, carried out following the AISI1040 standard, are also reported.

  3. Impact of Scaled Technology on Radiation Testing and Hardening

    Science.gov (United States)

    LaBel, Kenneth A.; Cohn, Lewis M.

    2005-01-01

    This presentation gives a brief overview of some of the radiation challenges facing emerging scaled digital technologies with implications on using consumer grade electronics and next generation hardening schemes. Commercial semiconductor manufacturers are recognizing some of these issues as issues for terrestrial performance. Looking at means of dealing with soft errors. The thinned oxide has indicated improved TID tolerance of commercial products hardened by "serendipity" which does not guarantee hardness or say if the trend will continue. This presentation also focuses one reliability implications of thinned oxides.

  4. Changes in hardness of magnesium alloys due to precipitation hardening

    Directory of Open Access Journals (Sweden)

    Tatiana Oršulová

    2018-04-01

    Full Text Available This paper deals with the evaluation of changes in hardness of magnesium alloys during precipitation hardening that are nowadays widely used in different fields of industry. It focuses exactly on AZ31, AZ61 and AZ91 alloys. Observing material hardness changes serves as an effective tool for determining precipitation hardening parameters, such as temperature and time. Brinell hardness measurement was chosen based on experimental needs. There was also necessary to make chemical composition analysis and to observe the microstructures of tested materials. The obtained results are presented and discussed in this paper.

  5. Radiation Hardened 10BASE-T Ethernet Physical Layer (PHY)

    Science.gov (United States)

    Lin, Michael R. (Inventor); Petrick, David J. (Inventor); Ballou, Kevin M. (Inventor); Espinosa, Daniel C. (Inventor); James, Edward F. (Inventor); Kliesner, Matthew A. (Inventor)

    2017-01-01

    Embodiments may provide a radiation hardened 10BASE-T Ethernet interface circuit suitable for space flight and in compliance with the IEEE 802.3 standard for Ethernet. The various embodiments may provide a 10BASE-T Ethernet interface circuit, comprising a field programmable gate array (FPGA), a transmitter circuit connected to the FPGA, a receiver circuit connected to the FPGA, and a transformer connected to the transmitter circuit and the receiver circuit. In the various embodiments, the FPGA, transmitter circuit, receiver circuit, and transformer may be radiation hardened.

  6. Numerical simulations of progressive hardening by using ABAQUS FEA software

    Directory of Open Access Journals (Sweden)

    Domański Tomasz

    2018-01-01

    Full Text Available The paper concerns numerical simulations of progressive hardening include phase transformations in solid state of steel. Abaqus FEA software is used for numerical analysis of temperature field and phase transformations. Numerical subroutines, written in fortran programming language are used in computer simulations where models of the distribution of movable heat source, kinetics of phase transformations in solid state as well as thermal and structural strain are implemented. Model for evaluation of fractions of phases and their kinetics is based on continuous heating diagram and continuous cooling diagram. The numerical analysis of thermal fields, phase fractions and strain associated progressive hardening of elements made of steel were done.

  7. Aspect-oriented security hardening of UML design models

    CERN Document Server

    Mouheb, Djedjiga; Pourzandi, Makan; Wang, Lingyu; Nouh, Mariam; Ziarati, Raha; Alhadidi, Dima; Talhi, Chamseddine; Lima, Vitor

    2015-01-01

    This book comprehensively presents a novel approach to the systematic security hardening of software design models expressed in the standard UML language. It combines model-driven engineering and the aspect-oriented paradigm to integrate security practices into the early phases of the software development process. To this end, a UML profile has been developed for the specification of security hardening aspects on UML diagrams. In addition, a weaving framework, with the underlying theoretical foundations, has been designed for the systematic injection of security aspects into UML models. The

  8. Neutron-irradiation + helium hardening and embrittlement modeling of 9% Cr-steels in an engineering perspective (HELENA)

    Energy Technology Data Exchange (ETDEWEB)

    Chaouadi, Rachid

    2008-07-01

    This report provides a physically-based engineering model to estimate the radiation hardening of 9%Cr-steels under both displacement damage (dpa) and helium. The model is essentially based on the dispersed barrier hardening theory and the dynamic re-solution of helium under displacement cascades. However, a number of assumptions and simplifications were considered to obtain a simple description of irradiation hardening and embrittlement primarily relying on the available experimental data. As a result, two components were basically identified, the dpa component that can be associated with black dots and small loops and the He-component accounting for helium bubbles. The dpa component is strongly dependent on the irradiation temperature and its dependence law was based on a first-order annealing kinetics. The damage accumulation law was also modified to take saturation into account. Finally, the global kinetics of the damage accumulation kept defined, its amplitude is fitted to one experimental condition. The model was rationalized on an experimental database that mainly consists of {proportional_to}9%Cr-steels irradiated in the technologically important temperature range of 50 to 600 C up do 50 dpa and with a He-content up to {proportional_to}5000 appm, including neutron and proton irradiation as well as implantation. The test temperature effect is taken into account through a normalization procedure based on the change of the Young's modulus and the anelastic deformation that occurs at high temperature. Finally, the hardening-to-embrittlement correlation is obtained using the load diagram approach. Despite the large experimental scatter, inherent to the variety of the materials and irradiation as well as testing conditions, the obtained results are very promising. Improvement of the model performance is still possible by including He-hardening saturation and high temperature softening but unfortunately, at this stage, a number of conflicting experimental data

  9. Modeling copper precipitation hardening and embrittlement in a dilute Fe-0.3at.%Cu alloy under neutron irradiation

    Science.gov (United States)

    Bai, Xian-Ming; Ke, Huibin; Zhang, Yongfeng; Spencer, Benjamin W.

    2017-11-01

    Neutron irradiation in light water reactors can induce precipitation of nanometer sized Cu clusters in reactor pressure vessel steels. The Cu precipitates impede dislocation gliding, leading to an increase in yield strength (hardening) and an upward shift of ductile-to-brittle transition temperature (embrittlement). In this work, cluster dynamics modeling is used to model the entire Cu precipitation process (nucleation, growth, and coarsening) in a Fe-0.3at.%Cu alloy under neutron irradiation at 300°C based on the homogenous nucleation mechanism. The evolution of the Cu cluster number density and mean radius predicted by the modeling agrees well with experimental data reported in literature for the same alloy under the same irradiation conditions. The predicted precipitation kinetics is used as input for a dispersed barrier hardening model to correlate the microstructural evolution with the radiation hardening and embrittlement in this alloy. The predicted radiation hardening agrees well with the mechanical test results in the literature. Limitations of the model and areas for future improvement are also discussed in this work.

  10. Micro-mechanical modelling of ductile failure in 6005A aluminium using a physics based strain hardening larw including stage IV

    DEFF Research Database (Denmark)

    Simar, Aude; Nielsen, Kim Lau; de Meester, Bruno

    2010-01-01

    The strain hardening and damage behaviour of isothermally heat treated 6005A aluminium is investigated in order to link the thermal treatment conditions, microstructure and fracture strain. The need for a plastic flow rule involving a stage IV hardening at large strain was found essential...... allows for the simulation of the full tensile response curves up to cracking initiation and final failure. Reasonable agreement is found when comparing the predicted and experimentally measured fracture strains for a wide range of heat treatment conditions using real microstructure based parameters....

  11. Paving asphalts : reduction of oxidative hardening of asphalts by treatment with hydrated lime : a mechanistic study

    Science.gov (United States)

    1977-04-01

    This study showed that lime treatment removes polar, viscosity-building components and reduces the susceptibility of the asphalt to laboratory oxidative hardening. The beneficial effects of lime treatment in reducing asphalt oxidative hardening were ...

  12. Effect of hardening methods of moulding sands with water glass on structure of bonding bridges

    Directory of Open Access Journals (Sweden)

    M. Stachowicz

    2010-07-01

    Full Text Available Research on influence of hardening methods on structure of bonding bridges in moulding sands with sodium water glass is presented.Moulding sands with addition of 2.5 % of binder with molar module 2.0 were hardened with CO2 and dried in traditional way or hardenedwith microwaves. It was proved that the hardening method affects structure of bonding bridges, correlating with properties of the hardened moulding sands. It was found that strength of the moulding sands hardened with microwaves for 4 min is very close to that measured after traditional drying at 110 °C for 120 min. So, application of microwave hardening ensures significant shortening of the process time to the value comparable with CO2 hardening but guaranteeing over 10-fold increase of mechanical properties. Analysis of SEM images of hardened moulding sands permitted explaining differences in quality parameters of moulding sands by connecting them with structure of the created bonding bridges.

  13. Characterization of Steels Using a Revised Kinematic Hardening Model Incorporating Bauschinger Effect

    National Research Council Canada - National Science Library

    Parker, Anthony

    2002-01-01

    A new variant of the nonlinear kinematic hardening model is proposed that accommodates both nonlinear and linear strain hardening during initial tensile loading and reduced elastic modulus during initial load reversal...

  14. Differential hardening in IF steel - Experimental results and a crystal plasticity based model

    NARCIS (Netherlands)

    Mulder, J.; Eyckens, P.; van den Boogaard, Antonius H.; Hora, P.

    2015-01-01

    Work hardening in metals is commonly described by isotropic hardening, especially for monotonically increasing proportional loading. The relation between different stress states in this case is determined by equivalent stress and strain definitions, based on equal plastic dissipation. However,

  15. Radiation Hardened Electronics Destined For Severe Nuclear Reactor Environments

    Energy Technology Data Exchange (ETDEWEB)

    Holbert, Keith E. [Arizona State Univ., Tempe, AZ (United States); Clark, Lawrence T. [Arizona State Univ., Tempe, AZ (United States)

    2016-02-19

    Post nuclear accident conditions represent a harsh environment for electronics. The full station blackout experience at Fukushima shows the necessity for emergency sensing capabilities in a radiation-enhanced environment. This NEET (Nuclear Energy Enabling Technologies) research project developed radiation hardened by design (RHBD) electronics using commercially available technology that employs commercial off-the-shelf (COTS) devices and present generation circuit fabrication techniques to improve the total ionizing dose (TID) hardness of electronics. Such technology not only has applicability to severe accident conditions but also to facilities throughout the nuclear fuel cycle in which radiation tolerance is required. For example, with TID tolerance to megarads of dose, electronics could be deployed for long-term monitoring, inspection and decontamination missions. The present work has taken a two-pronged approach, specifically, development of both board and application-specific integrated circuit (ASIC) level RHBD techniques. The former path has focused on TID testing of representative microcontroller ICs with embedded flash (eFlash) memory, as well as standalone flash devices that utilize the same fabrication technologies. The standalone flash devices are less complicated, allowing better understanding of the TID response of the crucial circuits. Our TID experiments utilize biased components that are in-situ tested, and in full operation during irradiation. A potential pitfall in the qualification of memory circuits is the lack of rigorous testing of the possible memory states. For this reason, we employ test patterns that include all ones, all zeros, a checkerboard of zeros and ones, an inverse checkerboard, and random data. With experimental evidence of improved radiation response for unbiased versus biased conditions, a demonstration-level board using the COTS devices was constructed. Through a combination of redundancy and power gating, the demonstration

  16. Optimization of processing parameters in induction hardening using ...

    Indian Academy of Sciences (India)

    response surface methodology. 1. Introduction. Since 1980's the processes of surface strengthening (hardening) of steel with the use of high fre- quency induction (Miller & Lagoudas 1980) have found ever-increasing applications to improve the performance and life of parts used in aerospace and automobile engineering.

  17. The effects of alloying elements on strength, hardenability, and ...

    African Journals Online (AJOL)

    They were then air cooled before being cold rolled to ~0.9mm and annealed. Dual phase heat treatment was carried out at 755oC followed by quenching in water. Tensile and hardenability tests were carried out. Results showed that alloying elements in steel increased strength in the dual phase steels by amounts ranging ...

  18. Surface modification on PMMA: PVDF polyblend: hardening under ...

    Indian Academy of Sciences (India)

    The influence of chemical environment on polymers include the surface alteration as well as other deep modifications in surface layers. The surface hardening, as an effect of organic liquids on poly(methyl methacrylate): poly(vinylidene fluoride) (PMMA: PVDF), which is one of the few known miscible blends, has been ...

  19. Coefficient of work-hardening in stage-IV

    CSIR Research Space (South Africa)

    Nabarro, FRN

    1994-04-15

    Full Text Available The theory of work hardening in stage IV depends on the relation between the relative misorientation Psi of neighbouring subgrains and the plastic strain gamma (Psi = B gamma exp). The value of the constant B is suggested to be better related...

  20. Computed tomographic beam-hardening artefacts: mathematical characterization and analysis.

    Science.gov (United States)

    Park, Hyoung Suk; Chung, Yong Eun; Seo, Jin Keun

    2015-06-13

    This paper presents a mathematical characterization and analysis of beam-hardening artefacts in X-ray computed tomography (CT). In the field of dental and medical radiography, metal artefact reduction in CT is becoming increasingly important as artificial prostheses and metallic implants become more widespread in ageing populations. Metal artefacts are mainly caused by the beam-hardening of polychromatic X-ray photon beams, which causes mismatch between the actual sinogram data and the data model being the Radon transform of the unknown attenuation distribution in the CT reconstruction algorithm. We investigate the beam-hardening factor through a mathematical analysis of the discrepancy between the data and the Radon transform of the attenuation distribution at a fixed energy level. Separation of cupping artefacts from beam-hardening artefacts allows causes and effects of streaking artefacts to be analysed. Various computer simulations and experiments are performed to support our mathematical analysis. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  1. Radiogram enhancement and linearization using the beam hardening correction method

    Czech Academy of Sciences Publication Activity Database

    Vavřík, Daniel; Jakůbek, J.

    2009-01-01

    Roč. 607, - (2009), s. 212-214 ISSN 0168-9002. [International Workshop on Radiation Imaging Detectors. Helsinky, 29.06.2008-03.07.2008] Institutional research plan: CEZ:AV0Z20710524 Keywords : beam hardening correction * flat-field correction * digital radiography Subject RIV: JB - Sensors, Measurment, Regulation Impact factor: 1.317, year: 2009

  2. Influence of degree of deformation in rolling on anneal hardening ...

    Indian Academy of Sciences (India)

    Unknown

    The hardness, strength and electrical conductivity were measured and X-ray and DSC analyses performed. Anneal hardening effect was observed in the alloy in the temperature range 180–300°C, followed by an increase in the electrical conductivity. The amount of strengthening increases with increasing degree of prior.

  3. New Stainless Steel Alloys for Low Temperature Surface Hardening?

    DEFF Research Database (Denmark)

    Christiansen, Thomas Lundin; Dahl, Kristian Vinter; Somers, Marcel A. J.

    2015-01-01

    The present contribution showcases the possibility for developing new surface hardenable stainless steels containing strong nitride/carbide forming elements (SNCFE). Nitriding of the commercial alloys, austenitic A286, and ferritic AISI 409 illustrates the beneficial effect of having SNCFE present...

  4. Role of work hardening characteristics of matrix alloys in the ...

    Indian Academy of Sciences (India)

    The strengthening of particulate reinforced metal–matrix composites is associated with a high dislocation density in the matrix due to the difference in coefficient of thermal expansion between the reinforcement and the matrix. While this is valid, the role of work hardening characteristics of the matrix alloys in strengthening of ...

  5. Preparation of Dispersion-Hardened Copper by Internal Oxidation

    DEFF Research Database (Denmark)

    Brøndsted, Povl; Sørensen, Ole Toft

    1978-01-01

    Internal oxidation experiments in CO2/CO atmospheres on Cu-Al alloys for preparation of dispersion-hardened Cu are described. The oxygen pressures of the atmospheres used in the experiments were controlled with a solid electrolyte oxygen cell based on ZrO2 (CaO). The particle size distributions...

  6. Influence of alloying and secondary annealing on anneal hardening ...

    Indian Academy of Sciences (India)

    Unknown

    Influence of alloying and secondary annealing on anneal hardening effect at sintered copper alloys. SVETLANA NESTOROVIC. Technical Faculty Bor, University of Belgrade, Bor, Yugoslavia. MS received 11 February 2004; revised 29 October 2004. Abstract. This paper reports results of investigation carried out on sintered ...

  7. Influence of degree of deformation in rolling on anneal hardening ...

    Indian Academy of Sciences (India)

    Unknown

    Influence of degree of deformation in rolling on anneal hardening effect of a cast copper alloy. SVETLANA NESTOROVIC*, DESIMIR MARKOVIC and LJUBICA IVANIC. Technical Faculty Bor, University of Belgrade, Belgrade, Yugoslavia. MS received 15 May 2003. Abstract. This paper reports results of investigations carried ...

  8. Surface Induction Hardening of Axi-Symmetric Bodies

    Czech Academy of Sciences Publication Activity Database

    Barglik, J.; Doležel, Ivo; Škopek, M.; Ulrych, B.

    2001-01-01

    Roč. 1, č. 1 (2001), s. 11-16 ISSN 1335-8243 R&D Projects: GA ČR GA102/01/0184 Grant - others:-(PL) 7T08603716 Keywords : induction heating * induction hardening * numerical solution Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  9. Vacancy-induced hardening in Fe-Al alloys

    Czech Academy of Sciences Publication Activity Database

    Lukáč, F.; Čížek, J.; Procházka, I.; Jirásková, Yvonna; Janičkovič, D.; Anwand, W.; Brauer, G.

    2013-01-01

    Roč. 443, č. 1 (2013), 012025 ISSN 1742-6588. [International Conference on Positron Annihilation /16./. Bristol, 19.08.2012-24.08.2012] R&D Projects: GA ČR(CZ) GAP108/11/1350 Institutional support: RVO:68081723 Keywords : Vacancy * Hardening * Fe-Al alloy Subject RIV: BM - Solid Matter Physics ; Magnetism

  10. Mechanical Properties Of Quench-Hardened, Martempered And ...

    African Journals Online (AJOL)

    Some cast ASTM A grade B-4 steel samples were quench-hardened, martempered and tempered. The as-cast and heat-treated samples were thereafter tested for tensile strength, yield strength, impact strength, ductility and hardness. Some of the samples were also prepared for metallographic examination and their ...

  11. System Hardening Architecture for Safer Access to Critical Business ...

    African Journals Online (AJOL)

    System hardening is a defence strategy, where several different security measures are applied at various layers, all of which must be defeated before a module can be compromised. The protective mechanisms in this architecture are applied to the host, application, operating system, user, and the physical layers.

  12. Fatigue Hardening and Nucleation of Persistent Slip Bands in Copper

    DEFF Research Database (Denmark)

    Pedersen, Ole Bøcker; Winter, A. T.

    1982-01-01

    that there is a large volume fraction of obstacles to plastic flow which are essentially non-deformable and give rise to inclusion stresses of considerable magnitude. The much lower hardening rates in cycles after saturation when persistent slip bands have formed suggest a lower volume fraction of obstacles...

  13. BUSFET - A Novel Radiation-Hardened SOI Transistor

    International Nuclear Information System (INIS)

    Dodd, P.E.; Draper, B.L.; Schwank, J.R.; Shaneyfelt, M.R.

    1999-01-01

    A partially-depleted SOI transistor structure has been designed that does not require the use of specially-processed hardened buried oxides for total-dose hardness and maintains the intrinsic SEU and dose rate hardness advantages of SOI technology

  14. Self hardening property of Botswana fly ash | Sahu | Botswana ...

    African Journals Online (AJOL)

    In Botswana, it is being produced at the rate of more than 300 t per day at Morupule Power Station. Almost 70% of this production is disposed off as a waste and only 30% is being used in making cement. Few limited studies suggest that a fly ash containing low unburnt carbon (LOI) may exhibit self hardening property even ...

  15. Multiaxial ratcheting with advanced kinematic and directional distortional hardening rules

    Czech Academy of Sciences Publication Activity Database

    Feigenbaum, H. P.; Dugdale, J.; Dafalias, Y.F.; Kourousis, K. I.; Plešek, Jiří

    2012-01-01

    Roč. 49, č. 22 (2012), s. 3063-3076 ISSN 0020-7683 R&D Projects: GA MŠk(CZ) ME10024 Institutional research plan: CEZ:AV0Z20760514 Keywords : plasticity * directional distortional hardening * thermodynamics Subject RIV: JJ - Other Materials Impact factor: 1.871, year: 2012 http://www.sciencedirect.com/science/article/pii/S0020768312002612

  16. Continual Induction Hardening of Axi-Symmetric Bodies

    Czech Academy of Sciences Publication Activity Database

    Doležel, Ivo; Barglik, J.; Ulrych, B.

    2005-01-01

    Roč. 161, - (2005), s. 269-275 ISSN 0924-0136 R&D Projects: GA MŠk(CZ) LN00B084 Institutional research plan: CEZ:AV0Z20570509 Keywords : continual induction hardening * induction heating * electromagnetic field Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.592, year: 2005

  17. Precipitation Hardening of Castable Iron-Nickel Invars

    Science.gov (United States)

    Ogorodnikova, O. M.; Maksimova, E. V.

    2015-07-01

    Hardening of castable iron-nickel invars due to alloying with carbide-forming elements and carbon and subsequent heat treatment is investigated. It is shown that the strength of the invar alloys can be increased without raising the low values of the temperature coefficient of linear expansion.

  18. Evaluation of Local Vegetable Oils as Quenchants for Hardening ...

    African Journals Online (AJOL)

    However, the wear resistance of the quenched grey cast iron developed in this group of local vegetable oils was superior to that of SAE40 engine oil. The potentials of these oils as quenching media for grey cast iron hardening process ranked in descending order as soya bean, shea butter, groundnut, and palm kernel, with ...

  19. Decorative application of strain-hardening cementitious composites

    NARCIS (Netherlands)

    Ibrovic, V.; Lukovic, M.; Schlangen, E.

    2014-01-01

    Strain hardening cementitious composites (SHCC) have been used in variety of structural applications. Apart from this, they are also suitable for non-structural applications. In this work, the application of SHCC for producing cover plates for light switches and power sockets is presented. For

  20. The prediction of differential hardening behaviour of steels by multi-scale crystal plasticity modelling

    NARCIS (Netherlands)

    Eyckens, P.; Mulder, J.; Gawad, J.; Vegter, H.; Roose, D.; van den Boogaard, Antonius H.; Van Bael, A.; Van Houtte, P.

    2015-01-01

    An essential aspect of materials modelling in the field of metal plasticity is hardening. The classical assumption of isotropic hardening in metal plasticity models is often too simplified to describe actual material behaviour. This paper focuses on the non-isotropic hardening termed differential

  1. OCCUPATIONAL ASTHMA CAUSED BY A HARDENER CONTAINING AN ALIPHATIC AND A CYCLOALIPHATIC DIAMINE

    NARCIS (Netherlands)

    ALEVA, RM; AALBERS, R; KOETER, GH; DEMONCHY, JGR

    An otherwise healthy 44-yr-old man experienced a serious attack of bronchial obstruction after working with resins and hardeners, releasing fumes of a mixture of an aliphatic and a cycloaliphatic diamine hardener. Eight hours after deliberate challenge with the hardener a large increase of airway

  2. Stress Corrosion Cracking Behavior of Hardening-Treated 13Cr Stainless Steel

    Science.gov (United States)

    Niu, Li-Bin; Ishitake, Hisamitsu; Izumi, Sakae; Shiokawa, Kunio; Yamashita, Mitsuo; Sakai, Yoshihiro

    2018-03-01

    Stress corrosion cracking (SCC) behavior of the hardening-treated materials of 13Cr stainless steel was examined with SSRT tests and constant load tests. In the simulated geothermal water and even in the test water without addition of impurities, the hardening-treated materials showed a brittle intergranular fracture due to the sensitization, which was caused by the present hardening-treatments.

  3. Influence of Plastic Deformation on Low Temperature Surface Hardening of Austenitic and Precipitation Hardening Stainless Steels by Gaseous Nitriding

    DEFF Research Database (Denmark)

    Bottoli, Federico; Winther, Grethe; Christiansen, Thomas Lundin

    2015-01-01

    This article addresses an investigation of the influence of plastic deformation on low temperature surface hardening by gaseous nitriding of three commercial austenitic stainless steels: AISI 304, EN 1.4369 and Sandvik Nanoflex® with various degrees of austenite stability. The materials were...

  4. Total dose and dose rate radiation characterization of EPI-CMOS radiation hardened memory and microprocessor devices

    International Nuclear Information System (INIS)

    Gingerich, B.L.; Hermsen, J.M.; Lee, J.C.; Schroeder, J.E.

    1984-01-01

    The process, circuit discription, and total dose radiation characteristics are presented for two second generation hardened 4K EPI-CMOS RAMs and a first generation 80C85 microprocessor. Total dose radiation performance is presented to 10M rad-Si and effects of biasing and operating conditions are discussed. The dose rate sensitivity of the 4K RAMs is also presented along with single event upset (SEU) test data

  5. The Effect of Grain Size on the Strain Hardening Behavior for Extruded ZK61 Magnesium Alloy

    Science.gov (United States)

    Zhang, Lixin; Zhang, Wencong; Chen, Wenzhen; Duan, Junpeng; Wang, Wenke; Wang, Erde

    2017-12-01

    The effects of grain size on the tensile and compressive strain hardening behaviors for extruded ZK61 alloys have been investigated by uniaxial tensile and compressive tests along the extrusion directions. Cylindrical tension and compression specimens of extruded ZK61 alloys with various sized grain were fabricated by annealing treatments. Tensile and compressive tests at ambient temperature were conducted at a strain rate of 0.5 × 10-3 s-1. The results indicate that both tensile strain hardening and compressive strain hardening of ZK61 alloys with different grain sizes have an athermal regime of dislocation accumulation in early deformation. The threshold stress value caused dynamic recovery is predominantly related to grain size in tensile strain hardening, but the threshold stress values for different grain sizes are almost identical in compressive strain hardening. There are obvious transition points on the tensile strain hardening curves which indicate the occurrence of dynamic recrystallization (DRX). The tensile strain hardening rate of the coarse-grained alloy obviously decreases faster than that of fine-grained alloys before DRX and the tensile strain hardening curves of different grain sizes basically tend to parallel after DRX. The compressive strain hardening rate of the fine-grained alloy obviously increases faster than that of coarse-grained alloy for twin-induced strain hardening, but compressive strain hardening curves also tend to parallel after twinning is exhausted.

  6. Strain Hardening and Size Effect in Five-fold Twinned Ag Nanowires.

    Science.gov (United States)

    Narayanan, Sankar; Cheng, Guangming; Zeng, Zhi; Zhu, Yong; Zhu, Ting

    2015-06-10

    Metallic nanowires usually exhibit ultrahigh strength but low tensile ductility owing to their limited strain hardening capability. Here we study the unique strain hardening behavior of the five-fold twinned Ag nanowires by nanomechanical testing and atomistic modeling. In situ tensile tests within a scanning electron microscope revealed strong strain hardening behavior of the five-fold twinned Ag nanowires. Molecular dynamics simulations showed that such strain hardening was critically controlled by twin boundaries and pre-existing defects. Strain hardening was size dependent; thinner nanowires achieved more hardening and higher ductility. The size-dependent strain hardening was found to be caused by the obstruction of surface-nucleated dislocations by twin boundaries. Our work provides mechanistic insights into enhancing the tensile ductility of metallic nanostructures by engineering the internal interfaces and defects.

  7. A tool for Load Modeling in Induction Hardening Equipment Driven by Power Semiconductor Systems

    International Nuclear Information System (INIS)

    Suarez Antola, R.; Suarez Bagnasco, D.

    2006-01-01

    Kelvin effect (Skin effect) is used in surface hardening produced by induction heating of gears, camforms, camshafts and other work pieces of fairly complex geometries.The induction heating equipment for surface hardening of metals and alloys (using LF or medium frequencies in the jargon of induction heating) is composed by a coil or coil assembly and a power semiconductor driving system up to 50kHz. The load seen by the driving system is equivalent to a transformer. The primary corresponds to the excitation coil or coil assembly, and the work piece corresponds to a short-circuited secondary. To asses the electrical load it is necessary to determine the variations in skin depth from place to place due to local curvature effects in the work piece, and its variations in space and time due to variations in conductivity and magnetic properties coupled with thermal effects. In these and others technical applications of Kelvin effect it is often necessary to be able to relate local skin depths with local curvatures of the surface of electrically conductive bodies.The purpose of this paper is twofold. First, derive a closed form analytical formula that relates the local skin depth with the local mean curvature and the well known skin depth for a flat conductive body. The limits of applicability of this formula are discussed. The predicted skin depths are compared with available experimental results obtained in the framework of surface hardening processes. Second, apply the above mentioned formula to describe the electrical load of the induction heating equipment in the conditions used for surface hardening. In the choice or design of an induction heating system the parameters of the intended process (depth of Kelvin effect, temperatures to be reached and duration of the heating process, amongst others) put restrictions over the coils and the power driving system. To determine the best shape and size of induction coils or coil assemblies, the complex thermal and

  8. Segmentation-free empirical beam hardening correction for CT

    Energy Technology Data Exchange (ETDEWEB)

    Schüller, Sören; Sawall, Stefan [German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg 69120 (Germany); Stannigel, Kai; Hülsbusch, Markus; Ulrici, Johannes; Hell, Erich [Sirona Dental Systems GmbH, Fabrikstraße 31, 64625 Bensheim (Germany); Kachelrieß, Marc, E-mail: marc.kachelriess@dkfz.de [German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany)

    2015-02-15

    Purpose: The polychromatic nature of the x-ray beams and their effects on the reconstructed image are often disregarded during standard image reconstruction. This leads to cupping and beam hardening artifacts inside the reconstructed volume. To correct for a general cupping, methods like water precorrection exist. They correct the hardening of the spectrum during the penetration of the measured object only for the major tissue class. In contrast, more complex artifacts like streaks between dense objects need other techniques of correction. If using only the information of one single energy scan, there are two types of corrections. The first one is a physical approach. Thereby, artifacts can be reproduced and corrected within the original reconstruction by using assumptions in a polychromatic forward projector. These assumptions could be the used spectrum, the detector response, the physical attenuation and scatter properties of the intersected materials. A second method is an empirical approach, which does not rely on much prior knowledge. This so-called empirical beam hardening correction (EBHC) and the previously mentioned physical-based technique are both relying on a segmentation of the present tissues inside the patient. The difficulty thereby is that beam hardening by itself, scatter, and other effects, which diminish the image quality also disturb the correct tissue classification and thereby reduce the accuracy of the two known classes of correction techniques. The herein proposed method works similar to the empirical beam hardening correction but does not require a tissue segmentation and therefore shows improvements on image data, which are highly degraded by noise and artifacts. Furthermore, the new algorithm is designed in a way that no additional calibration or parameter fitting is needed. Methods: To overcome the segmentation of tissues, the authors propose a histogram deformation of their primary reconstructed CT image. This step is essential for the

  9. Micromilling of hardened tool steel for mould making applications

    DEFF Research Database (Denmark)

    Bissacco, Giuliano; Hansen, Hans Nørgaard; De Chiffre, Leonardo

    2005-01-01

    The implementation of replication techniques for mass production of micro components relies on the availability of tooling technologies for manufacturing of tools and moulds. Micromilling is a suitable technique for manufacturing of microstructures characterized by high aspect ratios and complex...... geometries as those characterizing injection moulding moulds. The realization of the micromilling process in connection with hardened tool steel as workpiece material is particularly challenging. The low strength of the miniaturized end mills implies reduction and accurate control of the chip load which...... wear. This paper presents the micromilling process applied to the manufacturing of micro injection moulding moulds in hardened tool steel, presenting experimental evidence and possible solutions to the above-mentioned issues....

  10. Radiation effects in semiconductors: technologies for hardened integrated circuits

    International Nuclear Information System (INIS)

    Charlot, J.M.

    1983-09-01

    Various technologies are used to manufacture integrated circuits for electronic systems. But for specific applications, including those with radiation environment, it is necessary to choose an appropriate technologie or to improve a specific one in order to reach a definite hardening level. The aim of this paper is to present the main effects induced by radiation (neutrons and gamma rays) into the basic semiconductor devices, to explain some physical degradation mechanisms and to propose solutions for hardened integrated circuit fabrication. The analysis involves essentially the monolithic structure of the integrated circuits and the isolation technology of active elements. In conclusion, the advantages of EPIC and SOS technologies are described and the potentialities of new technologies (GaAs and SOI) are presented

  11. Radiation effects in semiconductors: technologies for hardened integrated circuits

    International Nuclear Information System (INIS)

    Charlot, J.M.

    1984-01-01

    Various technologies are used to manufacture integrated circuits for electronic systems. But for specific applications, including those with radiation environment, it is necessary to choose an appropriate technology or to improve a specific one in order to reach a definite hardening level. The aim of this paper is to present the main effects induced by radiation (neutrons and gamma rays) into the basic semiconductor devices, to explain some physical degradation mechanisms and to propose solutions for hardened integrated circuit fabrication. The analysis involves essentially the monolithic structure of the integrated circuits and the isolation technology of active elements. In conclusion, the advantages of EPIC and SOS technologies are described and the potentialities of new technologies (GaAs and SOI) are presented. (author)

  12. General Friction Model Extended by the Effect of Strain Hardening

    DEFF Research Database (Denmark)

    Nielsen, Chris V.; Martins, Paulo A.F.; Bay, Niels

    2016-01-01

    An extension to the general friction model proposed by Wanheim and Bay [1] to include the effect of strain hardening is proposed. The friction model relates the friction stress to the fraction of real contact area by a friction factor under steady state sliding. The original model for the real...... contact area as function of the normalized contact pressure is based on slip-line analysis and hence on the assumption of rigid-ideally plastic material behavior. In the present work, a general finite element model is established to, firstly, reproduce the original model under the assumption of rigid......-ideally plastic material, and secondly, to extend the solution by the influence of material strain hardening. This corresponds to adding a new variable and, therefore, a new axis to the general friction model. The resulting model is presented in a combined function suitable for e.g. finite element modeling...

  13. Hardening of cutting tool inserts by ion implantation

    International Nuclear Information System (INIS)

    Zlobin, V.N.; Bannikov, M.G.; Draper, P.H.; Zotov, A.V.

    2001-01-01

    Surface hardening has long been recognized as an important method of increasing the integrity and life of cutting tools. In this work we report preliminary investigations of hardening of conventional hard metal tools by ion implantation Three types of mixed carbide tool inserts were treated by bombardment with 40kV ions of Al, Ti, Zr or W in an ambient of Ar or N/sub 2/, with doses of up to 13*10/sup 17/ ions/cm/sup 2/. The samples were monitored by micro-hardness measurements. Complex behaviors as a function of the implantation dose/time have been observed, and are commented on in terms of the lattice disruption caused by the bombardment. Hardness increments of up to 22 % have been obtained using an ion implanter of industrial size, and cutting tests have shown an improvement, by a factor of three, in the life of these treated tools. (author)

  14. On use of radial evanescence remain term in kinematic hardening

    International Nuclear Information System (INIS)

    Geyer, P.

    1995-01-01

    This paper presents the interest which lies in non-linear kinematic hardening rule with radial evanescence remain term as proposed for modelling multiaxial ratchetting. From analytical calculations in the case of the tension/torsion test, this ratchetting is compared with that proposed by Armstrong and Frederick. A modification is then proposed for Chaboche's elastoplastic model with two non-linear kinematic variables, by coupling the two types of hardening by means of two scalar parameters. Identification of these two parameters returns to speculate on the directions of strain in order to adjust the ratchetting to experimental observations. Using biaxial ratchetting tests on stainless steel 316 L specimens at ambient temperature, it is shown that satisfactory modelling of multiaxial ratchetting is obtained. (author). 4 refs., 5 figs

  15. work hardening, recovery and recrystallization of alloys containing dispersed precipitates

    International Nuclear Information System (INIS)

    Padilha, A.F.

    1989-01-01

    This paper reviews the work hardening, recovery and recrystallization mechanisms in alloys containing dispersed precipitates. In the section on work hardening, the influence od spacing, particle size and shape on the density and distribution of dislocations have been discussed. They represent a large part of the energy stored in the material following drformation, which in turn is driving force for recrystallization. Next, the role of precipitates on recovery, on the formation and the growth of recrystallized regions has been discussed in detail. The competition between recovery and recrystallization and recrystallization of supersaturated solid solutions have also been mentioned. Finally, the technological relevance of the aspects treated in this paper has been discussed. (author) [pt

  16. Study of radiation hardening in reactor pressure vessel steels

    International Nuclear Information System (INIS)

    Nogiwa, Kimihiro; Nishimura, Akihiko

    2008-01-01

    In order to investigate the dependence of hardening on copper precipitate diameter and density, in-situ transmission electron microscopy (TEM) observations during tensile tests of dislocation gliding through copper rich-precipitates in thermally aged and neutron irradiated Fe-Cu alloys were performed. The obstacle strength has been estimated from the critical bow-out angle, φ, of dislocations. The obstacle distance on the dislocation line measured from in-situ TEM observations were compared with number density and diameter measured by 3D-AP (three dimensional atom probe) and TEM observation. A comparison is made between hardening estimation based on the critical bowing angles and those obtained from conventional tensile tests. (author)

  17. Fiber-Reinforced Concrete For Hardened Shelter Construction

    Science.gov (United States)

    1993-02-01

    centuries. Mud bricks reinforced with straw and mortar reinforced with horse hair are but two examples. Engineering properties of natural fibers are...used to reinforce concrete. c. Coir Fibers Coir fibers come from coconut husks. They are easily extracted using water to decompose the soft material...DATES COVERED SFebruary 1993 Final I Oct 91 - 30 Nov 92 4. TITLE AND SUBTITLE S. FUNDING NUMBERS Fiber -Reinforced Concrete for Hardened Shelter

  18. Numerical implementation of a model with directional distortional hardening

    Czech Academy of Sciences Publication Activity Database

    Marek, René; Plešek, Jiří; Hrubý, Zbyněk; Parma, Slavomír; Feigenbaum, H. P.; Dafalias, Y.F.

    2015-01-01

    Roč. 141, č. 12 (2015), 04015048-04015048 ISSN 0733-9399 R&D Projects: GA MŠk LH14018; GA ČR(CZ) GA15-20666S Institutional support: RVO:61388998 Keywords : plasticity * directional distortional hardening * finite-element procedures Subject RIV: JG - Metallurgy Impact factor: 1.346, year: 2015 http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29EM.1943-7889.0000954

  19. Concrete hardened characterization using table scanner and microtomography computed

    International Nuclear Information System (INIS)

    Wilson, R.E.; Pessoa, J.R.; Assis, J.T. de; Dominguez, D.S.; Dias, L.A.; Santana, M. R.

    2016-01-01

    This paper proposes the use of image processing technologies to analyze hardened concrete samples obtained from table scanner and micro tomography. Techniques will be used to obtain numerical data on the distribution and geometry of aggregates and pores of the concrete, as well as their relative position. It is expected that the data obtained can produce information on the research of concrete pathologies such as AAR, and the freeze / thaw process. (author)

  20. Radiation-hardened CMOS/SOS LSI circuits

    International Nuclear Information System (INIS)

    Aubuchon, K.G.; Peterson, H.T.; Shumake, D.P.

    1976-01-01

    The recently developed technology for building radiation-hardened CMOS/SOS devices has now been applied to the fabrication of LSI circuits. This paper describes and presents results on three different circuits: an 8-bit adder/subtractor (Al gate), a 256-bit shift register (Si gate), and a polycode generator (Al gate). The 256-bit shift register shows very little degradation after 1 x 10 6 rads (Si), with an increase from 1.9V to 2.9V in minimum operating voltage, a decrease of about 20% in maximum frequency, and little or no change in quiescent current. The p-channel thresholds increase from -0.9V to -1.3V, while the n-channel thresholds decrease from 1.05 to 0.23V, and the n-channel leakage remains below 1nA/mil. Excellent hardening results were also obtained on the polycode generator circuit. Ten circuits were irradiated to 1 x 10 6 rads (Si), and all continued to function well, with an increase in minimum power supply voltage from 2.85V to 5.85V and an increase in quiescent current by a factor of about 2. Similar hardening results were obtained on the 8-bit adder, with the minimum power supply voltage increasing from 2.2V to 4.6V and the add time increasing from 270 to 350 nsec after 1 x 10 6 rads (Si). These results show that large CMOS/SOS circuits can be hardened to above 1 x 10 6 rads (Si) with either the Si gate or Al gate technology. The paper also discusses the relative advantages of the Si gate versus the Al gate technology

  1. Reduction of metal artifacts: beam hardening and photon starvation effects

    Science.gov (United States)

    Yadava, Girijesh K.; Pal, Debashish; Hsieh, Jiang

    2014-03-01

    The presence of metal-artifacts in CT imaging can obscure relevant anatomy and interfere with disease diagnosis. The cause and occurrence of metal-artifacts are primarily due to beam hardening, scatter, partial volume and photon starvation; however, the contribution to the artifacts from each of them depends on the type of hardware. A comparison of CT images obtained with different metallic hardware in various applications, along with acquisition and reconstruction parameters, helps understand methods for reducing or overcoming such artifacts. In this work, a metal beam hardening correction (BHC) and a projection-completion based metal artifact reduction (MAR) algorithms were developed, and applied on phantom and clinical CT scans with various metallic implants. Stainless-steel and Titanium were used to model and correct for metal beam hardening effect. In the MAR algorithm, the corrupted projection samples are replaced by the combination of original projections and in-painted data obtained by forward projecting a prior image. The data included spine fixation screws, hip-implants, dental-filling, and body extremity fixations, covering range of clinically used metal implants. Comparison of BHC and MAR on different metallic implants was used to characterize dominant source of the artifacts, and conceivable methods to overcome those. Results of the study indicate that beam hardening could be a dominant source of artifact in many spine and extremity fixations, whereas dental and hip implants could be dominant source of photon starvation. The BHC algorithm could significantly improve image quality in CT scans with metallic screws, whereas MAR algorithm could alleviate artifacts in hip-implants and dentalfillings.

  2. Coherent light absorbing by concrete during its hardening

    Science.gov (United States)

    Gorsky, Mykhaylo P.; Maksimyak, Peter P.

    2018-01-01

    In this work changes of concrete reflection coefficient during its hydration were investigated theoretically and experimentally. Diffuse approximation method for concrete light-scattering description during hydration was used and its results were compared with received experimental data. Calculation of scattered and absorption sections for set of particles is described in details. Introduced optical diagnostics method allows performing earlier hydration stages diagnostics of concrete hardening process in comparison with other methods and predicting mechanical properties of produced concrete.

  3. Evaluation of contribution from various hardening mechanisms to yield strength of low- and medium-carbon pearlitic and martensitic steels

    International Nuclear Information System (INIS)

    Sandomirskij, M.M.

    1984-01-01

    Investigation was made into 15Kh2NMFA, 10GN2MFA, 50KhNV, 50KhGSVF, 40Kh5V2FS, 40Kh5M2FS, 40Kh4MVF alloys after hardening and high tempering, as well as after the treatment, simulating the conditions of technological and operational heatings. Pecularities of components of yield strength of low-carbon pearlitic, medium-carbon pearlitic and medium-carbon martensitic steels after hardening and high tempering were considered. Grain-boundary and subgrain-boundary strengthening is the main factor of low-carbon pearlitic steel strengthening. Dislocation structure and carbide phase represent the main factors of medium-carbon pearlitic steel strengthening. Strengthening by uniformly distributed high-dispersion particles is the main factor of medium-carbon martensitic steel strengthening

  4. A study and development of technology for surface induction hardening of railroad rails from low-alloy steel

    Science.gov (United States)

    Degtyarev, S. I.; Skoblo, T. S.; Sapozhnikov, V. E.

    1998-12-01

    A technology of heat treatment of railroad rails using induction heating has been developed and installed in the Azovstal' metallurgical works. It provides the requisite combination of properties in the metal of rail heads. However, the metal of the web and the bottom of the rails remains in the initial (unhardened) state. Under severe operational conditions (small-radius curves, high axial loads, and composite configuration of the road) the wear resistance of the head and the structural strength of the web and the bottom not hardened in the plant have to be increased. The properties of the rail steel can be improved by alloying it using the most effective and available elements. Currently, in Ukraine this is manganese. The present paper is devoted to the effect of manganese additives on the phase transformations in induction hardening and the specific features of the formed structure and properties of the rail steel. Optimum parameters for heat treatment of rails are recommended.

  5. X-Ray diffraction study of strain hardening and annealing in an UNS S31803 duplex stainless steel

    International Nuclear Information System (INIS)

    Aguiar, Denilson Jose Marcolino de; Padilha, Angelo Fernando

    2010-01-01

    In the present work the phenomena of strain hardening, formation and reversion of the strain induced alpha-prime martensite (α', CCC, Ferromagnetic) in an UNS S31803 duplex stainless steel have been studied. Initially, the microstructure of the material in the solution annealed condition was characterized with aid of several complementary techniques of microstructural analysis. The volumetric fraction, crystalline structure, chemical composition, size and morphology of the two phases (ferrite and austenite) have been determined. The phenomena of strain hardening, formation and reversion of strain induced martensite in the austenite phase and recovery of austenite and ferrite phases have been studied, predominantly by using X-ray diffraction and the Rietveld method. (author)

  6. Description of full-range strain hardening behavior of steels.

    Science.gov (United States)

    Li, Tao; Zheng, Jinyang; Chen, Zhiwei

    2016-01-01

    Mathematical expression describing plastic behavior of steels allows the execution of parametric studies for many purposes. Various formulas have been developed to characterize stress strain curves of steels. However, most of those formulas failed to describe accurately the strain hardening behavior of steels in the full range which shows various distinct stages. For this purpose, a new formula is developed based on the well-known Ramberg-Osgood formula to describe the full range strain hardening behavior of steels. Test results of all the six types of steels show a three-stage strain hardening behavior. The proposed formula can describe such behavior accurately in the full range using a single expression. The parameters of the formula can be obtained directly and easily through linear regression analysis. Excellent agreements with the test data are observed for all the steels tested. Furthermore, other formulas such as Ludwigson formula, Gardner formula, UGent formula are also applied for comparison. Finally, the proposed formula is considered to have wide suitability and high accuracy for all the steels tested.

  7. Hardening and welding with high-power diode lasers

    Science.gov (United States)

    Ehlers, Bodo; Herfurth, Hans-Joachim; Heinemann, Stefan

    2000-03-01

    Commercially available high power diode lasers (HPDLs) with output powers of up to 6 kW have been recognized as an interesting tool for industrial applications. In certain fields of application they offer many advantages over Nd:YAG and CO2 lasers because of their low maintenance, compact design and low capital costs. Examples of successful industrial implementation of HPDLs include plastic welding, surface hardening and heat conduction welding of stainless steel and aluminum. The joining of plastics with an HPDL offers the advantages of producing a weld seam with high strength, high consistency and superior appearance. One example is the keyless entry system introduced with the Mercedes E-class where the microelectronic circuits are embedded in a plastic housing. Other applications include instrument panels, cell phones, headlights and tail lights. Applications in the field of surface treatment of metals profit from the HPDL's inherent line-shaped focus and the homogeneous intensity distribution across this focus. An HPDL system is used within the industry to harden rails for coordinate measurement machines. This system contains a customized zoom optic to focus the laser light onto the rails. With the addition of a temperature control, even complex shapes can be hardened with a constant depth and minimum distortion.

  8. Residual stress analysis of drive shafts after induction hardening

    Energy Technology Data Exchange (ETDEWEB)

    Lemos, Guilherme Vieira Braga; Rocha, Alexandre da Silva; Nunes, Rafael Menezes, E-mail: lemos_gl@yahoo.com.br [Universidade Federal do Rio Grande do Sul (UFRS), Porto Algre, RS (Brazil); Hirsch, Thomas Karl [Stiftung Institut für Werkstofftechnik (IWT), Bremen (Germany)

    2014-08-15

    Typically, for automotive shafts, shape distortion manifests itself in most cases after the induction hardening by an effect known as bending. The distortion results in a boost of costs, especially due to machining parts in the hardened state to fabricate its final tolerances. In the present study, residual stress measurements were carried out on automotive drive shafts made of DIN 38B3 steel. The samples were selected in consequence of their different distortion properties by an industrial manufacturing line. One tested shaft was straightened, because of the considerable dimensional variation and the other one not. Firstly, the residual stress measurements were carried out by using a portable diffractometer, in order to avoid cutting the shafts and evaluate the original state of the stresses, and afterwards a more detailed analysis was realized by a conventional stationary diffractometer. The obtained results presented an overview of the surface residual stress profiles after induction hardening and displayed the influence of the straightening process on the redistribution of residual stresses. They also indicated that the effects of the straightening in the residual stresses cannot be neglected. (author)

  9. Recent developments in turning hardened steels - A review

    Science.gov (United States)

    Sivaraman, V.; Prakash, S.

    2017-05-01

    Hard materials ranging from HRC 45 - 68 such as hardened AISI H13, AISI 4340, AISI 52100, D2 STL, D3 STEEL Steel etc., need super hard tool materials to machine. Turning of these hard materials is termed as hard turning. Hard turning makes possible direct machining of the hard materials and also eliminates the lubricant requirement and thus favoring dry machining. Hard turning is a finish turning process and hence conventional grinding is not required. Development of the new advanced super hard tool materials such as ceramic inserts, Cubic Boron Nitride, Polycrystalline Cubic Boron Nitride etc. enabled the turning of these materials. PVD and CVD methods of coating have made easier the production of single and multi layered coated tool inserts. Coatings of TiN, TiAlN, TiC, Al2O3, AlCrN over cemented carbide inserts has lead to the machining of difficult to machine materials. Advancement in the process of hard machining paved way for better surface finish, long tool life, reduced tool wear, cutting force and cutting temperatures. Micro and Nano coated carbide inserts, nanocomposite coated PCBN inserts, micro and nano CBN coated carbide inserts and similar developments have made machining of hardened steels much easier and economical. In this paper, broad literature review on turning of hardened steels including optimizing process parameters, cooling requirements, different tool materials etc., are done.

  10. Importance of calcium and magnesium in water - water hardening

    Science.gov (United States)

    Barloková, D.; Ilavský, J.; Kapusta, O.; Šimko, V.

    2017-10-01

    Basic information about importance of calcium and magnesium in water, about their properties, effect to human health, problems what can cause under the lower ( 5 mmol/L) concentrations in water supply distribution systems, the most commonly used methods of water hardening are presented. The article contains the water hardening results carried out during the pilot plant experiments in WTP Hriňová and WTP Turček. For water hardening, treated water at the end of the process line, i.e., after coagulation, sedimentation and filtration, saturated with CO2 and filtrated through half-burnt dolomite material (PVD) was used. The results show that the filtration rate is 17.1 m/h in the case of WTP Hriňová and 15.2 m/h in the case of WTP Turček to achieve the recommended concentration of Ca and Mg in the treated water after the addition of CO2 and filtration through PVD. The longer the water contact time with PVD (depending on the CO2 content), the more water is enriched with magnesium, but the calcium concentration has not so much increased.

  11. Significance of rate of work hardening in tempered martensite embrittlement

    International Nuclear Information System (INIS)

    Pietikainen, J.

    1995-01-01

    The main explanations for tempered martensite embrittlement are based on the effects of impurities and cementite precipitation on the prior austenite grain boundaries. There are some studies where the rate of work hardening is proposed as a potential reason for the brittleness. One steel was studied by means of a specially developed precision torsional testing device. The test steel had a high Si and Ni content so ε carbide and Fe 3 C appear in quite different tempering temperature ranges. The M S temperature is low enough so that self tempering does not occur. With the testing device it was possible to obtain the true stress - true strain curves to very high deformations. The minimum toughness was always associated with the minimum of rate of work hardening. The change of deformed steel volume before the loss of mechanical stability is proposed as at least one reason for tempered martensite embrittlement. The reasons for the minimum of the rate of work hardening are considered. (orig.)

  12. Radiation-hardened microwave communications system

    International Nuclear Information System (INIS)

    Smith, S.F.; Bible, D.W.; Crutcher, R.I.; Hannah, J.H.; Moore, J.A.; Nowlin, C.H.; Vandermolen, R.I.; Chagnot, D.; LeRoy, A.

    1993-01-01

    To develop a wireless communication system to meet the stringent requirements for a nuclear hot cell and similar environments, including control of advanced servomanipulators, a microwave signal transmission system development program was established to produce a demonstration prototype for the Consolidated Fuel Reprocessing Program at Oak Ridge National Laboratory (ORNL). Proof-of-principle tests in a partially metal lined enclosure at ORNL successfully demonstrated the feasibility of directed microwave signal transmission techniques for remote systems applications. The potential for much more severe radio-frequency (RF) multipath propagation conditions in fully metal lined cells led to a programmatic decision to conduct additional testing in more typical hot-cell environments at other sites. Again, the test results were excellent. Based on the designs of the earlier systems, an advanced microwave signal transmission system configuration was subsequently developed that, in highly reflective environments, will support both high-performance video channels and high baud-rate digital data links at total gamma dose tolerance levels exceeding 10 7 rads and at elevated ambient temperatures

  13. Long-term Effects of Relative Humidity on Properties of Microwave Hardened Moulding Sand with Sodium Silicate

    Directory of Open Access Journals (Sweden)

    Stachowicz M.

    2017-09-01

    Full Text Available Moulding sands containing sodium silicate (water-glass belong to the group of porous mixture with low resistance to increased humidity. Thanks to hydrophilic properties of hardened or even overheated binder, possible is application of effective methods of hydrous reclamation consisting in its secondary hydration. For the same reason (hydrophilia of the binder, moulds and foundry cores made of high-silica moulding sands with sodium silicate are susceptible to the action of components of atmospheric air, including the contained steam. This paper presents results of a research on the effect of (relative humidity on mechanical and technological properties of microwave-hardened moulding mixtures. Specimens of the moulding sand containing 1.5 wt% of sodium water-glass with module 2.5 were subjected, in a laboratory climatic chamber, to long-term action of steam contained in the chamber atmosphere. Concentration of water in atmospheric air was stabilized for 28 days (672 h according to the relative humidity parameter that was ca. 40%, 60% and 80% at constant temperature 20 °C. In three cycles of the examinations, the specimens were taken out from the chamber every 7 days (168 h and their mechanical and technological parameters were determined. It was found on the grounds of laboratory measurements that moulds and cores hardened with microwaves are susceptible to action of atmospheric air and presence of water (as steam intensifies action of the air components on glassy film of sodium silicate. Microwave-hardened moulding sands containing sodium silicate may be stored on a long-term basis in strictly determined atmospheric conditions only, at reduced humidity. In spite of a negative effect of steam contained in the air, the examined moulding mixtures maintain a part of their mechanical and technological properties, so the moulds and foundry cores stored in specified, controlled conditions could be still used in manufacture.

  14. Preparation of in situ hardening composite microcarriers: Calcium phosphate cement combined with alginate for bone regeneration

    Science.gov (United States)

    Park, Jung-Hui; Lee, Eun-Jung; Knowles, Jonathan C

    2014-01-01

    Novel microcarriers consisting of calcium phosphate cement and alginate were prepared for use as three-dimensional scaffolds for the culture and expansion of cells that are effective for bone tissue engineering. The calcium phosphate cement-alginate composite microcarriers were produced by an emulsification of the composite aqueous solutions mixed at varying ratios (calcium phosphate cement powder/alginate solution = 0.8–1.2) in an oil bath and the subsequent in situ hardening of the compositions during spherodization. Moreover, a porous structure could be easily created in the solid microcarriers by soaking the produced microcarriers in water and a subsequent freeze-drying process. Bone mineral-like apatite nanocrystallites were shown to rapidly develop on the calcium phosphate cement–alginate microcarriers under moist conditions due to the conversion of the α-tricalcium phosphate phase in the calcium phosphate cement into a carbonate–hydroxyapatite. Osteoblastic cells cultured on the microspherical scaffolds were proven to be viable, with an active proliferative potential during 14 days of culture, and their osteogenic differentiation was confirmed by the determination of alkaline phosphatase activity. The in situ hardening calcium phosphate cement–alginate microcarriers developed herein may be used as potential three-dimensional scaffolds for cell delivery and tissue engineering of bone. PMID:23836845

  15. Influence of Workpiece Material on Tool Wear Performance and Tribofilm Formation in Machining Hardened Steel

    Directory of Open Access Journals (Sweden)

    Junfeng Yuan

    2016-04-01

    Full Text Available In addition to the bulk properties of a workpiece material, characteristics of the tribofilms formed as a result of workpiece material mass transfer to the friction surface play a significant role in friction control. This is especially true in cutting of hardened materials, where it is very difficult to use liquid based lubricants. To better understand wear performance and the formation of beneficial tribofilms, this study presents an assessment of uncoated mixed alumina ceramic tools (Al2O3+TiC in the turning of two grades of steel, AISI T1 and AISI D2. Both workpiece materials were hardened to 59 HRC then machined under identical cutting conditions. Comprehensive characterization of the resulting wear patterns and the tribofilms formed at the tool/workpiece interface were made using X-ray Photoelectron Spectroscopy and Scanning Electron Microscopy. Metallographic studies on the workpiece material were performed before the machining process and the surface integrity of the machined part was investigated after machining. Tool life was 23% higher when turning D2 than T1. This improvement in cutting tool life and wear behaviour was attributed to a difference in: (1 tribofilm generation on the friction surface and (2 the amount and distribution of carbide phases in the workpiece materials. The results show that wear performance depends both on properties of the workpiece material and characteristics of the tribofilms formed on the friction surface.

  16. Prediction of fresh and hardened properties of self-consolidating concrete using neurofuzzy approach

    Energy Technology Data Exchange (ETDEWEB)

    Sonebi, M.; Cevik, A. [Queens University of Belfast, Belfast (United Kingdom). School for Planning Architecture & Civil Engineering

    2009-11-15

    Self-consolidating concrete (SCC) developed in Japan in the late 80s has enabled the construction industry to reduce demand on the resources, improve the work conditions and also reduce the impact on the environment by elimination of the need for compaction. This investigation aimed at exploring the potential use of the neurofuzzy (NF) approach to model the fresh and hardened properties of SCC containing pulverised fuel ash (PFA) as based on experimental data investigated in this paper. Twenty six mixes were made with water-to-binder ratio ranging from 0.38 to 0.72, cement content ranging from 183 to 317 kg/m{sup 3}, dosage of PFA ranging from 29 to 261 kg/m{sup 3}, and percentage of superplasticizer, by mass of powder, ranging from 0 to 1%. Nine properties of SCC mixes modeled by NF were the slump flow, JRing combined to the Orimet, JRing combined to cone, V-funnel, L-box blocking ratio, segregation ratio, and the compressive strength at 7, 28, and 90 days. These properties characterized the filling ability, the passing ability, the segregation resistance of fresh SCC, and the compressive strength. NF model is constructed by training and testing data using the experimental results obtained in this study. The results of NF models were compared with experimental results and were found to be quite accurate. The proposed NF models offers useful modeling approach of the fresh and hardened properties of SCC containing PFA.

  17. Plasma methods of obtainment of multifunctional composite materials, dispersion-hardened by nanoparticles

    Science.gov (United States)

    Sizonenko, O. N.; Grigoryev, E. G.; Zaichenko, A. D.; Pristash, N. S.; Torpakov, A. S.; Lipyan, Ye V.; Tregub, V. A.; Zholnin, A. G.; Yudin, A. V.; Kovalenko, A. A.

    2016-04-01

    The new approach in developed plasma methods consists in that dispersionhardening additives (TiC, TiB2 in particular) are not mechanically added to powder mixture as additional component, as in conventional methods, but are instead synthesized during high voltage electric discharges (HVED) in disperse system “hydrocarbon liquid - powder” preservation of ultrafine structure is ensured due to use of spark plasma sintering (SPS) as a consolidation method. HVED in disperse system “hydrocarbon liquid - powder” due to impact of plasma discharge channel, electromagnetic fields, shock waves mechanical impact, hydro flows and volume microcavitation leads to synthesis of nanocarbon, metal powders dispersion and synthesis of micro- (from 10-6 to 10-7 m) and nanosized (from 10-7 to 10-9 m) composite powders of hardening phases. SPS is the passage of pulsed current (superposition of direct and alternating current) through powder with the simultaneous mechanical compressing. The formation of plasma is initiated in gaseous phase that fills gaps between particles. SPS allows targeted control of grain growth rate and thus allows obtainment of multifunctional composite materials dispersion hardened by nanoparticles. Processes of HVED synthesis of micro- and nanosized powders of new compositions from elemental metal powders and their mixtures with the subsequent application of high-speed SPS of obtained powders create conditions for increase of strength (by 10 - 20%), hardness and wear-resistance (by 30 - 60%) of obtained materials.

  18. Cyclic loading of thick vessels based on the Prager and Armstrong-Frederick kinematic hardening models

    International Nuclear Information System (INIS)

    Mahbadi, H.; Eslami, M.R.

    2006-01-01

    The aim of this paper is to relate the type of stress category in cyclic loading to ratcheting or shakedown behaviour of the structure. The kinematic hardening theory of plasticity based on the Prager and Armstrong-Frederick models is used to evaluate the cyclic loading behaviour of thick spherical and cylindrical vessels under load and deformation controlled stresses. It is concluded that kinematic hardening based on the Prager model under load and deformation controlled conditions, excluding creep, results in shakedown or reversed plasticity for spherical and cylindrical vessels with the isotropy assumption of the tension/compression curve. Under an anisotropy assumption of the tension/compression curve, this model predicts ratcheting. On the other hand, the Armstrong-Frederick model predicts ratcheting under load controlled cyclic loading and reversed plasticity for deformation controlled stress. The interesting conclusion is that the Armstrong-Frederick model is well capable to predict the experimental data under the assumed type of stresses, wherever experimental data are available

  19. Irradiation hardening in F82H irradiated at 573 K in the HFIR

    Science.gov (United States)

    Hirose, T.; Okubo, N.; Tanigawa, H.; Ando, M.; Sokolov, M. A.; Stoller, R. E.; Odette, G. R.

    2011-10-01

    Post-irradiation tensile tests were conducted on alloy F82H and variants of this steels irradiated at 573 K up to 19 dpa in the High Flux Isotope Reactor (HFIR) in Oak Ridge National Laboratory. Post-irradiation tensile and hardness tests revealed that the strength of F82H steeply increased below 5 dpa, and the total elongation decreased. The ductility of the variants, which showed more ductility in the unirradiated condition was the same as irradiated F82H, even though the magnitude of irradiation hardening is smaller than F82H. This suggests that the softened parts of the blanket, such as heat affected zones, could show more ductility loss at this temperature. The hardening behavior of F82H with 0.09% additional tantalum (mod3), which demonstrated microstructural stability under high temperature processing, was very similar to that of F82H. Therefore mod3 can be an attractive alternate structural material for a blanket when processed above 1373 K.

  20. Effects of Dynamic Strain Hardening Exponent on Abnormal Cleavage Fracture Occurring During Drop Weight Tear Test of API X70 and X80 Linepipe Steels

    Science.gov (United States)

    Kang, Minju; Kim, Hyunmin; Lee, Sunghak; Shin, Sang Yong

    2014-02-01

    In this study, drop weight tear tests (DWTT) were conducted on API X70 and X80 linepipe steels fabricated with various compositions and rolling and cooling conditions in order to correlate the strain hardening with the abnormal cleavage fracture occurring in the hammer-impacted area. Area fractions of fracture modes were measured from fractured DWTT specimens, and the measured data were analyzed in relation to microstructures, Charpy impact energy, and strain hardening. All the steels consisted of fine acicular ferrite, together with some bainitic ferrite, granular bainite, and martensite-austenite constituent. As the volume fraction of acicular ferrite increased, the area fraction of DWTT abnormal cleavage fracture decreased because the toughness of acicular ferrite was higher than other microstructures. The area fraction of abnormal cleavage fracture was weakly related with strain hardening exponents obtained from the quasi-static tensile and compressive tests, but showed better correlation with those obtained from the dynamic compressive test. This tendency could be more clearly observed when steels having similar Charpy impact energy levels were grouped. Since the DWTT was performed under a dynamic loading condition, thus, the abnormal cleavage fracture behavior should be related with the strain hardening analyzed under a dynamic loading condition.

  1. Solution and precipitation hardening of two-phase gamma titanium alloy; Mischkristall- und Ausscheidungshaertung zweiphasiger Gamma-Titanaluminidlegierungen

    Energy Technology Data Exchange (ETDEWEB)

    Christoph, U. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Werkstofforschung

    1997-12-31

    The present study on solution and precipitation hardening of two-phase gamma titanium aluminides was directed towards improved creep resistance. Alloys were systematically doped with carbon up to 0.37 atomic percent. Solid solutions and precipitates of carbon were formed by different thermal treatments. The hardening obtained as a result of the different precipitate conditions was measured by deformation experiments between 293 and 973 K. An increase of yield stress of up to 300 MPa was observed for finely distributed perovskite precipitates. This increase of yield stress was maintained up to 973 K and was shown to be dominantly athermal in character from activation parameter measurements. Electron microscopic investigations confirmed the athermal nature of the perovskite precipitates to dislocation motion. The precipitates thus act as barriers to dislocation glide over a wide temperature range and can therefore increase the creep resistance at the anticipated operation temperature of 973 K. In addition to studying the mechanism of precipitation hardening, the pinning of dislocations by the formation of impurity atmospheres has also been investigated. This phenomenon is effective at intermediate temperatures of around 550 K and is thought to be caused by very mobile elements such as iron and boron. These elements are present in all alloys of technical relevance. (orig.) 158 refs.

  2. Modeling of Work Hardening During Hot Rolling of Vanadium and Niobium Microalloyed Steels in the Low Temperature Austenite Region

    Science.gov (United States)

    Chalimba, Stephen Akonda; Mostert, Roelf; Stumpf, Waldo; Siyasiya, Charles; Banks, Kevin

    2017-11-01

    This work extends the application of the well-established Estrin and Mecking (EM) work-hardening model in unstable low temperature austenite region. The interaction between work hardening, recovery and softening attributed to recrystallization and transformation to ferrite under dynamic conditions is considered. Experimental parameters were varied to study the effects of strain, strain rate and temperature during hot rolling in the low temperature austenite region. Hot compression tests were performed two microalloyed steels—one containing V and the other Nb—at strain rates between 0.1 and 10 s-1 over a temperature range of 750-1000 °C. A model is presented that describes the influence of dynamic recovery on flow behavior in the unstable austenite region. The modified work-hardening model incorporates an additional fitting parameter to the EM model and is dependent on the recovery and softening rates. The new model improved prediction in the unstable austenite region, while the original EM model gave better correlation at relatively higher temperatures when dynamic recrystallization is dominant or at relatively lower temperatures when only dynamic recrystallization to ferrite was the softening mechanism.

  3. Determination of the strain hardening rate of metals and alloys by X ray diffraction

    International Nuclear Information System (INIS)

    Cadalbert, Robert

    1977-01-01

    This report for engineering graduation is based on the study of X ray diffraction line profile which varies with the plastic strain rate of the metal. After some generalities of strain hardening (consequence of a plastic deformation on the structure of a polycrystalline metal, means to study a strain hardened structure, use of X ray diffraction to analyse the strain hardened crystalline structure), the author reports the strain hardening rate measurement by using X ray diffraction. Several aspects are addressed: principles, experimental technique, apparatus, automation and programming of the measurement cycle, method sensitivity and precision. In the next part, the author reports applications: measurement of the strain hardening rate in different materials (tubes with hexagonal profile, cylindrical tubes in austenitic steel), and study of the evolution of strain hardening with temperature [fr

  4. Multi-MGy Radiation Hardened Camera for Nuclear Facilities

    International Nuclear Information System (INIS)

    Girard, Sylvain; Boukenter, Aziz; Ouerdane, Youcef; Goiffon, Vincent; Corbiere, Franck; Rolando, Sebastien; Molina, Romain; Estribeau, Magali; Avon, Barbara; Magnan, Pierre; Paillet, Philippe; Duhamel, Olivier; Gaillardin, Marc; Raine, Melanie

    2015-01-01

    There is an increasing interest in developing cameras for surveillance systems to monitor nuclear facilities or nuclear waste storages. Particularly, for today's and the next generation of nuclear facilities increasing safety requirements consecutive to Fukushima Daiichi's disaster have to be considered. For some applications, radiation tolerance needs to overcome doses in the MGy(SiO 2 ) range whereas the most tolerant commercial or prototypes products based on solid state image sensors withstand doses up to few kGy. The objective of this work is to present the radiation hardening strategy developed by our research groups to enhance the tolerance to ionizing radiations of the various subparts of these imaging systems by working simultaneously at the component and system design levels. Developing radiation-hardened camera implies to combine several radiation-hardening strategies. In our case, we decided not to use the simplest one, the shielding approach. This approach is efficient but limits the camera miniaturization and is not compatible with its future integration in remote-handling or robotic systems. Then, the hardening-by-component strategy appears mandatory to avoid the failure of one of the camera subparts at doses lower than the MGy. Concerning the image sensor itself, the used technology is a CMOS Image Sensor (CIS) designed by ISAE team with custom pixel designs used to mitigate the total ionizing dose (TID) effects that occur well below the MGy range in classical image sensors (e.g. Charge Coupled Devices (CCD), Charge Injection Devices (CID) and classical Active Pixel Sensors (APS)), such as the complete loss of functionality, the dark current increase and the gain drop. We'll present at the conference a comparative study between these radiation-hardened pixel radiation responses with respect to conventional ones, demonstrating the efficiency of the choices made. The targeted strategy to develop the complete radiation hard camera

  5. Multi-MGy Radiation Hardened Camera for Nuclear Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Girard, Sylvain; Boukenter, Aziz; Ouerdane, Youcef [Universite de Saint-Etienne, Lab. Hubert Curien, UMR-CNRS 5516, F-42000 Saint-Etienne (France); Goiffon, Vincent; Corbiere, Franck; Rolando, Sebastien; Molina, Romain; Estribeau, Magali; Avon, Barbara; Magnan, Pierre [ISAE, Universite de Toulouse, F-31055 Toulouse (France); Paillet, Philippe; Duhamel, Olivier; Gaillardin, Marc; Raine, Melanie [CEA, DAM, DIF, F-91297 Arpajon (France)

    2015-07-01

    There is an increasing interest in developing cameras for surveillance systems to monitor nuclear facilities or nuclear waste storages. Particularly, for today's and the next generation of nuclear facilities increasing safety requirements consecutive to Fukushima Daiichi's disaster have to be considered. For some applications, radiation tolerance needs to overcome doses in the MGy(SiO{sub 2}) range whereas the most tolerant commercial or prototypes products based on solid state image sensors withstand doses up to few kGy. The objective of this work is to present the radiation hardening strategy developed by our research groups to enhance the tolerance to ionizing radiations of the various subparts of these imaging systems by working simultaneously at the component and system design levels. Developing radiation-hardened camera implies to combine several radiation-hardening strategies. In our case, we decided not to use the simplest one, the shielding approach. This approach is efficient but limits the camera miniaturization and is not compatible with its future integration in remote-handling or robotic systems. Then, the hardening-by-component strategy appears mandatory to avoid the failure of one of the camera subparts at doses lower than the MGy. Concerning the image sensor itself, the used technology is a CMOS Image Sensor (CIS) designed by ISAE team with custom pixel designs used to mitigate the total ionizing dose (TID) effects that occur well below the MGy range in classical image sensors (e.g. Charge Coupled Devices (CCD), Charge Injection Devices (CID) and classical Active Pixel Sensors (APS)), such as the complete loss of functionality, the dark current increase and the gain drop. We'll present at the conference a comparative study between these radiation-hardened pixel radiation responses with respect to conventional ones, demonstrating the efficiency of the choices made. The targeted strategy to develop the complete radiation hard camera

  6. BUSFET - A Novel Radiation-Hardened SOI Transistor

    International Nuclear Information System (INIS)

    Schwank, J.R.; Shaneyfelt, M.R.; Draper, B.L.; Dodd, P.E.

    1999-01-01

    The total-dose hardness of SOI technology is limited by radiation-induced charge trapping in gate, field, and SOI buried oxides. Charge trapping in the buried oxide can lead to back-channel leakage and makes hardening SOI transistors more challenging than hardening bulk-silicon transistors. Two avenues for hardening the back-channel are (1) to use specially prepared SOI buried oxides that reduce the net amount of trapped positive charge or (2) to design transistors that are less sensitive to the effects of trapped charge in the buried oxide. In this work, we propose a new partially-depleted SOI transistor structure that we call the BUSFET--Body Under Source FET. The BUSFET utilizes a shallow source and a deep drain. As a result, the silicon depletion region at the back channel caused by radiation-induced charge trapping in the buried oxide does not form a conducting path between source and drain. Thus, the BUSFET structure design can significantly reduce radiation-induced back-channel leakage without using specially prepared buried oxides. Total dose hardness is achieved without degrading the intrinsic SEU and dose rate hardness of SOI technology. The effectiveness of the BUSFET structure for reducing total-dose back-channel leakage depends on several variables, including the top silicon film thickness and doping concentration and the depth of the source. 3-D simulations show that for a doping concentration of 10 18 cm -3 and a source depth of 90 nm, a silicon film thickness of 180 nm is sufficient to almost completely eliminate radiation-induced back-channel leakage. However, for a doping concentration of 3x10 17 cm -3 , a thicker silicon film (300 nm) must be used

  7. Precipitation hardening in Fe--Ni base austenitic alloys

    Energy Technology Data Exchange (ETDEWEB)

    Chang, K.M.

    1979-05-01

    The precipitation of metastable Ni/sub 3/X phases in the austenitic Fe--Ni-base alloys has been investigated by using various combinations of hardening elements, including Ti, Ta, Al, and Nb. The theoretical background on the formation of transition precipitates has been summarized based on: atomic size, compressibility, and electron/atom ratio. A model is proposed from an analysis of static concentration waves ordering the fcc lattice. Ordered structure of metastable precipitates will change from the triangularly ordered ..gamma..', to the rectangularly ordered ..gamma..'', as the atomic ratio (Ti + Al)/(Ta + Nb) decreases. The concurrent precipitation of ..gamma..' and ..gamma..'' occurs at 750/sup 0/C when the ratio is between 1.5 and 1.9. Aging behavior was studied over the temperature range of 500/sup 0/C to 900/sup 0/C. Typical hardness curves show a substantial hardening effect due to precipitation. A combination of strength and fracture toughness can be developed by employing double aging techniques. The growth of these coherent intermediate precipitates follows the power law with the aging time t : t/sup 1/3/ for the spherical ..gamma..' particles; and t/sup 1/2/ for the disc-shaped ..gamma..''. The equilibrium ..beta.. phase is observed to be able to nucleate on the surface of imbedded carbides. The addition of 5 wt % Cr to the age-hardened alloys provides a non-magnetic austenite which is stable against the formation of mechanically induced martensite.Cr addition retards aging kinetics of the precipitation reactions, and suppresses intergranular embrittlement caused by the high temperature solution anneal. The aging kinetics are also found to be influenced by solution annealing treatments.

  8. Hardening of electromechanical properties in piezoceramics using a composite approach

    Science.gov (United States)

    K. V., Lalitha; Riemer, Lukas M.; Koruza, Jurij; Rödel, Jürgen

    2017-07-01

    Piezoelectric applications such as ultrasonic motors, transformers and therapeutic ultrasonics demand high power generation with low losses, which is facilitated by "hard" ferroelectrics. Hardening of piezoelectric properties, characterized by high mechanical quality factor (Qm), is usually achieved by doping with lower valence elements, thereby tailoring the domain wall dynamics. In the present study, we demonstrate a hardening mechanism by developing composites of 0.94(Na1/2Bi1/2)TiO3-0.06BaTiO3 (NBT-6BT) with ZnO inclusions, as an alternative to chemical modifications. A decrease in the saturation polarization and total strain, higher internal bias fields, lower hysteretic losses and a two-fold increase in Qm are observed in comparison to NBT-6BT. The composite with 0.1 mole ratio of ZnO exhibits the highest Qm of 320 with d33 = 125 pC/N and Kp = 0.29. A one-to-one correspondence between the increase in Qm and the decrease in the domain wall mobility is established from the ac field dependence of permittivity, in the framework of the Rayleigh law. A further increase in ZnO content beyond a mole ratio of 0.1 reduces Qm, but retains it at a higher level, as compared to NBT-6BT. The results are explained based on the poling-induced strain incompatibility between the matrix and the hard ZnO phase. This composite approach is therefore considered a generic hardening concept and can be extended to other ferroelectric systems.

  9. Increase of resistance to cracking on stress relieving of hardened steel

    International Nuclear Information System (INIS)

    Velichko, V.V.; Zabil'skij, V.V.; Mikheev, G.M.

    1995-01-01

    Regularities of increase of resistance to cracking during stress relieving of hardened low-alloyed steels were studied, using complex of methods. Effect of carbon, stress concentrator radius, duration and temperature of stress relieving was studies in particular. Results of investigating kinetics of change of physicomechanical properties, hydrogen desorption from hardened specimens showed, that increase of resistance to cracking was caused by desorption from grain boundaries of diffusion-mobile hydrogen, formed during hardening. 18 refs., 8 figs

  10. A project of X-ray hardening correction in large ICT

    International Nuclear Information System (INIS)

    Fang Min; Liu Yinong; Ni Jianping

    2005-01-01

    This paper presents a means of polychromatic X-ray beam hardening correction using a standard function to transform the polychromatic projection to monochromatic projection in large Industrial Computed Tomography (ICT). Some parameters were defined to verify the validity of hardening correction in large ICT and optimized. Simulated experiments were used to prove that without prior knowledge of the composition of the scanned object, the correction method using monochromatic reconstruction arithmetic could remove beam hardening artifact greatly. (authors)

  11. The development of radiation hardened robot for nuclear facility

    International Nuclear Information System (INIS)

    Kim, Seung Ho; Jung, Seung Ho; Kim, Byung Soo and others

    2000-04-01

    The work conducted in this stage covers development of core technology of tele-robot system including monitoring technique in high-level radioactive area, tele-sensing technology and radiation-hardened technology for the non-destructive tele-inspection system which monitors the primary coolant system during the normal operations of PHWR(Pressurized Heavy Water Reactor) NPPs and measures the decrease of bending part of feeder pipe during overall. Based on the developed core technology, the monitoring mobile robot system of the primary coolant system and the feeder pipe inspecting robot system are developed

  12. Ferroelectric memories: A possible answer to the hardened nonvolatile question

    International Nuclear Information System (INIS)

    Messenger, G.C.; Coppage, F.N.

    1988-01-01

    Ferroelectric memory cells have been fabricated using a process compatible with semiconductor VLSI (Very Large-Scale Integration) manufacturing techniques which are basically nonvolatile and radiation hard. The memory can be made NDRO (Nondestructive Readout) for strategic systems using several techniques; the most practical is probably a rapid read/restore in combination with EDAC software. This memory can replace plated wire and will have substantial advantages in cost, weight, size, power and speed. It provides a practical cost-competitive solution to the need for nonvolatile RAM in all hardened tactical, avionic, and space systems

  13. The development of radiation hardened robot for nuclear facility

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seung Ho; Jung, Seung Ho; Kim, Byung Soo and others

    2000-04-01

    The work conducted in this stage covers development of core technology of tele-robot system including monitoring technique in high-level radioactive area, tele-sensing technology and radiation-hardened technology for the non-destructive tele-inspection system which monitors the primary coolant system during the normal operations of PHWR(Pressurized Heavy Water Reactor) NPPs and measures the decrease of bending part of feeder pipe during overall. Based on the developed core technology, the monitoring mobile robot system of the primary coolant system and the feeder pipe inspecting robot system are developed.

  14. Disorientations and work-hardening behaviour during severe plastic deformation

    DEFF Research Database (Denmark)

    Pantleon, Wolfgang

    2012-01-01

    Orientation differences develop during plastic deformation even in grains of originally uniform orientation. The evolution of these disorientations is modelled by dislocation dynamics taking into account different storage mechanisms. The predicted average disorientation angles across different...... types of boundaries are in agreement with experimental data for small and moderate plastic strains. At large plastic strains after severe plastic deformation, saturation of the measured average disorientation angle is observed. This saturation is explained as an immediate consequence of the restriction...... pressure torsion, but also rationalizes the work-hardening behaviour at large plastic strains as well as a saturation of the flow stress....

  15. Radiation-Hardened Memristor-based Memory for Extreme Environments, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA space exploration missions require radiation-hardened memory technologies that can survive and operate over a wide temperature range. Memristors...

  16. Physical and Thermodynamical Properties of Water Phases in Hardening Portland Cement Systems

    DEFF Research Database (Denmark)

    Hansen, T. Bæk

    The present study is devoted to the description of water phases in hardening portland cement paste systems containing a significant amount of micro-filler and having a low to moderate water/powder ratio. Emphasis has been placed on the early stages of the hardening process.......The present study is devoted to the description of water phases in hardening portland cement paste systems containing a significant amount of micro-filler and having a low to moderate water/powder ratio. Emphasis has been placed on the early stages of the hardening process....

  17. Radiation-Hardened Memristor-based Memory for Extreme Environments Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA space exploration missions require radiation-hardened memory technologies that can survive and operate over a wide temperature range. Memristors...

  18. Plasticity of Cu nanoparticles: Dislocation-dendrite-induced strain hardening and a limit for displacive plasticity

    Directory of Open Access Journals (Sweden)

    Antti Tolvanen

    2013-03-01

    Full Text Available The plastic behaviour of individual Cu crystallites under nanoextrusion is studied by molecular dynamics simulations. Single-crystal Cu fcc nanoparticles are embedded in a spherical force field mimicking the effect of a contracting carbon shell, inducing pressure on the system in the range of gigapascals. The material is extruded from a hole of 1.1–1.6 nm radius under athermal conditions. Simultaneous nucleation of partial dislocations at the extrusion orifice leads to the formation of dislocation dendrites in the particle causing strain hardening and high flow stress of the material. As the extrusion orifice radius is reduced below 1.3 Å we observe a transition from displacive plasticity to solid-state amorphisation.

  19. Plasticity of Cu nanoparticles: Dislocation-dendrite-induced strain hardening and a limit for displacive plasticity.

    Science.gov (United States)

    Tolvanen, Antti; Albe, Karsten

    2013-01-01

    The plastic behaviour of individual Cu crystallites under nanoextrusion is studied by molecular dynamics simulations. Single-crystal Cu fcc nanoparticles are embedded in a spherical force field mimicking the effect of a contracting carbon shell, inducing pressure on the system in the range of gigapascals. The material is extruded from a hole of 1.1-1.6 nm radius under athermal conditions. Simultaneous nucleation of partial dislocations at the extrusion orifice leads to the formation of dislocation dendrites in the particle causing strain hardening and high flow stress of the material. As the extrusion orifice radius is reduced below 1.3 Å we observe a transition from displacive plasticity to solid-state amorphisation.

  20. Surface fatigue life of CBN and vitreous ground carburized and hardened AISI 9310 spur gears

    Science.gov (United States)

    Townsend, Dennis P.; Patel, P. R.

    1988-01-01

    Spur gear surface endurance tests were conducted to investigate CBN ground AISI 9310 spur gears for use in aircraft applications, to determine their endurance characteristics and to compare the results with the endurance of standard vitreous ground AISI 9310 spur gears. Tests were conducted with VIM-VAR AISI 9310 carburized and hardened gears that were finish ground with either CBN or vitreous grinding methods. Test conditions were an inlet oil temeprature of 320 K (116 F), an outlet oil temperature of 350 K (170 F), a maximum Hertz stress of 1.71 GPa (248 ksi), and a speed of 10,000 rpm. The CBN ground gears exhibited a surface fatigue life that was slightly better than the vitreous ground gears. The subsurface residual stress of the CBN ground gears was approximately the same as that for the standard vitreous ground gears for the CBN grinding method used.

  1. Simplified method for elastic plastic analysis of material presenting bilinear kinematic hardening

    International Nuclear Information System (INIS)

    Roche, R.

    1983-12-01

    A simplified method for elastic plastic analysis is presented. Material behavior is assumed to be elastic plastic with bilinear kinematic hardening. The proposed method give a strain-stress field fullfilling material constitutive equations, equations of equilibrium and continuity conditions. This strain-stress is obtained through two linear computations. The first one is the conventional elastic analysis of the body submitted to the applied load. The second one use tangent matrix (tangent Young's modulus and Poisson's ratio) for the determination of an additional stress due to imposed initial strain. Such a method suits finite elements computer codes, the most useful result being plastic strains resulting from the applied loading (load control or deformation control). Obviously, there is not unique solution, for stress-strain field is not depending only of the applied load, but of the load history. Therefore, less pessimistic solutions can be got by one or two additional linear computations [fr

  2. Origin of honeycombs: Testing the hydraulic and case hardening hypotheses

    Science.gov (United States)

    Bruthans, Jiří; Filippi, Michal; Slavík, Martin; Svobodová, Eliška

    2018-02-01

    Cavernous weathering (cavernous rock decay) is a global phenomenon, which occurs in porous rocks around the world. Although honeycombs and tafoni are considered to be the most common products of this complex process, their origin and evolution are as yet not fully understood. The two commonly assumed formation hypotheses - hydraulic and case hardening - were tested to elucidate the origin of honeycombs on sandstone outcrops in a humid climate. Mechanical and hydraulic properties of the lips (walls between adjacent pits) and backwalls (bottoms of pits) of the honeycombs were determined via a set of established and novel approaches. While the case hardening hypothesis was not supported by the determinations of either tensile strength, drilling resistance or porosity, the hydraulic hypothesis was clearly supported by field measurements and laboratory tests. Fluorescein dye visualization of capillary zone, vapor zone, and evaporation front upon their contact, demonstrated that the evaporation front reaches the honeycomb backwalls under low water flow rate, while the honeycomb lips remain dry. During occasional excessive water flow events, however, the evaporation front may shift to the lips, while the backwalls become moist as a part of the capillary zone. As the zone of evaporation corresponds to the zone of potential salt weathering, it is the spatial distribution of the capillary and vapor zones which dictates whether honeycombs are created or the rock surface is smoothed. A hierarchical model of factors related to the hydraulic field was introduced to obtain better insights into the process of cavernous weathering.

  3. The mechanism of anomalous hardening in transition-metal monoborides.

    Science.gov (United States)

    Liang, Yongcheng; Gao, Zhenbang; Qin, Ping; Gao, Li; Tang, Chun

    2017-07-06

    The quest for novel nanomaterials with unusual functionalities continues to be a central challenge to modern nanoscience. Here we report a surprisingly anomalous hardening behavior exhibited by a class of transition-metal monoborides (TMB). Most remarkable is the occurrence of the intrinsic hardness maximum at the valence-electron concentration (VEC) of about 8 electrons per formula unit (e per f.u.); both lower and higher VECs lead to the decrease of hardness, contrasting with the expected positive correlation between hardness and VEC. Such an unexpected phenomenon originates from the presence of two sorts of bands near the Fermi level that respond oppositely to the movement of dislocations within the metal bilayer. Furthermore, we demonstrate that the hardness is closely related to the formation energy for TMB, which justifies the importance of the thermodynamic stability in designing superhard materials. Our findings not only elucidate the unique mechanism responsible for unusual atom-scale hardening but also open a new avenue towards designing novel multifunctional nanomaterials with the coexistence of high hardness and excellent electrical conductivity.

  4. Dislocation Starvation and Exhaustion Hardening in Mo-alloy Nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Chisholm, Claire [University of California, Berkeley & LBNL; Bei, Hongbin [ORNL; Lowry, M. B. [University of California, Berkeley; Oh, Jason [Hysitron, Inc., MN; Asif, S.A. Syed [Hysitron, Inc., MN; Warren, O. [Hysitron, Inc., MN; Shan, Zhiwei [Xi' an Jiaotong University, China & Hysitron, Inc., MN; George, Easo P [ORNL; Minor, Andrew [University of California, Berkeley & LBNL

    2012-01-01

    The evolution of defects in Mo alloy nanofibers with initial dislocation densities ranging from 0 to 1.6 1014 m2 were studied using an in situ push-to-pull device in conjunction with a nanoindenter in a transmission electron microscope. Digital image correlation was used to determine stress and strain in local areas of deformation. When they had no initial dislocations the Mo alloy nanofibers suffered sudden catastrophic elongation following elastic deformation to ultrahigh stresses. At the other extreme fibers with a high dislocation density underwent sustained homogeneous deformation after yielding at much lower stresses. Between these two extremes nanofibers with intermediate dislocation densities demonstrated a clear exhaustion hardening behavior, where the progressive exhaustion of dislocations and dislocation sources increases the stress required to drive plasticity. This is consistent with the idea that mechanical size effects ( smaller is stronger ) are due to the fact that nanostructures usually have fewer defects that can operate at lower stresses. By monitoring the evolution of stress locally we find that exhaustion hardening causes the stress in the nanofibers to surpass the critical stress predicted for self-multiplication, supporting a plasticity mechanism that has been hypothesized to account for the rapid strain softening observed in nanoscale bcc materials at high stresses.

  5. Electron beam hardening type copper plate printing ink

    International Nuclear Information System (INIS)

    Kawamura, Eiji; Inoue, Mitsuo; Kusaki, Satoichiro

    1989-01-01

    Copper plate printing is the printing method of filling ink in the parts of concave printing elements on a type area, and transferring the ink to a base, and it is the feature that the ink in the printing element parts of a print rises. Copper plate prints show profound feeling, in addition, its effect of preventing forgery is high. This method is generally called engraving printing, and is used frequently for printing various bills and artistic prints. The electron beam irradiation apparatus installed in the laboratory of the Printing Bureau, Ministry of Finance, is an experimental machine of area beam type, and is so constructed as to do batch conveyance and web conveyance. As the ink in printing element parts rises, the offset at the delivery part of a printing machine becomes a problem. Electron beam is superior in its transparency, and can dry instantaneously to the inside of opaque ink. At 200 kV of acceleration voltage, the ink of copper plate prints can be hardened by electron beam irradiation. The dilution monomers as the vehicle for ink were tested for their dilution capability and the effect of electron beam hardening. The problem in the utilization of electron beam is the deterioration of papers, and the counter-measures were tested. (K.I.)

  6. History-dependent coupled growth of creep damage under variable stress conditions

    Science.gov (United States)

    Kawai, M.

    1998-08-01

    A multiaxial constitutive model is presented for the description of the history-dependent inelastic and damage behavior of polycrystalline metallic materials in the high-temperature range under variable loading conditions. A particular emphasis is placed on a new formulation for the history-dependent material degradation which is based on a coupling between hardening and damage. The total damage is given by the sum of damage components which have different history dependence. The associated continuum damage variables are defined through their evolution equations coupled with hardening parameters involved with a kinematic hardening model. The non-classical coupling between hardening and damage is incorporated into the modified kinematic hardening model which has. been developed for describing the complicated hardening and softening behavior under repeated stress changes. Numerical simulations for different material parameters show that the proposed damage-coupled constitutive model can predict an acceleration as well as a deceleration of creep damage growth due to stress variations.

  7. Effect of Li additions on the age hardening response and precipitate microstructures of Mg–2.4Zn–0.16Zr based alloys

    International Nuclear Information System (INIS)

    Mendis, C.L.; Oh-ishi, K.; Ohkubo, T.; Hono, K.

    2012-01-01

    Highlights: ► Enhancement of age hardening response of Mg–2.4Zn–0.2Zr alloy by addition of 2 at% Li. ► The time to reach peak hardness has been reduced to 1/3 by adding Li. ► The enhancement of mechanical properties was attributed to the refinement in the microstructure. - Abstract: The effect of Li additions and microalloying with Ag and Ca on the age hardening of a Mg–2.4Zn–0.16Zr alloy is studied. The addition of Li up to 2 at% enhances the age hardening response. The major precipitates in the peak aged condition at 160 °C are Mg 4 Zn 7 in which Li is preferentially partitioned. Further addition of trace amounts of Ag and Ca enhances the age hardening response. The size, the number density and the morphology of the precipitates are investigated by transmission electron microscopy and three dimensional atom probe to interpret these results.

  8. Influence of Austenitizing Parameters on Mechanical Behavior of Press Hardened Steels

    Science.gov (United States)

    Golem, Lindsay

    Recent increases in the Corporate Average Fuel Economy standard have led to an increased focus on lightweight materials for use in vehicle architectures. In particular, press hardened steels (PHS) have been identified as suitable materials to reduce vehicle mass while maintaining or possibly improving vehicle crash performance. A fundamental understanding of the mechanical behavior of PHS with respect to changes in processing conditions is critical to their proper use. In this work, 22MnB5 Al-Si coated blanks were austenitized at several different times and temperatures to produce a range of prior austenite grain sizes. Mechanical behavior was evaluated using smooth sided tensile testing, double edge notch tensile testing, and free bend testing. Metrics, such as notch tensile strength, notch strength ratio, and notch displacement, which is based on the fracture mechanics parameter crack tip opening displacement, were derived from double edge notch tensile testing to assess material notch sensitivity and toughness as a function of processing conditions. Additionally, bend angle at maximum load, post uniform bending slope, and energy for fracture were measured using free bend testing to provide another means for evaluating mechanical behavior. Increasing the austenitizing temperature and hold time resulted in an increase in the measured prior austenite grain size; however, elevated austenitizing temperatures also increased the thickness of the coating interdiffusion layer. In the coated material, tensile strength decreased with increasing prior austenite grain size for both notched and smooth sided tensile samples, but minimal difference was observed in the strain to failure results. Notch displacement, bend angle at maximum load, and energy for fracture during free bend testing all decreased with increasing prior austenite grain size in the coated PHS and also showed a significant drop in measured behavior for the 1025 °C for 30 minutes austenitizing condition

  9. Disorientations and their role on the work-hardening in stage IV

    DEFF Research Database (Denmark)

    Pantleon, W.

    2005-01-01

    The eect of deformation-induced disorientations on work-hardening of metals is modelled by dislocation dynamics. By incorporating excess dislocations related to disori- entations, Kocks' dislocation model describing stage III hardening is extended to stage IV. Disorientations evolving from purely...

  10. Numerical Simulation of Stresses due to Solid State Transformations : The Simulation of Laser Hardening

    NARCIS (Netherlands)

    Geijselaers, Hubertus J.M.

    2003-01-01

    The properties of many engineeringmaterialsmay be favourablymodified by application of a suitable heat treatment. Examples are precipitation hardening, tempering and annealing. One of the most important treatments is the transformation hardening of steel. Steel is an alloy of iron and carbon. At

  11. MOULDING MIXTURES HARDENING PROCESS BASED ON LIGNIN-BASE SULPHONATE BINDER

    Directory of Open Access Journals (Sweden)

    V. N. Ektova

    2004-01-01

    Full Text Available Hardening of agglutinant sands on lignosulphonate binding agent is the result of two processes: oxidation-reduction in the system lignosulphonate acids — persulfuric natrium in the early stages of hardening and hydration of cement in the latter stages.

  12. An outbreak of contact dermatitis from toluenesulfonamide formaldehyde resin in a nail hardener

    NARCIS (Netherlands)

    de Wit, F. S.; de Groot, A. C.; Weyland, J. W.; Bos, J. D.

    1988-01-01

    8 cases of contact dermatitis from toluenesulfonamide formaldehyde resin in a nail hardener are presented. Most patients had used nail lacquers containing this resin for many years without trouble, but became sensitized to the resin shortly after the introduction of this particular nail hardener. A

  13. Simulation aided hardening of N-channel power MOSFETs to prevent single event burnout

    International Nuclear Information System (INIS)

    Dachs, C.; Palau, J.M.; Bruguier, G.; Gasiot, J.; Roubaud, F.; Tastet, P.; Calvet, M.C.; Calvel, P.

    1995-01-01

    2D MEDICI simulator is used to investigate hardening solutions to single-event burnout (SEB). SEB parametric dependencies such as carrier lifetime reduction, base enlargement, and emitter doping decrease have been verified and a p + plug modification approach for SEB hardening of power MOSFETs is validated with simulations on actual device structures

  14. Method of case hardening depth testing by using multifunctional ultrasonic testing instrument

    International Nuclear Information System (INIS)

    Salchak, Y A; Sednev, D A; Ardashkin, I B; Kroening, M

    2015-01-01

    The paper describes usability of ultrasonic case hardening depth control applying standard instrument of ultrasonic inspections. The ultrasonic method of measuring the depth of the hardened layer is proposed. Experimental series within the specified and multifunctional ultrasonic equipment are performed. The obtained results are compared with the results of a referent method of analysis. (paper)

  15. Experimental study of self-compacted concrete in hardened state

    Science.gov (United States)

    Parra Costa, Carlos Jose

    The main aim of this work is to investigate the hardened behaviour of Self-Compacting Concrete (SCC). Self compacting Concrete is a special concrete that can flow in its gravity and fill in the formwork alone to its self-weight, passing through the bars and congested sections without the need of any internal or external vibration, while maintaining adequate homogeneity. SCC avoids most of the materials defects due to bleeding or segregation. With regard to its composition, SCC consists of the same components as traditional vibrated concrete (TC), but in different proportions. Thus, the high amount of superplasticizer and high powder content have to taken into account. The high workability of SCC does not allow to use traditional methods for measuring the fresh state properties, so new tests has developed (slump-flow, V-funnel, L-box, and others). The properties of the hardened SCC, which depend on the mix design, should be different from traditional concrete. In order to study the possible modifications of SCC hardened state properties, a review of the bibliography was done. The state of art was focused on the mechanical behaviour (compressive strength, tension strength and elastic modulus), on bond strength of reinforcement steel, and on material durability. The experimental program consisted in the production of two types of concretes: Self-Compacting Concrete and Traditional Concrete. Four different dosages was made with three different water/cement ratio and two strength types of Portland cement, in order to cover the ordinary strength used in construction. Based on this study it can be concluded that compressive strength of SCC and TC are similar (the differences are lesser than 10%), whereas the tensile strength of TC are up to 18% higher. The values of elastic modulus of both concrete are similar. On the other hand, in the ultimate state the bond strength of SCC and TC is similar, although SCC shows higher bond stiffness in the serviceability state (initial

  16. Development of Test Method for Simple Shear and Prediction of Hardening Behavior Considering the Branchings Effect

    International Nuclear Information System (INIS)

    Kim, Dongwook; Bang, Sungsik; Kim, Minsoo; Lee, Hyungyil; Kim, Naksoo

    2013-01-01

    In this study we establish a process to predict hardening behavior considering the Branchings effect for zircaloy-4 sheets. When a metal is compressed after tension in forming, the yield strength decreases. For this reason, the Branchings effect should be considered in FE simulations of spring-back. We suggested a suitable specimen size and a method for determining the optimum tightening torque for simple shear tests. Shear stress-strain curves are obtained for five materials. We developed a method to convert the shear load-displacement curve to the effective stress-strain curve with Fea. We simulated the simple shear forward/reverse test using the combined isotropic/kinematic hardening model. We also investigated the change of the load-displacement curve by varying the hardening coefficients. We determined the hardening coefficients so that they follow the hardening behavior of zircaloy-4 in experiments

  17. Development of Test Method for Simple Shear and Prediction of Hardening Behavior Considering the Branchings Effect

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dongwook; Bang, Sungsik; Kim, Minsoo; Lee, Hyungyil; Kim, Naksoo [Sogang Univ., Seoul (Korea, Republic of)

    2013-10-15

    In this study we establish a process to predict hardening behavior considering the Branchings effect for zircaloy-4 sheets. When a metal is compressed after tension in forming, the yield strength decreases. For this reason, the Branchings effect should be considered in FE simulations of spring-back. We suggested a suitable specimen size and a method for determining the optimum tightening torque for simple shear tests. Shear stress-strain curves are obtained for five materials. We developed a method to convert the shear load-displacement curve to the effective stress-strain curve with Fea. We simulated the simple shear forward/reverse test using the combined isotropic/kinematic hardening model. We also investigated the change of the load-displacement curve by varying the hardening coefficients. We determined the hardening coefficients so that they follow the hardening behavior of zircaloy-4 in experiments.

  18. Research on SEU hardening of heterogeneous Dual-Core SoC

    Science.gov (United States)

    Huang, Kun; Hu, Keliu; Deng, Jun; Zhang, Tao

    2017-08-01

    The implementation of Single-Event Upsets (SEU) hardening has various schemes. However, some of them require a lot of human, material and financial resources. This paper proposes an easy scheme on SEU hardening for Heterogeneous Dual-core SoC (HD SoC) which contains three techniques. First, the automatic Triple Modular Redundancy (TMR) technique is adopted to harden the register heaps of the processor and the instruction-fetching module. Second, Hamming codes are used to harden the random access memory (RAM). Last, a software signature technique is applied to check the programs which are running on CPU. The scheme need not to consume additional resources, and has little influence on the performance of CPU. These technologies are very mature, easy to implement and needs low cost. According to the simulation result, the scheme can satisfy the basic demand of SEU-hardening.

  19. A fast beam hardening correction method incorporated in a filtered back-projection based MAP algorithm

    Science.gov (United States)

    Luo, Shouhua; Wu, Huazhen; Sun, Yi; Li, Jing; Li, Guang; Gu, Ning

    2017-03-01

    The beam hardening effect can induce strong artifacts in CT images, which result in severely deteriorated image quality with incorrect intensities (CT numbers). This paper develops an effective and efficient beam hardening correction algorithm incorporated in a filtered back-projection based maximum a posteriori (BHC-FMAP). In the proposed algorithm, the beam hardening effect is modeled and incorporated into the forward-projection of the MAP to suppress beam hardening induced artifacts, and the image update process is performed by Feldkamp-Davis-Kress method based back-projection to speed up the convergence. The proposed BHC-FMAP approach does not require information about the beam spectrum or the material properties, or any additional segmentation operation. The proposed method was qualitatively and quantitatively evaluated using both phantom and animal projection data. The experimental results demonstrate that the BHC-FMAP method can efficiently provide a good correction of beam hardening induced artefacts.

  20. Evaluation of hardening by ion irradiation in molybdenum using nanoindentation techniques

    International Nuclear Information System (INIS)

    Iwakiri, Hirotomi; Watanabe, Hideo; Yoshida, Naoaki

    1997-01-01

    As a part of fundamental research on interaction of plasma and wall, some model experiments on loading of particles such as He, H and so forth suffered by plasma facing material were conducted for Mo in high Z material. As an evaluation method for it, nanoindentation technique was proposed. By this method, the hardness evaluation in surface neighboring damage range was conducted. As a result, in the helium irradiated materials, sufficient hardening was observed even at low dpa range impossible to recognize hardening on heavy ion and deuterium irradiated materials, and extreme hardening was established by formation of helium bubble at high dpa region. Furthermore, in the helium irradiated materials, recovery of hardening could not be observed even for annealed materials at 1173 K for 1 hr after irradiation. From such results, hardening promotion work due to helium and extreme thermal stability of the formed defects were elucidated. (B.K.)

  1. Unit rupture work as a criterion for quantitative estimation of hardenability in steel

    International Nuclear Information System (INIS)

    Kramarov, M.A.; Orlov, E.D.; Rybakov, A.B.

    1980-01-01

    Shown is possible utilization of high sensitivity of resistance to fracture of structural steel to the hardenability degree in the course of hardening to find the quantitative estimation of the latter one. Proposed is a criterion kappa, the ratio of the unit rupture work in the case of incomplete hardenability (asub(Tsub(ih))) under investigation, and the analoguc value obtained in the case of complete hardenability Asub(Tsub(Ch)) at the testing temperature corresponding to the critical temperature Tsub(100(M). Confirmed is high criterion sensitivity of the hardened steel structure on the basis of experimental investigation of the 40Kh, 38KhNM and 38KhNMFA steels after isothermal hold-up at different temperatures, corresponding to production of various products of austenite decomposition

  2. Hardening cookies in web-based systems for better system integrity

    International Nuclear Information System (INIS)

    Mohamad Safuan Sulaiman; Mohd Dzul Aiman Aslan; Saaidi Ismail; Abdul Aziz Mohd Ramli; Abdul Muin Abdul Rahman; Siti Nurbahyah Hamdan; Norlelawati Hashimuddin; Sufian Norazam Mohamed Aris

    2012-01-01

    IT Center (ITC) as technical support and provider for most of web-based systems in Nuclear Malaysia has conducted a study to investigate cookie vulnerability in a system for better integrity. A part of the result has found that cookies in a web-based system in Nuclear Malaysia can be easily manipulated. The main objective of the study is to harden the vulnerability of the cookies. Two levels of security procedures have been used and enforced which consist of 1) Penetration test (Pen Test) 2) Hardening procedure. In one of the system, study has found that 121 attempts threats have been detected after the hardening enforcement from 23 March till 20 September 2012. At this stage, it can be concluded that cookie vulnerability in the system has been hardened and integrity has been assured after the enforcement. This paper describes in detail the penetration and hardening process of cookie vulnerability for better supporting web-based system in Nuclear Malaysia. (author)

  3. Identifying Vulnerabilities and Hardening Attack Graphs for Networked Systems

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Sudip; Vullinati, Anil K.; Halappanavar, Mahantesh; Chatterjee, Samrat

    2016-09-15

    We investigate efficient security control methods for protecting against vulnerabilities in networked systems. A large number of interdependent vulnerabilities typically exist in the computing nodes of a cyber-system; as vulnerabilities get exploited, starting from low level ones, they open up the doors to more critical vulnerabilities. These cannot be understood just by a topological analysis of the network, and we use the attack graph abstraction of Dewri et al. to study these problems. In contrast to earlier approaches based on heuristics and evolutionary algorithms, we study rigorous methods for quantifying the inherent vulnerability and hardening cost for the system. We develop algorithms with provable approximation guarantees, and evaluate them for real and synthetic attack graphs.

  4. A plastic damage model with stress triaxiality-dependent hardening

    International Nuclear Information System (INIS)

    Shen Xinpu; Shen Guoxiao; Zhou Lin

    2005-01-01

    Emphases of this study were placed on the modelling of plastic damage behaviour of prestressed structural concrete, with special attention being paid to the stress-triaxiality dependent plastic hardening law and the corresponding damage evolution law. A definition of stress triaxiality was proposed and introduced in the model presented here. Drucker-Prager -type plasticity was adopted in the formulation of the plastic damage constitutive equations. Numerical validations were performed for the proposed plasticity-based damage model with a driver subroutine developed in this study. The predicted stress-strain behaviour seems reasonably accurate for the uniaxial tension and uniaxial compression compared with the experimental data reported in references. Numerical calculations of compressions under various hydrostatic stress confinements were carried out in order to validate the stress triaxiality dependent properties of the model. (authors)

  5. Quenching and hardening in the transverse quasi-elastic peak

    International Nuclear Information System (INIS)

    Alberico, W.M.; Molinari, A.; Ericson, M.

    1981-09-01

    We study in the RPA framework the response of symmetric, infinite nuclear matter to a spin-isospin sensitive probe with both σ.q and σ.xq couplings. The two responses, similar in the low-q region, differ markedly for moderate momenta (>=1fm -1 ). Indeed, whereas the longitudinal one displays a softening and an enhancement (due to the attractive character of the associated particle-hole force), the transverse response is quenched and hardened with respect to the free Fermi gas. The existing experimental data, which we analyze, are compatible with our results. We also explore the total strengths and find that for repulsive forces they are appreciably reduced by the RPA correlations. Large part of this quenching comes from the Δ excitation (LLEE effect), but some reduction is still present even when the nucleonic degrees of freedom are neglected. This illustrates a violation of strength conservation brougth about by the RPA correlations in the spin-isospin channel

  6. Process for hardening an alkyd resin composition using ionizing radiation

    International Nuclear Information System (INIS)

    Watanabe, Tadashi; Murata, Koichiro; Maruyama, Tsutomu.

    1969-01-01

    In an alkyd resin composition having free hydroxide radicals and containing a conjugated unsaturated fatty acid and/or oil as a component thereof, a process for hardening an alkyd resin composition comprises the steps of dissolving into a vinyl monomer, the product obtained by the semi-esterification reaction of said hydroxide radicals with acid anhydrides having polymerizable radicals and hardening by ionizing radiation to provide a coating with a high degree of cross-linking, with favorable properties such as toughness, hardness, chemical resistance and resistance to weather and with the feasibility of being applied as the ground and finish coat on metals, wood, paper, outdoor construction or the like. Any kind of ionization radiation, particularly accelerated electron beams, γ radiation can be used at 50 0 C to -5 0 C for a few seconds or minutes, permitting continuous operation. In one example, 384 parts of phthalic anhydride, 115 parts of pentaerythritol, 233 parts of trimethylol ethane, 288 parts of tung fatty acid and 49 parts of para-tertiary-butyl benzoic acid are mixed and heated with 60 parts of xylene to an acid value of 12. In addition, 271 parts of maleic anhydride and 0.6 parts of hydroquinone are admixed with the content and heated to terminate the reaction. 100 parts of a 50% stylene solution of this alkyd resin are mixed with 1 part of a 60% toluene solution of cobalt naphthenate, and then coated on a glass plate and irradiated with high energy electron beams of 300 kV with a dose of 5 Mrad for 1 sec. (Iwakiri, K.)

  7. The Effect of Strain Hardening on the Dynamic Response of Human Artery Segments.

    Science.gov (United States)

    Charalambous, Haralambia P; Roussis, Panayiotis C; Giannakopoulos, Antonios E

    2017-01-01

    When subjected to time-dependent blood pressure, human arteries undergo large deformations, exhibiting mainly nonlinear hyperelastic type of response. The mechanical response of arteries depends on the health of tissues that comprise the artery walls. Typically, healthy arteries exhibit convex strain hardening under tensile loads, atherosclerotic parts exhibit stiffer response, and aneurysmatic parts exhibit softening response. In reality, arterial dynamics is the dynamics of a propagating pulse, originating in heart ventricle, propagating along aorta, bifurcating, etc . Artery as a whole cannot be simulated as a lump ring, however its cross section can be simulated as a vibrating ring having a phase lag with respect to the other sections, creating a running pressure wave. A full mathematical model would require fluid-solid interaction modeling continuity of blood flow in a compliant vessel and a momentum equation. On the other hand, laboratory testing often uses small-length arteries, the response of which is covered by the present work. In this way, material properties that change along the artery length can be investigated. The effect of strain hardening on the local dynamic response of human arteries (excluding the full fluid-structure interaction) is examined through appropriate hyperelastic models related to the health condition of the blood vessel. Furthermore, this work aims at constituting a basis for further investigation of the dynamic response of arteries accounting for viscosity. The governing equation of motion is formulated for three different hyperelastic material behaviors, based on the constitutive law proposed by Skalak et al. , Hariton, and Mooney-Rivlin, associated with the hardening behavior of healthy, atherosclerotic, and aneurysmatic arteries, respectively. The differences between these modelling implementations are caused by physiology, since aneurysmatic arteries are softer and often sclerotic arteries are stiffer than healthy arteries

  8. Investigation on microstructural evolution and hardening mechanism in dilute Zr–Nb binary alloys

    Energy Technology Data Exchange (ETDEWEB)

    Yang, H.L., E-mail: yanghuilong@tokai.t.u-tokyo.ac.jp [Department of Nuclear Engineering, Graduate School of Engineering, The University of Tokyo, 2-22 Shirakata Shirane, Tokai, Ibaraki 319-1188 (Japan); Matsukawa, Y. [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Sendai 980-8577 (Japan); Kano, S. [Department of Nuclear Engineering, Graduate School of Engineering, The University of Tokyo, 2-22 Shirakata Shirane, Tokai, Ibaraki 319-1188 (Japan); Duan, Z.G. [Graduate School of Engineering, Tohoku University, 2-1-1 Katahira, Sendai 980-8577 (Japan); Murakami, K. [Department of Nuclear Engineering, Graduate School of Engineering, The University of Tokyo, 2-22 Shirakata Shirane, Tokai, Ibaraki 319-1188 (Japan); Abe, H. [Department of Nuclear Engineering, Graduate School of Engineering, The University of Tokyo, 2-22 Shirakata Shirane, Tokai, Ibaraki 319-1188 (Japan); Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Sendai 980-8577 (Japan)

    2016-12-01

    In this study, the microstructural changes induced by doping of Nb in Zr were investigated by the combined utilization of electron backscatter diffraction and electron transmission microscopy techniques, followed by the correlated hardening mechanism being elucidated based on the obtained microstructural parameters. Microstructural characterization results revealed that microstructural changes caused by doping of Nb in Zr were mainly embodied via two aspects: reducing the matrix α-Zr grain size and increasing the amount of β-Nb particles. β-phase stabilizing effect, dragging effect and pinning effect introduced and enhanced by Nb addition, worked together to significantly reduce the grain size in Zr–Nb alloys. β-Nb particles were firstly observed in Zr0.5Nb specimen with the fairly low number density of ∼2.0 × 10{sup 18}/m{sup 3}, then this value explosively increased to ∼3.3 × 10{sup 20}/m{sup 3} for Zr2Nb specimen. In addition, hardness was increased with an increase in the Nb content. The hardening contributions from solid solution hardening, grain boundary hardening and precipitation hardening were quantitatively estimated as per the obtained microstructural parameters. Results inferred that solid solution hardening contributed the majority when the Nb atoms were solid dissolved (≤0.5 wt%), whereas the precipitation hardening surpassed any other factors when the β-Nb particles were steadily precipitated (≥1 wt%).

  9. HARDENING OF CRANE RAILS BY PLASMA DISCRETE-TIME SURFACE TREATMENT

    Directory of Open Access Journals (Sweden)

    S. S. Samotugin

    2017-01-01

    Full Text Available Crane wheels and rails are subjected to intensive wear in the process of operation. Therefore, improvement of these components’ performance can be considered a task of high importance. A promising direction in this regard is surface treatment by highly concentrated energy flows such as laser beams or plasma jets. This thesis suggests that the use of gradient plasma surface treatment can improve the performance of crane rails. A research was conducted, according to which hardened zones were deposited on crane rails under different treatment modes. Microhardness was measured both at the surface and in depth using custom-made microsections. The article includes the results of study of plasma surface hardening effects on wear resistance of crane rails. Change of plasma surface treatment parameters (current, plasma torch movement speed, argon gas flow rate allows for desired steel hardness and structure, while the choice of optimal location for hardened zones makes it possible to significantly improve wear resistance and crack resistance. As a result of plasma surface hardening, the fine-grained martensite structure is obtained with mainly lamellar morphology and higher hardness rate compared toinduction hardening or overlaying. Wear test of carbon steels revealed that plasma surfacing reduces abrasive wear rate compared to the irinitial state by 2 to 3 times. Enough sharp boundary between hardened and non-hardened portions has a positive effect on the performance of parts under dynamic loads, contributing to the inhibition of cracks during the transition from solid to a soft metal. For carbon and low alloy rail steels, the properties achieved by plasma surface hardening can effectively replace induction hardening or overlaying.The mode range for plasma surface treatment that allow sobtaining a surface layer with certain operating properties has been determined.

  10. Reducing beam hardening effects and metal artefacts using Medipix3RX: With applications from biomaterial science

    CERN Document Server

    Rajendran, K; de Ruiter, N J A; Chernoglazov, A I; Panta, R K; Butler, A P H; Butler, P H; Bell, S T; Anderson, N G; Woodfield, T B F; Tredinnick, S J; Healy, J L; Bateman, C J; Aamir, R; Doesburg, R M N; Renaud, P F; Gieseg, S P; Smithies, D J; Mohr, J L; Mandalika, V B H; Opie, A M T; Cook, N J; Ronaldson, J P; Nik, S J; Atharifard, A; Clyne, M; Bones, P J; Bartneck, C; Grasset, R; Schleich, N; Billinghurst, M

    2014-01-01

    This paper discusses methods for reducing beam hardening effects using spectral data for biomaterial applications. A small-animal spectral scanner operating in the diagnostic energy range was used. We investigate the use of photon-processing features of the Medipix3RX ASIC in reducing beam hardening and associated artefacts. A fully operational charge summing mode was used during the imaging routine. We present spectral data collected for metal alloy samples, its analysis using algebraic 3D reconstruction software and volume visualisation using a custom volume rendering software. Narrow high energy acquisition using the photon-processing detector revealed substantial reduction in beam hardening effects and metal artefacts.

  11. Orowan strengthening and forest hardening superposition examined by dislocation dynamics simulations

    International Nuclear Information System (INIS)

    Queyreau, Sylvain; Monnet, Ghiath; Devincre, Benoit

    2010-01-01

    Rule of mixtures are an essential feature of the modeling of plastic deformation in complex materials in which more than one strain-hardening mechanism is involved. In this work, use is made of dislocation dynamics simulations to characterize the individual and the superposed contributions of two major mechanisms of crystal plasticity, i.e. Orowan strengthening and forest hardening. Based on a formal description of each hardening mechanism, evidence is presented to show that a quadratic rule of mixtures has the ability to predict quantitatively the flow stress of complex materials such as reactor pressure vessel steel.

  12. Studies on Soil Cements : 2 — Physicochemical Properties of the Hardened Soil Cement Pastes.

    OpenAIRE

    Abo El Enein, A. [صلاح عبد الغني ابو العينين; Abdel-Moez, M.S.; Mikhail, R. Sh.; Hekal, E.E.

    1982-01-01

    Various hardened soil-cement pastes were prepared from dry mixtures of montmorillonite clay and portland cement clinker by using different W/C ratios of 0.20, 40, 0.60 and 0.80 and cured in air for various ages. Compressive strength tests were done on the hardened fresh pastes, while the nitrogen adsorption studies were carried out on the D-dried specimens. The variations in compressive strength could be related to the physicochemical properties and the pore structure of the hardened pastes. ...

  13. Progress of the hardening front during core reflooding in a pressurized water nuclear reactor

    International Nuclear Information System (INIS)

    Clement, P.

    1980-01-01

    To study the progress the wetting front during the core reflooding phase in a reactor, the author presents experimental temperature returns obtained on a upright tubular test section simulating a reactor sub-canal, then the sets out a model for heat transfer at the hardening front enabling the experimental axial profile for wall temperatures and speeds of the hardening front to be determined. It likewise enables thermal exchange coefficients obtained in terms of parameters, thermodynamic strength at the hardening front and speed-to-weight ratio of water at the pipe inlet. Overall experiments ought to enable the validity of correlations established to be tested [fr

  14. Nonlinear response to the multiple sine wave excitation of a softening--hardening system

    International Nuclear Information System (INIS)

    Koplik, B.; Subudhi, M.; Curreri, J.

    1979-01-01

    In studying the earthquake response of the HTGR core, it was observed that the system can display softening--hardening characteristics. This is of great consequence in evaluating the structural safety aspects of the core. In order to obtain a better understanding of the governing parameters, an investigation was undertaken with a single-degree-of-freedom system having a softening--hardening spring characteristic and excited by multiple sine waves. A parametric study varying the input amplitudes and the spring characteristic was performed. Transients were introduced into the system, and the jump phenomena between the lower softening characteristics to the higher hardening curve was studied

  15. Some aspects of plasticity in hardened face-centred cubic metals

    International Nuclear Information System (INIS)

    Jackson, P.J.; Nathanson, P.D.K.

    1978-01-01

    The plasticity of crystals of f.c.c. metals hardened by solute atoms, neutron irradiation, quenching and by dislocation distributions not characteristic of the active mode of testing is reviewed, with emphasis being placed on the simiularity of slip after various hardening treatments. Normal work hardening is not treated. The reasons for this exclusion are discussed. It is concluded that correlated slip is a normal aspect of deformation, and that diffuse uncorrelated slip occurs only when secondary dislocation multiplication is promoted, e.g. by obstacles introduced by prior slip, or by the presence of hard impenetrable obstacles of another material or phase [af

  16. Secondary Hardening Behavior in Super Duplex Stainless Steels during LCF in Dynamic Strain Ageing Regime

    OpenAIRE

    Chai, Guocai; Andersson, Marcus

    2013-01-01

    Cyclic deformation behaviors in five modified duplex stainless steel S32705 grades have been studied at 20 °C, 200 °C, 250° and 350 °C. The influence of temperature and nitrogen concentration on the occurrence of the second hardening phenomenon, in the stress response curve was focused. An increase in nitrogen concentration can have a positive effect on dynamic strain ageing by increasing the first hardening and also the second hardening behavior during cyclic deformation. Furthermore, an inc...

  17. DEVELOPMENT AND RESEARCH OF ULTRASONIC OSCILLATORY SYSTEM FOR HARDENING OF SPRING PLATE BILLETS

    Directory of Open Access Journals (Sweden)

    V. A. Tomilo

    2015-01-01

    Full Text Available Various schemes of ultrasonic oscillatory system are developed: with a «force nonsensitive» support, with a «force sensitive» support, with the deforming steel balls in bulk. Results of the ultrasonic treatment showed that hardening of a surface of the samples took place when the vibration amplitude of a radiator exceeds a certain level. The level of hardening increases with increase in amplitude of fluctuations of a radiator. Higher level of hardening is registered when the surface is treated by steel balls.

  18. NINJA: a noninvasive framework for internal computer security hardening

    Science.gov (United States)

    Allen, Thomas G.; Thomson, Steve

    2004-07-01

    Vulnerabilities are a growing problem in both the commercial and government sector. The latest vulnerability information compiled by CERT/CC, for the year ending Dec. 31, 2002 reported 4129 vulnerabilities representing a 100% increase over the 2001 [1] (the 2003 report has not been published at the time of this writing). It doesn"t take long to realize that the growth rate of vulnerabilities greatly exceeds the rate at which the vulnerabilities can be fixed. It also doesn"t take long to realize that our nation"s networks are growing less secure at an accelerating rate. As organizations become aware of vulnerabilities they may initiate efforts to resolve them, but quickly realize that the size of the remediation project is greater than their current resources can handle. In addition, many IT tools that suggest solutions to the problems in reality only address "some" of the vulnerabilities leaving the organization unsecured and back to square one in searching for solutions. This paper proposes an auditing framework called NINJA (acronym for Network Investigation Notification Joint Architecture) for noninvasive daily scanning/auditing based on common security vulnerabilities that repeatedly occur in a network environment. This framework is used for performing regular audits in order to harden an organizations security infrastructure. The framework is based on the results obtained by the Network Security Assessment Team (NSAT) which emulates adversarial computer network operations for US Air Force organizations. Auditing is the most time consuming factor involved in securing an organization's network infrastructure. The framework discussed in this paper uses existing scripting technologies to maintain a security hardened system at a defined level of performance as specified by the computer security audit team. Mobile agents which were under development at the time of this writing are used at a minimum to improve the noninvasiveness of our scans. In general, noninvasive

  19. Exploring visitor acceptability for hardening trails to sustain visitation and minimize impacts

    Science.gov (United States)

    Cahill, K.L.; Marion, J.L.; Lawson, S.R.

    2008-01-01

    Protected natural area managers are challenged to provide high quality recreation opportunities and ensure the protection of resources from impacts associated with visitation. Development of visitor use facilities and application of site hardening practices are commonly applied tools for achieving these competing management objectives. This study applies stated choice analysis to examine visitor opinions on acceptability when they are asked to make tradeoffs among competing social, resource and management attributes in backcountry and frontcountry settings of Acadia National Park. This study demonstrates that asking visitors about recreation setting attributes uni-dimensionally, a common approach, can yield less informative responses. Analyses that considered direct tradeoffs revealed more divergent opinions on acceptability for setting attributes than a unidimensional approach. Findings revealed that visitors to an accessible and popular attraction feature supported trail development options to protect resource conditions with unrestricted visitor access. In contrast, visitors to a remote undeveloped island expressed stronger support for no or limited trail development and access restrictions to protect resource conditions.

  20. Hot deformation characteristics of AZ80 magnesium alloy: Work hardening effect and processing parameter sensitivities

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Y.; Wan, L.; Guo, Z. H.; Sun, C. Y.; Yang, D. J.; Zhang, Q. D.; Li, Y. L.

    2017-02-01

    Isothermal compression experiment of AZ80 magnesium alloy was conducted by Gleeble thermo-mechanical simulator in order to quantitatively investigate the work hardening (WH), strain rate sensitivity (SRS) and temperature sensitivity (TS) during hot processing of magnesium alloys. The WH, SRS and TS were described by Zener-Hollomon parameter (Z) coupling of deformation parameters. The relationships between WH rate and true strain as well as true stress were derived from Kocks-Mecking dislocation model and validated by our measurement data. The slope defined through the linear relationship of WH rate and true stress was only related to the annihilation coefficient Ω. Obvious WH behavior could be exhibited at a higher Z condition. Furthermore, we have identified the correlation between the microstructural evolution including β-Mg17Al12 precipitation and the SRS and TS variations. Intensive dynamic recrystallization and homogeneous distribution of β-Mg17Al12 precipitates resulted in greater SRS coefficient at higher temperature. The deformation heat effect and β-Mg17Al12 precipitate content can be regarded as the major factors determining the TS behavior. At low Z condition, the SRS becomes stronger, in contrast to the variation of TS. The optimum hot processing window was validated based on the established SRS and TS values distribution maps for AZ80 magnesium alloy.

  1. Effects of photoperiodically induced reproductive diapause and cold hardening on the cold tolerance of Drosophila montana.

    Science.gov (United States)

    Vesala, Laura; Hoikkala, Anneli

    2011-01-01

    Coping with seasonal and daily variation in environmental conditions requires that organisms are able to adjust their reproduction and stress tolerance according to environmental conditions. Females of Drosophila montana populations have adapted to survive over the dark and cold winters at high latitudes and altitudes by spending this season in photoperiodically controlled reproductive diapause and reproducing only in spring/summer. The present study showed that flies of a northern population of this species are quite tolerant of low temperatures and show high seasonal and short-term plasticity in this trait. Culturing the flies in short day length (nearly all females in reproductive diapause), as well as allowing the flies to get cold hardened before the cold treatment, increased the cold tolerance of both sexes both in chill coma recovery time test and in mortality assay. Chill coma recovery time test performed for the females of two additional D. montana populations cultured in a day length where about half of the females enter diapause, also showed that diapause can increase female cold tolerance even without a change in day length. Direct linkage between diapause and cold tolerance was found in only two strains representing a high-altitude population of the species, but the phenomenon will certainly be worth of studying in northern and southern populations of the species with larger data sets. 2010 Elsevier Ltd. All rights reserved.

  2. Characterization of the work hardening structure of austenitic steels by X-ray diffraction. Application to the determination of work hardening gradients and the study of recovery

    International Nuclear Information System (INIS)

    Cadalbert, Robert; Baron, J.L.

    1977-01-01

    A method has been developed to determine quantitatively the work hardening of austenitic steels by measurement of the broadening of X-ray diffraction lines. This simple, rapid, accurate and sensible method enables to determine work hardening variations in the thickness of a material. The complete automation of the measurement cycle using a small computer enables to carry out numerous determinations and to process data with accuracy. The unit developed is well adapted to the testing of metallic materials. It is also possible with this method to study the evolution of work hardening in a metal as a function of heat treatments. For instance, the determination of the recovery curves of the crystal lattice in austenitic steels allows to investigate the influence of additions (Mo, Ti) on the recovery kinetics [fr

  3. Designing Security-Hardened Microkernels For Field Devices

    Science.gov (United States)

    Hieb, Jeffrey; Graham, James

    Distributed control systems (DCSs) play an essential role in the operation of critical infrastructures. Perimeter field devices are important DCS components that measure physical process parameters and perform control actions. Modern field devices are vulnerable to cyber attacks due to their increased adoption of commodity technologies and that fact that control networks are no longer isolated. This paper describes an approach for creating security-hardened field devices using operating system microkernels that isolate vital field device operations from untrusted network-accessible applications. The approach, which is influenced by the MILS and Nizza architectures, is implemented in a prototype field device. Whereas, previous microkernel-based implementations have been plagued by poor inter-process communication (IPC) performance, the prototype exhibits an average IPC overhead for protected device calls of 64.59 μs. The overall performance of field devices is influenced by several factors; nevertheless, the observed IPC overhead is low enough to encourage the continued development of the prototype.

  4. Aqueous electrochemistry of precipitation-hardened nickel base alloys

    International Nuclear Information System (INIS)

    Hosoya, K.; Ballinger, R.; Prybylowski, J.; Hwang, I.S.

    1990-11-01

    An investigation has been conducted to explore the importance of local crack tip electrochemical processes in precipitation-hardened Ni-Cr-Fe alloys driven by galvanic couples between grain boundary precipitates and the local matrix. The electrochemical behavior of γ' [Ni 3 (Al,Ti)] has been determined as a function of titanium concentration, temperature, and solution pH. The electrochemical behavior of Ni-Cr-Fe solid solution alloys has been investigated as a function of chromium content for a series of 10 Fe-variable Cr (6--18%)-balance Ni alloys, temperature, and pH. The investigation was conducted in neutral and pH3 solutions over the temperature range 25--300 degree C. The results of the investigation show that the electrochemical behavior of these systems is a strong function of temperature and composition. This is especially true for the γ' [Ni 3 (Al,Ti)] system where a transition from active/passive behavior to purely active behavior and back again occurs over a narrow temperature range near 100 degree C. Behavior of this system was also found to be a strong function of titanium concentration. In all cases, the Ni 3 (Al,Ti) phase was active with respect to the matrix. The peak in activity near 100 degree C correlates well with accelerated crack growth in this temperature range, observed in nickel-base alloy X-750 heat treated to precipitate γ' on the grain boundaries. 20 refs., 23 figs., 3 tabs

  5. Precipitation hardened nickel-base alloys for sour gas environments

    International Nuclear Information System (INIS)

    Igarashi, M.; Mukai, S.; Kudo, T.; Okada, Y.; Ikeda, A.

    1987-01-01

    SCC (Stress Corrosion Cracking) in sour gas environments of γ'(gamma prime: Ni/sub 3/(Ti and/or Al)) and γ''(gamma double prime: Ni/sub 3/Nb) precipitation hardened nickel-base alloys has been studied using the SSRT (Slow Strain Rate Tensile) test, anodic polarization measurement and transmission electron microscopy (TEM). The γ'-type alloy containing Ti was more susceptible to SCC in the SSRT tests up to 350 0 F(450 K) than the γ''-type alloy containing Nb. The susceptibility to SCC was related to their deformation structures in terms of stress localization and sensitivity to pitting corrosion in H/sub 2/S solutions. TEM observation showed the γ'-type alloy deformed by the superlattice dislocations in coplanar structures. This mode of deformation induced the stress localization to some boundaries such as grain boundary and as a result the susceptibility to SCC of the γ'-type alloy was increased. On the other hand, the γ''-type alloy deformed by the massive dislocation not in coplanar structures so that it was less susceptible to SCC in terms of the stress localization. The anodic polarization measurement suggested the γ'-type alloy was more susceptible to pitting corrosion compared with the γ''-type alloy

  6. A Radiation Hardened by Design CMOS ASIC for Thermopile Readouts

    Science.gov (United States)

    Quilligan, G.; Aslam, S.; DuMonthier, J.

    2012-01-01

    A radiation hardened by design (RHBD) mixed-signal application specific integrated circuit (ASIC) has been designed for a thermopile readout for operation in the harsh Jovian orbital environment. The multi-channel digitizer (MCD) ASIC includes 18 low noise amplifier channels which have tunable gain/filtering coefficients, a 16-bit sigma-delta analog-digital converter (SDADC) and an on-chip controller. The 18 channels, SDADC and controller were designed to operate with immunity to single event latchup (SEL) and to at least 10 Mrad total ionizing dose (TID). The ASIC also contains a radiation tolerant 16-bit 20 MHz Nyquist ADC for general purpose instrumentation digitizer needs. The ASIC is currently undergoing fabrication in a commercial 180 nm CMOS process. Although this ASIC was designed specifically for the harsh radiation environment of the NASA led JEO mission it is suitable for integration into instrumentation payloads 011 the ESA JUICE mission where the radiation hardness requirements are slightly less stringent.

  7. Superconducting (radiation hardened) magnets for mirror fusion devices

    International Nuclear Information System (INIS)

    Henning, C.D.; Dalder, E.N.C.; Miller, J.R.; Perkins, J.R.

    1983-01-01

    Superconducting magnets for mirror fusion have evolved considerably since the Baseball II magnet in 1970. Recently, the Mirror Fusion Test Facility (MFTF-B) yin-yang has been tested to a full field of 7.7 T with radial dimensions representative of a full scale reactor. Now the emphasis has turned to the manufacture of very high field solenoids (choke coils) that are placed between the tandem mirror central cell and the yin-yang anchor-plug set. For MFTF-B the choke coil field reaches 12 T, while in future devices like the MFTF-Upgrade, Fusion Power Demonstration and Mirror Advanced Reactor Study (MARS) reactor the fields are doubled. Besides developing high fields, the magnets must be radiation hardened. Otherwise, thick neutron shields increase the magnet size to an unacceptable weight and cost. Neutron fluences in superconducting magnets must be increased by an order of magnitude or more. Insulators must withstand 10 10 to 10 11 rads, while magnet stability must be retained after the copper has been exposed to fluence above 10 19 neutrons/cm 2

  8. Beam hardening correction in CT myocardial perfusion measurement

    Science.gov (United States)

    So, Aaron; Hsieh, Jiang; Li, Jian-Ying; Lee, Ting-Yim

    2009-05-01

    This paper presents a method for correcting beam hardening (BH) in cardiac CT perfusion imaging. The proposed algorithm works with reconstructed images instead of projection data. It applies thresholds to separate low (soft tissue) and high (bone and contrast) attenuating material in a CT image. The BH error in each projection is estimated by a polynomial function of the forward projection of the segmented image. The error image is reconstructed by back-projection of the estimated errors. A BH-corrected image is then obtained by subtracting a scaled error image from the original image. Phantoms were designed to simulate the BH artifacts encountered in cardiac CT perfusion studies of humans and animals that are most commonly used in cardiac research. These phantoms were used to investigate whether BH artifacts can be reduced with our approach and to determine the optimal settings, which depend upon the anatomy of the scanned subject, of the correction algorithm for patient and animal studies. The correction algorithm was also applied to correct BH in a clinical study to further demonstrate the effectiveness of our technique.

  9. Radiation Hardened, Modulator ASIC for High Data Rate Communications

    Science.gov (United States)

    McCallister, Ron; Putnam, Robert; Andro, Monty; Fujikawa, Gene

    2000-01-01

    Satellite-based telecommunication services are challenged by the need to generate down-link power levels adequate to support high quality (BER approx. equals 10(exp 12)) links required for modem broadband data services. Bandwidth-efficient Nyquist signaling, using low values of excess bandwidth (alpha), can exhibit large peak-to-average-power ratio (PAPR) values. High PAPR values necessitate high-power amplifier (HPA) backoff greater than the PAPR, resulting in unacceptably low HPA efficiency. Given the high cost of on-board prime power, this inefficiency represents both an economical burden, and a constraint on the rates and quality of data services supportable from satellite platforms. Constant-envelope signals offer improved power-efficiency, but only by imposing a severe bandwidth-efficiency penalty. This paper describes a radiation- hardened modulator which can improve satellite-based broadband data services by combining the bandwidth-efficiency of low-alpha Nyquist signals with high power-efficiency (negligible HPA backoff).

  10. Critical issues in radiation hardening of fusion diagnostic systems

    International Nuclear Information System (INIS)

    Baur, J.F.; Barker, R.A.; Engholm, B.A.; Miller, P.H.

    1983-01-01

    In the most recent phase of the DOE funded program in Radiation Hardening of Fusion Reactor Diagnostics, a study and listing have been completed of the critical issues. With this information a long range program plan-including system studies, data surveys and a sponsored experimental program-is being developed for integration into the DOE Fusion Engineering Development Plan. More than twenty critical issues were identified, ranked in terms of three parameters (priority, urgency and impact) and described in terms of the remaining research needed. In addition to the critical issues list, three studies that were completed to assess the impact of some of the critical issues are described here briefly. A Survey was conducted of detectors and transducers expected to be impaired by doserate effects in the fusion environment. A set of Monte Carlo computer calculations of the streaming of neutrons through small, diagnostic-sized penetrations in a blanket-shield structure showed that simple analytic expressions for such streaming are inadequate for even preliminary designs of radiationsensitive diagnostic systems. Tests on radiation-darkened window blanks of quartz and sapphire showed that transmission in the ultraviolet region was improved by annealing at 300 0 C, indicating that it may be feasible to include windows in a well-designed viewing system in a reactor

  11. Design of rapid hardening engineered cementitious composites for sustainable construction

    Directory of Open Access Journals (Sweden)

    Marushchak Uliana

    2017-12-01

    Full Text Available This paper deals with design of environmentally friendly Rapid Hardening Engineered Cementitious Composite (RHECC nanomodified with ultrafine mineral additives, polycarboxylate ether based superplasticizer, calcium hydrosilicate nanoparticles and dispersal reinforced by fibers. The incremental coefficient of surface activity was proposed in order to estimation of ultrafine supplementary materials (fly ash, methakaolin, microsilica efficiency. A characterization of RHECC’s compressive and flexural properties at different ages is reported in this paper. Early compressive strength of ECC is 45-50 MPa, standard strength – 84-95 MPa and parameter Rc2/Rc28 – 65–70%. The microstructure of the cement matrix and RHECC was investigated. The use of ultrafine mineral supplementary materials provides reinforcement of structure on micro- and nanoscale level (cementing matrix due to formation of sub-microreinforcing hydrate phase as AFt- and C-S-H phases in unclinker part of cement matrix, resulting in the phenomena of “self-reinforcement” on the microstructure level. Designed RHECC may be regarded as lower brittle since the crack resistance coefficient is higher comparison to conventional fine grain concrete.

  12. Design of rapid hardening engineered cementitious composites for sustainable construction

    Science.gov (United States)

    Marushchak, Uliana; Sanytsky, Myroslav; Sydor, Nazar

    2017-12-01

    This paper deals with design of environmentally friendly Rapid Hardening Engineered Cementitious Composite (RHECC) nanomodified with ultrafine mineral additives, polycarboxylate ether based superplasticizer, calcium hydrosilicate nanoparticles and dispersal reinforced by fibers. The incremental coefficient of surface activity was proposed in order to estimation of ultrafine supplementary materials (fly ash, methakaolin, microsilica) efficiency. A characterization of RHECC's compressive and flexural properties at different ages is reported in this paper. Early compressive strength of ECC is 45-50 MPa, standard strength - 84-95 MPa and parameter Rc2/Rc28 - 65-70%. The microstructure of the cement matrix and RHECC was investigated. The use of ultrafine mineral supplementary materials provides reinforcement of structure on micro- and nanoscale level (cementing matrix) due to formation of sub-microreinforcing hydrate phase as AFt- and C-S-H phases in unclinker part of cement matrix, resulting in the phenomena of "self-reinforcement" on the microstructure level. Designed RHECC may be regarded as lower brittle since the crack resistance coefficient is higher comparison to conventional fine grain concrete.

  13. Hardening of eucalyptus seedlings via salicylic acid application

    Directory of Open Access Journals (Sweden)

    Eduardo Henrique Lima Mazzuchelli

    2014-09-01

    Full Text Available The agricultural and forest productivity suffer restrictions imposed by water stress, high temperature and high solar radiation. This study aimed to evaluate the capacity of stress attenuation and growth promotion of salicylic acid (SA application in eucalyptus (E. urophylla x E. grandis hybrid seedlings under water stress. A completely randomized design, in a 3x4 factorial scheme (three water treatments: constant irrigation with daily replacement of 40% (CI40% or 100% (CI100% of evapotranspirated water, and temporary irrigation suspension with replacement of only 40% of evapotranspirated water (S40%; and four SA concentrations: 0 mg L-1, 100 mg L-1, 200 mg L-1 and 300 mg L-1, was used. Plant photosynthetic parameters and biometric features were evaluated. The stomatal limitation was higher in plants under S40% irrigation, however, the SA application reverted this result, allowing the maintenance of the photosynthetic potential. There was interaction between irrigation regimes and SA doses for number of leaves, leaf area/number of leaves ratio and shoot and root dry mass. It was concluded that the application of 200 mg L -1 of SA positively affected the growth of eucalyptus seedlings under water stress, being considered an auxiliary management technique to their hardening process.

  14. Model Identification and FE Simulations: Effect of Different Yield Loci and Hardening Laws in Sheet Forming

    International Nuclear Information System (INIS)

    Flores, P.; Lelotte, T.; Bouffioux, C.; El Houdaigui, F.; Habraken, A.M.; Duchene, L.; Bael, A. van; He, S.; Duflou, J.

    2005-01-01

    The bi-axial experimental equipment developed by Flores enables to perform Baushinger shear tests and successive or simultaneous simple shear tests and plane-strain tests. Such experiments and classical tensile tests investigate the material behavior in order to identify the yield locus and the hardening models. With tests performed on two steel grades, the methods applied to identify classical yield surfaces such as Hill or Hosford ones as well as isotropic Swift type hardening or kinematic Armstrong-Frederick hardening models are explained. Comparison with the Taylor-Bishop-Hill yield locus is also provided. The effect of both yield locus and hardening model choice will be presented for two applications: Single Point Incremental Forming (SPIF) and a cup deep drawing

  15. Model Identification and FE Simulations: Effect of Different Yield Loci and Hardening Laws in Sheet Forming

    Science.gov (United States)

    Flores, P.; Duchêne, L.; Lelotte, T.; Bouffioux, C.; El Houdaigui, F.; Van Bael, A.; He, S.; Duflou, J.; Habraken, A. M.

    2005-08-01

    The bi-axial experimental equipment developed by Flores enables to perform Baushinger shear tests and successive or simultaneous simple shear tests and plane-strain tests. Such experiments and classical tensile tests investigate the material behavior in order to identify the yield locus and the hardening models. With tests performed on two steel grades, the methods applied to identify classical yield surfaces such as Hill or Hosford ones as well as isotropic Swift type hardening or kinematic Armstrong-Frederick hardening models are explained. Comparison with the Taylor-Bishop-Hill yield locus is also provided. The effect of both yield locus and hardening model choice will be presented for two applications: Single Point Incremental Forming (SPIF) and a cup deep drawing.

  16. A 45 nm Low Cost, Radiation Hardened, Platform Based Structured ASIC Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed 45 nm radiation hardened platform based structured ASIC architecture offers the performance and density expected of a custom ASIC with the low...

  17. Radiation-Hardened, Substrate-Removed, Metamorphic InGaAs Detector Arrays, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — High-performance radiation-hardened metamorphic InGaAs imaging arrays sensitive from the ultraviolet (UV) through the short-wavelength infrared (SWIR) will be...

  18. Radiation Hardened Nanobridge based Non-volatile Memory for Space Applications, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This NASA Phase I SBIR program would develop and demonstrate radiation hardened nanobridge based non-volatile memory (NVM) for space applications. Specifically, we...

  19. Nanoparticle amount, and not size, determines chain alignment and nonlinear hardening in polymer nanocomposites

    Science.gov (United States)

    Varol, H. Samet; Meng, Fanlong; Hosseinkhani, Babak; Malm, Christian; Bonn, Daniel; Bonn, Mischa; Zaccone, Alessio

    2017-01-01

    Polymer nanocomposites—materials in which a polymer matrix is blended with nanoparticles (or fillers)—strengthen under sufficiently large strains. Such strain hardening is critical to their function, especially for materials that bear large cyclic loads such as car tires or bearing sealants. Although the reinforcement (i.e., the increase in the linear elasticity) by the addition of filler particles is phenomenologically understood, considerably less is known about strain hardening (the nonlinear elasticity). Here, we elucidate the molecular origin of strain hardening using uniaxial tensile loading, microspectroscopy of polymer chain alignment, and theory. The strain-hardening behavior and chain alignment are found to depend on the volume fraction, but not on the size of nanofillers. This contrasts with reinforcement, which depends on both volume fraction and size of nanofillers, potentially allowing linear and nonlinear elasticity of nanocomposites to be tuned independently. PMID:28377517

  20. Stage IV work-hardening related to disorientations in dislocation structures

    DEFF Research Database (Denmark)

    Pantleon, W.

    2004-01-01

    The effect of deformation-induced disorientations on the work-hardening of metals is modelled based on dislocation dynamics. Essentially, Kocks’ dislocation model describing stage III hardening is extended to stage IV by incorporation of excess dislocations related to the disorientations....... Disorientations evolving from purely statistical reasons — leading to a square root dependence of the average disorientation angle on strain — affect the initial work-hardening rate (and the saturation stress) of stage III only slightly. On the other hand, deterministic contributions to the development...... of disorientations, as differences in the activated slip systems across boundaries, cause a linear increase of the flow stress at large strains. Such a constant work-hardening rate is characteristic for stage IV....

  1. PERSPECTIVE TECHNOLOGIES OF THERMAL HARDENING OF LARGE-SIZE ARTICLES OF TWO-PHASE TITANIUM ALLOYS

    Directory of Open Access Journals (Sweden)

    V. N. Fedulov

    2005-01-01

    Full Text Available The article is dedicated to the development and industrial assimilation of the fundamentally new methods of thermal strengthening of large articles out of hardenable titanic alloys.

  2. Induction hardening of tool steel for heavily loaded aircraft engine components

    Directory of Open Access Journals (Sweden)

    Rokicki P.

    2017-03-01

    Full Text Available Induction hardening is an innovative process allowing modification of the materials surface with more effective, cheaper and more reproducible way to compare with conventional hardening methods used in the aerospace industry. Unfortunately, high requirements and strict regulation concerning this branch of the industry force deep research allowing to obtain results that would be used for numerical modelling of the process. Only by this way one is able to start the industrial application of the process. The main scope of presented paper are results concerning investigation of microstructure evolution of tool steel after single-frequency induction hardening process. The specimens that aim in representing final industrial products (as heavily loaded gears, were heat- -treated with induction method and subjected to metallographic preparation, after which complex microstructure investigation was performed. The results obtained within the research will be a basis for numerical modelling of the process of induction hardening with potential to be introduced for the aviation industrial components.

  3. Pulsed-laser capabilities at the Laser-Hardened Materials Evaluation Laboratory (LHMEL)

    Science.gov (United States)

    Royse, Robert W.; Seibert, Daniel B., II; Lander, Michael L.; Eric, John J.

    2000-08-01

    Pulsed laser capabilities at the Laser Hardened Material Evaluation Laboratory are described relevant to optical coupling, impulse generation and laser propulsion. Capabilities of the Nd:Glass laser are presented as well as supporting test systems.

  4. The Use of Fuzzy Systems for Forecasting the Hardenability of Steel

    Directory of Open Access Journals (Sweden)

    Sitek W.

    2016-06-01

    Full Text Available The goal of the research carried out was to develop the fuzzy systems, allowing the determination of the Jominy hardenability curve based on the chemical composition of structural steels for quenching and tempering. Fuzzy system was created to calculate hardness of the steel, based on the alloying elements concentrations, and to forecast the hardenability curves. This was done based on information from the PN-EN 10083-3: 2008. Examples of hardenability curves calculated for exemplar steels were presented. Results of the research confirmed that fuzzy systems are a useful tool in evaluation the effect of alloying elements on the properties of materials compared to conventional methods. It has been demonstrated the practical usefulness of the developed models which allows forecasting the steels’ Jominy hardenability curve.

  5. Influence of the Hardener Proportion on Mechanical Properties of Adhesive Bonds Used in Agriculture

    Directory of Open Access Journals (Sweden)

    Valášek P.

    2015-01-01

    Full Text Available Joining materials by adhesive bonding is used across all industrial branches. The occurrence of adhesive bonds in machine constructions is still more frequent because of the development of adhesives which are able to meet various requirements of designers. This trend is observable also in agriculture - in the construction of agricultural machines. There even exists a cooperation between the companies developing the adhesives and the agricultural machines producers. The production process of machines and equipment must consider a required production tact. Adhesives and the process of their hardening have to meet these requirements. In the sphere of agriculture, epoxy resins hardening based either on hardeners or heating are used. Mechanical properties of two-component epoxy resins depending on variable amount of the hardener starting crosslinking of these reactoplastics are described.

  6. Contributions of Cu-rich clusters, dislocation loops and nanovoids to the irradiation-induced hardening of Cu-bearing low-Ni reactor pressure vessel steels

    Energy Technology Data Exchange (ETDEWEB)

    Bergner, F., E-mail: f.bergner@hzdr.de [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328 Dresden (Germany); Gillemot, F. [Centre for Energy Research of the Hungarian Academy of Sciences, 29-33 Konkoly-Thege street, 1121 Budapest XII (Hungary); Hernández-Mayoral, M.; Serrano, M. [Division of Materials, CIEMAT, Avenida Complutense 22, 28040 Madrid (Spain); Török, G. [Wigner Research Center for Physics of the Hungarian Academy of Sciences, 29-33 Konkoly-Thege street, 1121 Budapest XII (Hungary); Ulbricht, A.; Altstadt, E. [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328 Dresden (Germany)

    2015-06-15

    Highlights: • TEM and SANS were applied to estimate mean size and number density of loops, nanovoids and Cu-rich clusters. • A three-feature dispersed-barrier hardening model was applied to estimate the yield stress increase. • The values and errors of the dimensionless obstacle strength were estimated in a consistent way. • Nanovoids are stronger obstacles for dislocation glide than dislocation loops, loops are stronger than Cu-rich clusters. • For reactor-relevant conditions, Cu-rich clusters contribute most to hardening due to their high number density. - Abstract: Dislocation loops, nanovoids and Cu-rich clusters (CRPs) are known to represent obstacles for dislocation glide in neutron-irradiated reactor pressure vessel (RPV) steels, but a consistent experimental determination of the respective obstacle strengths is still missing. A set of Cu-bearing low-Ni RPV steels and model alloys was characterized by means of SANS and TEM in order to specify mean size and number density of loops, nanovoids and CRPs. The obstacle strengths of these families were estimated by solving an over-determined set of linear equations. We have found that nanovoids are stronger than loops and loops are stronger than CRPs. Nevertheless, CRPs contribute most to irradiation hardening because of their high number density. Nanovoids were only observed for neutron fluences beyond typical end-of-life conditions of RPVs. The estimates of the obstacle strength are critically compared with reported literature data.

  7. Work hardening and mechanical equation of state in some metals in monotonic loading

    International Nuclear Information System (INIS)

    Wire, G.L.; Ellis, F.V.; Li, C.Y.

    The work hardening coefficients of Type 316 stainless steel, niobium, and 1100 aluminum alloy are measured in tensile tests. It is demonstrated experimentally that in the measured stress, plastic strain rate, and temperature range the work hardening coefficient depends only on stress and plastic strain rate. The significance of the experimental results is discussed in terms of the concept of the mechanical equation of state for plastic deformation. 13 figures

  8. Strain-hardening in nano-structured single phase steels: mechanisms and control.

    Science.gov (United States)

    Bouaziz, O; Barbier, D

    2012-11-01

    The detrimental effect of grain size refinement on the strain hardening is highlighted in single phase steels. A physical based approach for understanding the underlying mechanisms is presented. In order to overcome this limitation a promising metallurgical route exploiting the thermal stability of mechanically induced twins in austenitic steels has been successfully applied to a stainless grade confirming the opportunity to get nano-structured alloys exhibiting high yield stress with high strain-hardening.

  9. Hardening of alloys in glow discharge with the use of pulsed electric current

    International Nuclear Information System (INIS)

    Shipko, M.N.; Pomel'nikova, A.S.; Solunin, A.M.; Solunin, M.A.

    2002-01-01

    The effect of ex/ternal pulsed electric field on the thickness of a hardened surface layer of a Nd-Fe-B system alloy during chemical heat treatment in a glow discharge is studied. The relationship is established between the hardened layer thickness and the frequency of external electric field which is verified by derived equations for the relation between electron energy and pulsed electric field frequency [ru

  10. Experimental drying shrinkage of hardened cement pastes as a function of relative humidity

    DEFF Research Database (Denmark)

    Hansen, Kurt Kielsgaard; Baroghel, V.B.

    1996-01-01

    The results of an experimental study concerning drying shrinkage measured as a function of relative humidity on thin specimens of mature hardened cement pastes are presented. The results obtained at two laboratories are compared.......The results of an experimental study concerning drying shrinkage measured as a function of relative humidity on thin specimens of mature hardened cement pastes are presented. The results obtained at two laboratories are compared....

  11. Demonstration of finite element simulations in MOOSE using crystallographic models of irradiation hardening and plastic deformation

    Energy Technology Data Exchange (ETDEWEB)

    Patra, Anirban [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wen, Wei [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Martinez Saez, Enrique [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tome, Carlos [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-31

    This report describes the implementation of a crystal plasticity framework (VPSC) for irradiation hardening and plastic deformation in the finite element code, MOOSE. Constitutive models for irradiation hardening and the crystal plasticity framework are described in a previous report [1]. Here we describe these models briefly and then describe an algorithm for interfacing VPSC with finite elements. Example applications of tensile deformation of a dog bone specimen and a 3D pre-irradiated bar specimen performed using MOOSE are demonstrated.

  12. A Review of NASA's Radiation-Hardened Electronics for Space Environments Project

    Science.gov (United States)

    Keys, Andrew S.; Adams, James H.; Patrick, Marshall C.; Johnson, Michael A.; Cressler, John D.

    2008-01-01

    NASA's Radiation Hardened Electronics for Space Exploration (RHESE) project develops the advanced technologies required to produce radiation hardened electronics, processors, and devices in support of the requirements of NASA's Constellation program. Over the past year, multiple advancements have been made within each of the RHESE technology development tasks that will facilitate the success of the Constellation program elements. This paper provides a brief review of these advancements, discusses their application to Constellation projects, and addresses the plans for the coming year.

  13. Principles and techniques of radiation hardening. Volume 3. Electromagnetic pulse (EMP) and system generated EMP

    International Nuclear Information System (INIS)

    Rudie, N.J.

    1976-01-01

    The three-volume book is intended to serve as a review of the effects of thermonuclear explosion induced radiation (x-rays, gamma rays, and beta particles) and the resulting electromagnetic pulse (EMP). Volume 3 deals with the following topics: selected fundamentals of electromagnetic theory; EMP induced currents on antennas and cables; the EMP response of electronics; EMP hardening; EMP testing; injection currents; internal electromagnetic pulse (IEMP); replacement currents; and system generated electromagnetic pulse (SGEMP) hardening

  14. Experimental and Numerical Investigation of Kinematic Hardening Behavior in Sheet Metals

    International Nuclear Information System (INIS)

    Cheng, Hang Shawn; Lee, Wonoh; Cao Jian; Seniw, Mark; Wang Huiping; Chung, Kwansoo

    2007-01-01

    Characterization of material hardening behavior has been investigated by many researchers in the past decades. Experimental investigation of thin sheet metals under cyclic loading has become a challenging issue. A new test fixture has been developed to use with a regular tensile-compression machine (for example, MTS machine). Experimental results of tension-compression tests are presented followed by a review of existing testing methods. Numerical modeling of the tested data is presented using a new kinematic hardening model

  15. Effect of ferrite-martensite interface morphology on bake hardening response of DP590 steel

    International Nuclear Information System (INIS)

    Chakraborty, Arnab; Adhikary, Manashi; Venugopalan, T.; Singh, Virender; Nanda, Tarun; Kumar, B. Ravi

    2016-01-01

    The effect of martensite spatial distribution and its interface morphology on the bake hardening characteristics of a dual phase steel was investigated. In one case, typical industrial continuous annealing line parameters were employed to anneal a 67% cold rolled steel to obtain a dual phase microstructure. In the other case, a modified annealing process with changed initial heating rates and peak annealing temperature was employed. The processed specimens were further tensile pre-strained within 1–5% strain range followed by a bake hardening treatment at 170 °C for 20 min. It was observed that industrial continuous annealing line processed specimen showed a peak of about 70 MPa in bake-hardening index at 2% pre-strain level. At higher pre-strain values a gradual drop in bake-hardening index was observed. On the contrary, modified annealing process showed near uniform bake-hardening response at all pre-strain levels and a decrease could be noted only above 4% pre-strain. The evolving microstructure at each stage of annealing process and after bake-hardening treatment was studied using field emission scanning electron microscope. The microstructure analysis distinctly revealed differences in martensite spatial distribution and interface morphologies between each annealing processes employed. The modified process showed predominant formation of martensite within the ferrite grains with serrated lath martensite interfaces. This nature of the martensite was considered responsible for the observed improvement in the bake-hardening response. Furthermore, along with improved bake-hardening response negligible loss in tensile ductility was also noted. This behaviour was correlated with delayed micro-crack initiation at martensite interface due to serrated nature.

  16. An Evaluation of the Corrosion and Mechanical Performance of Interstitially Surface Hardened Stainless Steel

    Science.gov (United States)

    2013-05-10

    pitting corrosion and is present in stainless steels due to the chromium concentration in the microstructure . As the potential increases, the...carbon and nitrogen as the interstitial atom. The hardness and thickness of the surface hardened layer is characterized and compared using...hardened using available commercial techniques, using both carbon and nitrogen as the interstitial atom. The hardness and thickness of the surface

  17. Prediction and Optimization of Phase Transformation Region After Spot Continual Induction Hardening Process Using Response Surface Method

    Science.gov (United States)

    Qin, Xunpeng; Gao, Kai; Zhu, Zhenhua; Chen, Xuliang; Wang, Zhou

    2017-09-01

    The spot continual induction hardening (SCIH) process, which is a modified induction hardening, can be assembled to a five-axis cooperating computer numerical control machine tool to strengthen more than one small area or relatively large area on complicated component surface. In this study, a response surface method was presented to optimize phase transformation region after the SCIH process. The effects of five process parameters including feed velocity, input power, gap, curvature and flow rate on temperature, microstructure, microhardness and phase transformation geometry were investigated. Central composition design, a second-order response surface design, was employed to systematically estimate the empirical models of temperature and phase transformation geometry. The analysis results indicated that feed velocity has a dominant effect on the uniformity of microstructure and microhardness, domain size, oxidized track width, phase transformation width and height in the SCIH process while curvature has the largest effect on center temperature in the design space. The optimum operating conditions with 0.817, 0.845 and 0.773 of desirability values are expected to be able to minimize ratio (tempering region) and maximize phase transformation width for concave, flat and convex surface workpieces, respectively. The verification result indicated that the process parameters obtained by the model were reliable.

  18. Water deficit during pit hardening enhances phytoprostanes content, a plant biomarker of oxidative stress, in extra virgin olive oil.

    Science.gov (United States)

    Collado-González, Jacinta; Pérez-López, David; Memmi, Houssem; Gijón, M Carmen; Medina, Sonia; Durand, Thierry; Guy, Alexandre; Galano, Jean-Marie; Ferreres, Federico; Torrecillas, Arturo; Gil-Izquierdo, Angel

    2015-04-15

    No previous information exists on the effects of water deficit on the phytoprostanes (PhytoPs) content in extra virgin olive oil from fruits of mature olive (Olea europaea L. cv. Cornicabra) trees during pit hardening. PhytoPs profile in extra virgin olive oil was characterized by the presence of 9-F1t-PhytoP, 9-epi-9-F1t-PhytoP, 9-epi-9-D1t-PhytoP, 9-D1t-PhytoP, 16-B1-PhytoP + ent-16-B1-PhytoP, and 9-L1-PhytoP + ent-9-L1-PhytoP. The qualitative and quantitative differences in PhytoPs content with respect to those reported by other authors indicate a decisive effect of cultivar, oil extraction technology, and/or storage conditions prone to autoxidation. The pit hardening period was critical for extra virgin olive oil composition because water deficit enhanced the PhytoPs content, with the concomitant potential beneficial aspects on human health. From a physiological and agronomical point of view, 9-F1t-PhytoP, 9-epi-9-F1t-PhytoP, and 16-B1-PhytoP + ent-16-B1-PhytoP could be considered as early candidate biomarkers of water stress in olive tree.

  19. Microstructural Evolution of the 55 Wt Pct Al-Zn Coating During Press Hardening

    Science.gov (United States)

    Lee, Chang Wook; De Cooman, Bruno Charles

    2014-09-01

    Press hardening is increasingly being used to produce ultra-high strength steel parts for passenger cars. Al-Si, Zn, and Zn-alloy coatings have been used to provide corrosion protection to press hardening steel grades. The use of coatings has drawbacks such as coating delamination or liquid metal-induced embrittlement. In the present work, the microstructural evolution of Al-Zn coating during press hardening was studied. The 55 wt pct Al-Zn coating can in principle provide both Al barrier protection and Zn cathodic protection to press hardened steel. During the heat treatment associated with the press hardening, the 55 wt pct Al-Zn alloy coating is converted to an intermetallic surface layer of Fe2Al5 and a FeAl intermetallic diffusion layer. The Zn is separated from both intermetallic compounds and accumulates at grain boundaries and at the surface. This Zn separation process is beneficial in terms of providing cathodic protection to Al-Zn coated press hardening steel.

  20. A study on residual stresses in laser surface hardening of a medium carbon steel

    International Nuclear Information System (INIS)

    Yang, Y.S.; Na, S.J.

    1989-01-01

    The transient thermal stress and the residual stress in laser surface-hardening treatment of a medium carbon steel were analysed by employing a new two-dimensional finite element model. In this formulation, a sliced solution domain, having one element in the hardening direction, was introduced to satisfy the self-equilibrium of the resultant force in the hardening direction. By using the proposed model, the thermal and residual stresses in the laser surface heat treatment were successively calculated. The thermal stress was induced mainly by the temperature gradient and the martensitic phase transformation; the phase transformation was found to have a greater influence on the residual stress than the temperature gradient. The simulation results revealed that a compressive residual stress region occurs near the hardened surface of the workpiece and a tensile residual stress region occurs in the interior of the workpiece, whereas the maximum tensile residual stress occurs along the centre of the laser scanning path in the interior region (y=0). In comparison with the gaussian distribution of the beam power, the square beam mode results in a wider, but shallower, hardened zone. The calculation results also showed that the high-power beam with the high scanning speed is more suitable for laser surface hardening than the low-power beam with the low scanning speed if the heat input per unit length of the workpiece is maintained constant. (orig.)

  1. Study of a design criterion for 316L irradiated represented by a strain hardened material

    International Nuclear Information System (INIS)

    Gouin, H.

    1999-01-01

    The aim of this study is to analyse the consequence of radiation on different structure submitted to imposed displacement loading and for damages due to plastic instability or rupture. The main consequence of radiation is a material hardening with a ductility decrease. This effect is similar to initial mechanical hardening: the mechanical properties (determined on smooth tensile specimen) evolve in the same way while irradiation or mechanical hardening increase. So in this study, radiation hardening is simulated by mechanical hardening (swaging). Tests were carried out for which two damages were considered: plastic instability and rupture. These two damages were studied with initial mechanical hardening (5 tested hammering rate 0, 15, 25, 35 and 45% on 316L stainless steel). Likewise two types of loading were studied: tensile or bending loading on specimens with or without geometrical singularities (notches). From tensile tests, two deformation criteria are proposed for prevention against the two quoted damages. Numerical study is carried out allowing to confirm hypothesis made at the time of the tensile test result interpretation and to validate the rupture criterion by applying on bending test. (author)

  2. Process simulation and experimental validation of Hot Metal Gas Forming with new press hardening steels

    Science.gov (United States)

    Paul, A.; Reuther, F.; Neumann, S.; Albert, A.; Landgrebe, D.

    2017-09-01

    One field in the work of the Fraunhofer Institute for Machine Tools and Forming Technology IWU in Chemnitz is industry applied research in Hot Metal Gas Forming, combined with press hardening in one process step. In this paper the results of investigations on new press hardening steels from SSAB AB (Docol®1800 Bor and Docol®2000 Bor) are presented. Hot tensile tests recorded by the project partner (University of West Bohemia, Faculty of Mechanical Engineering) were used to create a material model for thermo-mechanical forming simulations. For this purpose the provided raw data were converted into flow curve approximations of the real stress-real strain-curves for both materials and afterwards integrated in a LS-DYNA simulation model of Hot Metal Gas Forming with all relevant boundary conditions and sub-stages. Preliminary experimental tests were carried out using a tool at room temperature to permit evaluation of the forming behaviour of Docol 1800 Bor and Docol 2000 Bor tubes as well as validation of the simulation model. Using this demonstrator geometry (outer diameter 57 mm, tube length 300 mm, wall thickness 1.5 mm), the intention was to perform a series of tests with different furnace temperatures (from 870 °C to 1035 °C), maximum internal pressures (up to 67 MPa) and pressure build-up rates (up to 40 MPa/s) to evaluate the formability of Docol 1800 Bor and Docol 2000 Bor. Selected demonstrator parts produced in that way were subsequently analysed by wall thickness and hardness measurements. The tests were carried out using the completely modernized Dunkes/AP&T HS3-1500 hydroforming press at the Fraunhofer IWU. In summary, creating a consistent simulation model with all relevant sub-stages was successfully established in LS-DYNA. The computation results show a high correlation with the experimental data regarding the thinning behaviour. The Hot Metal Gas Forming of the demonstrator geometry was successfully established as well. Different hardness values

  3. Hardening transition in a one-dimensional model for ferrogels.

    Science.gov (United States)

    Annunziata, Mario Alberto; Menzel, Andreas M; Löwen, Hartmut

    2013-05-28

    We introduce and investigate a coarse-grained model for quasi one-dimensional ferrogels. In our description the magnetic particles are represented by hard spheres with a magnetic dipole moment in their centers. Harmonic springs connecting these spheres mimic the presence of a cross-linked polymer matrix. A special emphasis is put on the coupling of the dipolar orientations to the elastic deformations of the matrix, where a memory effect of the orientations is included. Although the particles are displaced along one spatial direction only, the system already shows rich behavior: as a function of the magnetic dipole moment, we find a phase transition between "soft-elastic" states with finite interparticle separation and finite compressive elastic modulus on the one hand, and "hardened" states with touching particles and therefore diverging compressive elastic modulus on the other hand. Corresponding phase diagrams are derived neglecting thermal fluctuations of the magnetic particles. In addition, we consider a situation in which a spatially homogeneous magnetization is initially imprinted into the material. Depending on the strength of the magneto-mechanical coupling between the dipole orientations and the elastic deformations, the system then relaxes to a uniaxially ferromagnetic, an antiferromagnetic, or a spiral state of magnetization to minimize its energy. One purpose of our work is to provide a largely analytically solvable approach that can provide a benchmark to test future descriptions of higher complexity. From an applied point of view, our results could be exploited, for example, for the construction of novel damping devices of tunable shock absorbance.

  4. DISTRIBUTED EXTERNAL SURFACE HARDENING OF CAR DESIGN BY WINDING

    Directory of Open Access Journals (Sweden)

    O. V. Fomin

    2017-04-01

    Full Text Available Purpose. The paper involves coverage of features and results of the research conducted by the authors to determine the feasibility and establishment of pre-stressed-strained state of freight cars by winding in order to improve their strength characteristics. It is also necessary to present the theoretical justification for the effectiveness of the application of this method for car designs and an appropriate example for the tank-car. Methodology. The conducted study is based on an analysis of known works on the subject, mathematical justification and computer modeling. At the calculations of rolling stock components contemporary conventional techniques were used. Findings. Authors found that the winding method for pre-stressed-strained state is effective and appropriate for use in the construction of railway rolling stock and, in particular freight cars. Freight car designs with the pre-stressed-strained state are characterized by a number of strength advantages, among which there is an improvement of the work on the perception of operational loads and resource conservation. Originality. For the first time it is proposed the improvement of bearing capacity of freight car constructions through the creation of its component in the directed stress-strained state. It is also for the first time proposed the use of distributed external surface hardening by the method of winding to create a pre-stress-strained state of structural components of freight cars. The methods for winding designs of freight cars and their implementation were considered. Practical value. The studies developed a number of technical solutions for improving the design of freight cars and tank-container, which has been patented. Corresponding solutions for the tank-car are partially presented. Practical implementation of such solutions will significantly improve the technical, economic and operational performances of car designs.

  5. Calibration free beam hardening correction for cardiac CT perfusion imaging

    Science.gov (United States)

    Levi, Jacob; Fahmi, Rachid; Eck, Brendan L.; Fares, Anas; Wu, Hao; Vembar, Mani; Dhanantwari, Amar; Bezerra, Hiram G.; Wilson, David L.

    2016-03-01

    Myocardial perfusion imaging using CT (MPI-CT) and coronary CTA have the potential to make CT an ideal noninvasive gate-keeper for invasive coronary angiography. However, beam hardening artifacts (BHA) prevent accurate blood flow calculation in MPI-CT. BH Correction (BHC) methods require either energy-sensitive CT, not widely available, or typically a calibration-based method. We developed a calibration-free, automatic BHC (ABHC) method suitable for MPI-CT. The algorithm works with any BHC method and iteratively determines model parameters using proposed BHA-specific cost function. In this work, we use the polynomial BHC extended to three materials. The image is segmented into soft tissue, bone, and iodine images, based on mean HU and temporal enhancement. Forward projections of bone and iodine images are obtained, and in each iteration polynomial correction is applied. Corrections are then back projected and combined to obtain the current iteration's BHC image. This process is iterated until cost is minimized. We evaluate the algorithm on simulated and physical phantom images and on preclinical MPI-CT data. The scans were obtained on a prototype spectral detector CT (SDCT) scanner (Philips Healthcare). Mono-energetic reconstructed images were used as the reference. In the simulated phantom, BH streak artifacts were reduced from 12+/-2HU to 1+/-1HU and cupping was reduced by 81%. Similarly, in physical phantom, BH streak artifacts were reduced from 48+/-6HU to 1+/-5HU and cupping was reduced by 86%. In preclinical MPI-CT images, BHA was reduced from 28+/-6 HU to less than 4+/-4HU at peak enhancement. Results suggest that the algorithm can be used to reduce BHA in conventional CT and improve MPI-CT accuracy.

  6. Studies of the mechanisms involved in the laser surface hardening process of aluminum base alloys

    International Nuclear Information System (INIS)

    Silva, Luciana Ventavele da

    2011-01-01

    The Al-Si alloys are widely used in industry to replace the steel and gray cast iron in high-tech sectors. The commercial importance of these alloys is mainly due to its low weight, excellent wear (abrasion) and corrosion resistance, high resistance at elevated temperatures, low coefficient of thermal expansion and lesser fuel consumption that provide considerable reduction of emission of pollutants. In this work, Al-Si alloy used in the automotive industry to manufacture pistons of internal combustion engines, was undergone to surface treatments using LASER remelting (Nd:YAG, λ = 1.06 μm, pulsed mode). The LASER enables various energy concentrations with accurate transfer to the material without physical contact. The intense energy transfer causes the occurrence of structural changes in the superficial layer of the material. Experiments with single pulses and trails were conducted under various conditions of LASER processing in order to analyze microstructural changes resulting from treatments and their effects on the hardness. For the characterization of hardened layer was utilized the following techniques: optical microscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), x-ray mapping, Vickers microhardness and maximum roughness tests. The high cooling rate caused a change in the alloy structure due to the refinement of the primary eutectic silicon particles, resulting in increase of the mechanical properties (hardness) of the Al-Si alloy. (author)

  7. Carbonation around near aggregate regions of old hardened concrete cement paste

    International Nuclear Information System (INIS)

    Tam, Vivian W.Y.; Gao, X.F.; Tam, C.M.

    2005-01-01

    Analogous with most modern cities, waste disposal is a pressing issue due to limited landfill and public filling (land reclamation) areas in Hong Kong in which construction and demolition (C and D) waste forms the major source. Concrete, apportioning the largest portion of C and D waste, has the greatest potential for recycling. However, the knowledge on micro-structural behavior of concrete waste is immature to give adequate details on the macro-behavior of concrete waste. This paper attempts to examine the problems of recycling old concrete by investigating the microstructure and phase transformation of the concrete samples collected from buildings with 46 and 37 years of services. From the results of Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) examination, it is found that there are a lot of pores at the near layers of aggregate where carbonation of the hardened cement paste (HCP) is high. The pores may be generated as a result of poor workmanship such as insufficient concrete mixing time, trapping of air voids beneath coarse aggregate, inappropriate water to cement ratio, and the microclimate conditions such as humidity that affects the demand on water from the aggregate during mixing

  8. Microstructure, magnetic properties and magnetic hardening in 2:17 Sm-Co magnets

    International Nuclear Information System (INIS)

    Tang, W.; Zhang, Y.; Hadjipanayis, G.C.

    2002-01-01

    A comprehensive and systematic study has been made on Sm(Co,Fe,M,L) z magnets (M=Cu or Ni, and L=Zr or Ti) to completely understand the effects of composition and processing on the microstructure and magnetic properties of magnets. Ti-containing magnets do not have a lamellar phase but exhibit only a cellular microstructure, resulting in a much lower coercivity (below 10 kOe). Ni-containing magnets exhibit a perfect cellular/lamellar microstructure, but without a large domain wall energy gradient at the interface of the 2:17 and 1:5 phases, leading to a low coercivity. Only in the magnets containing both Cu and Zr, a uniform and stable cellular/lamellar microstructure with a high domain wall energy gradient across the 1:5 phase is formed, resulting in high coercivity. These results indicate that the conditions for effective magnetic hardening are: (1) Formation of a cellular/lamellar microstructure, and (2) establishment of a domain wall energy gradient at the cell boundaries. Based on all of these experimental results, the magnetization reversal mechanism of 2:17 Sm-Co magnets can be explained by both the domain wall pinning and nucleation models. The nucleation mechanism holds at any temperature in the Cu-rich magnets, and only above the Curie temperature of the 1:5 phase in the alloys with the lower Cu content. In these cases, the 2:17 cells become magnetically decoupled. (orig.)

  9. Investigations on Surface Milling of Hardened AISI 4140 Steel with Pulse Jet MQL Applicator

    Science.gov (United States)

    Bashir, Mahmood Al; Mia, Mozammel; Dhar, Nikhil Ranjan

    2016-06-01

    In this article, an experimental investigation was performed in milling hardened AISI 4140 steel of hardness 40 HRC. The machining was performed in both dry and minimal quantity lubricant (MQL) conditions, as part of neat machining, to make a strong comparison of the undertaken machining environments. The MQL was impinged int the form of pulse jet, by using the specially developed pulse-jet-attachment, to ensure that the cutting fluid can be applied in different timed pulses and quantities at critical zones. The tool wear, cutting force and surface roughness were taken as the quality responses while cutting speed, table feed rate and flow rate of the pulse were considered as influential factors. The depth of cut was kept constant at 1.50 mm because of its less significant effects and the straight oil was adopted as cutting fluid in pulse-jet-MQL. The effects of different factors, on the quality responses, are analyzed using ANOVA. It is observed that MQL applicator system exhibits overall better performance when compared to dry milling by reducing surface roughness, cutting force and prolonging tool life but a flow rate of 150 ml/h has tremendous effects on the responses. This investigation and afterward results are expected to aid the industrial practitioner and researcher to adopt the pulse-MQL in high speed milling to prolong tool life, reduce tool wear, diminish cutting force generation and promote better surface finish.

  10. Comparative Studies on the Wear of ADI Alloy Cast Irons as Well as Selected Steels and Surface-Hardened Alloy Cast Steels in the Presence of Abrasive

    Directory of Open Access Journals (Sweden)

    Wieczorek A. N.

    2017-03-01

    Full Text Available The paper presents the results of wear tests obtained for 4 groups of materials: surface-hardened alloy steels and alloy cast steels for structural applications, hard-wearing surface-hardened alloy cast steels, and austempered alloy cast irons. The wear tests have been performed on a specially designed test rig that allows reproducing the real operating conditions of chain wheels, including the rolling and sliding form of contact between elements. The chain wheels subjected to tests were operated with the use of loose quartz abrasive. This study presents results of measurements of material parameters, micro-structure of a surface subject to wear, as well as the linear wear determined for the materials considered. Based on the results, the following was found: the best wear properties were obtained for surface-hardened alloy steels and wear surface; strengthening of the ADI surface took place - most probably as a result of transformation of austenite into martensite; the uniformity of the structure of the materials affects the surface wear process. The study also indicated a significant degree of graphite deformation in ADI characterized by the upper ausferritic structure and its oblique orientation in relation to the surface, which resulted in a facilitated degradation of the surface caused by the quartz abrasive.

  11. Effect of high-manganese cast steel strain hardening on the abrasion wear resistance in a mixture of SiC and water

    Directory of Open Access Journals (Sweden)

    Kalandyk B.

    2013-12-01

    Full Text Available The study attempts to determine the impact of the high-manganese cast steel strain hardening on its abrasion wear resistance in a mixture of SiC and water prepared in accordance with ASTM G75. For tests, the high-manganese cast steel containing 10.7, 17.9 and 20.02% Mn was selected. The results of microstructure examinations and abrasion wear resistance tests carried out on the material in non-hardened condition and after strain hardening with a force of 539.55kN were disclosed. Additionally, the surface of samples after a 16-hour cycle of abrasion tests was examined. Moreover, based on the obtained results, the effect of different contents of Mn in cast steel was studied, mainly in terms of its impact on the abrasion wear resistance. The results obtained on the tested materials were compared with the results obtained on the low-alloyed abrasion wear-resistant cast steel L35GSM.

  12. Investigation of modulus hardening of various co-clusters in aged Al-Cu-Mg-Ag alloy by atom probe tomography

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Song [Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha 410083 (China); School of Material Science and Engineering, Central South University, Changsha 410083 (China); Liu, Zhiyi, E-mail: liuzhiyi@csu.edu.cn [Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha 410083 (China); School of Material Science and Engineering, Central South University, Changsha 410083 (China); Ying, Puyou; Wang, Jian; Li, Junlin [Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha 410083 (China); School of Material Science and Engineering, Central South University, Changsha 410083 (China)

    2016-06-21

    The modulus hardening capability of various co-clusters in a low Cu/Mg ratio Al-Cu-Mg-Ag alloy aged at 165 °C is investigated by quantitative atom probe tomography analysis. Prolonged aging from 5 min to 2 h leads to the simultaneous increase in the critical shear stress of both Mg-Ag and Cu-Mg co-clusters. Regardless of the higher shear modulus of Cu-Mg co-clusters, calculation results show that Mg-Ag co-clusters possess a greater modulus hardening capability than Cu-Mg co-clusters, suggesting its primary contribution to the rapid hardening at the early aging stage. As aging extends from 30 min to 2 h, the increment in the critical shear stress of Mg-Ag co-clusters is lower than that of Cu-Mg co-clusters due to the precipitation of high density Ω phase. In addition, the shear modulus of Mg-Ag co-clusters is generally independent on its size at each investigated condition.

  13. Experimental investigation on flank wear and tool life, cost analysis and mathematical model in turning hardened steel using coated carbide inserts

    Directory of Open Access Journals (Sweden)

    Ashok Kumar Sahoo

    2013-10-01

    Full Text Available Turning hardened component with PCBN and ceramic inserts have been extensively used recently and replaces traditional grinding operation. The use of inexpensive multilayer coated carbide insert in hard turning is lacking and hence there is a need to investigate the potential and applicability of such tools in turning hardened steels. An attempt has been made in this paper to have a study on turning hardened AISI 4340 steel (47 ± 1 HRC using coated carbide inserts (TiN/TiCN/Al2O3/ZrCN under dry environment. The aim is to assess the tool life of inserts and evolution of flank wear with successive machining time. From experimental investigations, the gradual growth of flank wear for multilayer coated insert indicates steady machining without any premature tool failure by chipping or fracturing. Abrasion is found to be the dominant wear mechanisms in hard turning. Tool life of multilayer coated carbide inserts has been found to be 31 minute and machining cost per part is Rs.3.64 only under parametric conditions chosen i.e. v = 90 m/min, f = 0.05 mm/rev and d = 0.5 mm. The mathematical model shows high determination coefficient, R2 (99% and fits the actual data well. The predicted flank wear has been found to lie very close to the experimental value at 95% confidence level. This shows the potential and effectiveness of multilayer coated carbide insert used in hard turning applications.

  14. The role of strain hardening in the transition from dislocation-mediated to frictional deformation of marbles within the Karakoram Fault Zone, NW India

    Science.gov (United States)

    Wallis, David; Lloyd, Geoffrey E.; Hansen, Lars N.

    2018-02-01

    The onset of frictional failure and potentially seismogenic deformation in carbonate rocks undergoing exhumation within fault zones depends on hardening processes that reduce the efficiency of aseismic dislocation-mediated deformation as temperature decreases. However, few techniques are available for quantitative analysis of dislocation slip system activity and hardening in natural tectonites. Electron backscatter diffraction maps of crystal orientations offer one such approach via determination of Schmid factors, if the palaeostress conditions can be inferred and the critical resolved shear stresses of slip systems are constrained. We analyse calcite marbles deformed in simple shear within the Karakoram Fault Zone, NW India, to quantify changes in slip system activity as the rocks cooled during exhumation. Microstructural evidence demonstrates that between ∼300 °C and 200-250 °C the dominant deformation mechanisms transitioned from dislocation-mediated flow to twinning and frictional failure. However, Schmid factor analysis, considering critical resolved shear stresses for yield of undeformed single crystals, indicates that the fraction of grains with sufficient resolved shear stress for glide apparently increased with decreasing temperature. Misorientation analysis and previous experimental data indicate that strain-dependent work hardening is responsible for this apparent inconsistency and promoted the transition from dislocation-mediated flow to frictional, and potentially seismogenic, deformation.

  15. Study of the mechanisms involved in the laser superficial hardening process of metallic alloys

    International Nuclear Information System (INIS)

    Silva, Edmara Marques Rodrigues da

    2001-01-01

    The laser superficial hardening process of a ferrous alloy (gray cast iron) and of an aluminum-silicon alloy was investigated in this work. These metallic alloys are used in the automobile industry for manufacturing cylinders and pistons, respectively. By application of individual pulses and single tracks, the involved mechanisms during the processing were studied. Variables such as energy density, power density, temporal width, beam diameter on the sample surface, atmosphere of the processing region, overlapping and scanning velocity. The hardened surface was characterized by optical and scanning electronic microscopy, dispersive energy microanalysis, X-ray mapping, X-ray diffraction, and measurements of roughness and Vickers microhardness. Depending on the processing parameters, it is possible to obtain different microstructures. The affected area of gray cast iron, can be hardened by remelting or transformation hardening (total or partial) if the reached temperature is higher or not that of melting temperature. Laser treatment originated new structures such as retained austenite, martensite and, occasionally, eutectic of cellular dendritic structure. Aluminum-silicon alloy does not have phase transformation in solid state, it can be hardened only by remelting. The increase of hardness is a function of the precipitation hardening process, which makes the silicon particles smaller and more disperse in the matrix. Maximal values of microhardness (700-1000 HV) were reached with the laser treatment in gray cast iron samples. The initial microhardness is of 242 HV. For aluminum-silicon alloy, the laser remelting increases the initial microhardness of 128 HV to the range of 160-320 HV. The found results give a new perspective for using the CLA/IPEN's laser in the heat treatment area. Besides providing a higher absorptivity to the materials, compared with the CO 2 laser, and optical fiber access, the superficial hardening with Nd:YAG laser, depending on the level of

  16. Neutron energy spectrum influence on irradiation hardening and microstructural development of tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Fukuda, Makoto, E-mail: makoto.fukuda@qse.tohoku.ac.jp [Tohoku University, Sendai, 980-8579 (Japan); Kiran Kumar, N.A.P.; Koyanagi, Takaaki; Garrison, Lauren M. [Oak Ridge National Laboratory, Oak Ridge, TN, 37831 (United States); Snead, Lance L. [Massachusetts Institute of Technology, Cambridge, MA, 02139 (United States); Katoh, Yutai [Oak Ridge National Laboratory, Oak Ridge, TN, 37831 (United States); Hasegawa, Akira [Tohoku University, Sendai, 980-8579 (Japan)

    2016-10-15

    Neutron irradiation to single crystal pure tungsten was performed in the mixed spectrum High Flux Isotope Reactor (HFIR). To investigate the influences of neutron energy spectrum, the microstructure and irradiation hardening were compared with previous data obtained from the irradiation campaigns in the mixed spectrum Japan Material Testing Reactor (JMTR) and the sodium-cooled fast reactor Joyo. The irradiation temperatures were in the range of ∼90–∼800 °C and fast neutron fluences were 0.02–9.00 × 10{sup 25} n/m{sup 2} (E > 0.1 MeV). Post irradiation evaluation included Vickers hardness measurements and transmission electron microscopy. The hardness and microstructure changes exhibited a clear dependence on the neutron energy spectrum. The hardness appeared to increase with increasing thermal neutron flux when fast fluence exceeds 1 × 10{sup 25} n/m{sup 2} (E > 0.1 MeV). Irradiation induced precipitates considered to be χ- and σ-phases were observed in samples irradiated to >1 × 10{sup 25} n/m{sup 2} (E > 0.1 MeV), which were pronounced at high dose and due to the very high thermal neutron flux of HFIR. Although the irradiation hardening mainly caused by defects clusters in a low dose regime, the transmutation-induced precipitation appeared to impose additional significant hardening of the tungsten. - Highlights: • The microstructure and irradiation hardening of single crystal pure W irradiated in HFIR was investigated. • The neutron energy spectrum influence was evaluated by comparing the HFIR results with previous work in Joyo and JMTR. • In the dose range up to ∼1 dpa, the neutron energy spectrum influence of irradiation hardening was not clear. • In the dose range above 1 dpa, the neutron energy influence on irradiation hardening and microstructural development was clearly observed. • The irradiation induced precipitates caused significant irradiation hardening of pure W irradiated in HFIR.

  17. Microstructural evolution and the variation of tensile behavior after aging heat treatment of precipitation hardened martensitic steel

    International Nuclear Information System (INIS)

    Shin, Jong-Ho; Jeong, JaeSuk; Lee, Jong-Wook

    2015-01-01

    The effects of aging temperature on the microstructural evolution and the tensile behavior of precipitation hardened martensitic steel were investigated. Microscopic analysis using transmission electron microscope (TEM) was combined with the microstructural analysis using the synchrotron X-ray diffraction (XRD) to characterize the microstructural evolution with aging temperature. Peak hardness was obtained by precipitation of the Ni 3 Al ordered phase. After aging at temperature range from 420 to 590 °C, spherical Ni 3 Al precipitates and ellipsoidal M 23 C 6 carbides were observed within laths and at lath boundaries, respectively. Strain hardening behavior was analyzed with Ludwik equation. It is observed that the plastic strain regimes can be divided into two different stages by a rapid increase in strain hardening followed by a comparatively lower increase. At the first strain hardening stage, the aged specimen exhibited higher strain hardening exponent than the as-quenched specimen, and the exponent in the aged specimen was not changed considerably with increasing aging temperature. It is revealed that the strain hardening exponents at the first and the second stages were associated with the Ni 3 Al precipitates and the domain size representing the coherent scattering area, respectively. - Highlights: • All of aged specimen exhibited higher strain hardening exponent than the as-quenched specimen at the first stage. • The value of strain hardening exponent in the aged specimen was nearly constant with aging temperature. • Ni 3 Al precipitation dominantly influenced to the increase of strain hardening exponent at the first strain hardening stage. • Domain size was associated with strain hardening exponent at the second strain hardening stage

  18. Innovative Structural Materials and Sections with Strain Hardening Cementitious Composites

    Science.gov (United States)

    Dey, Vikram

    The motivation of this work is based on development of new construction products with strain hardening cementitious composites (SHCC) geared towards sustainable residential applications. The proposed research has three main objectives: automation of existing manufacturing systems for SHCC laminates; multi-level characterization of mechanical properties of fiber, matrix, interface and composites phases using servo-hydraulic and digital image correlation techniques. Structural behavior of these systems were predicted using ductility based design procedures using classical laminate theory and structural mechanics. SHCC sections are made up of thin sections of matrix with Portland cement based binder and fine aggregates impregnating continuous one-dimensional fibers in individual or bundle form or two/three dimensional woven, bonded or knitted textiles. Traditional fiber reinforced concrete (FRC) use random dispersed chopped fibers in the matrix at a low volume fractions, typically 1-2% to avoid to avoid fiber agglomeration and balling. In conventional FRC, fracture localization occurs immediately after the first crack, resulting in only minor improvement in toughness and tensile strength. However in SHCC systems, distribution of cracking throughout the specimen is facilitated by the fiber bridging mechanism. Influence of material properties of yarn, composition, geometry and weave patterns of textile in the behavior of laminated SHCC skin composites were investigated. Contribution of the cementitious matrix in the early age and long-term performance of laminated composites was studied with supplementary cementitious materials such as fly ash, silica fume, and wollastonite. A closed form model with classical laminate theory and ply discount method, coupled with a damage evolution model was utilized to simulate the non-linear tensile response of these composite materials. A constitutive material model developed earlier in the group was utilized to characterize and

  19. A method for hardening or curing adhesives for flocking thermally sensitive substrata by means of an electron-beam

    International Nuclear Information System (INIS)

    Nablo, S.V.; Fussa, A.D.

    1975-01-01

    The invention relates to a method for hardening or curing adhesives for flocking thermally sensitive substrata by means of an electron-beam. That method consists in accurately adjusting the parameters of irradiation by an electron-beam and the beam velocity so as to obtain, a very rapid hardening of adhesives used for fixing flocking materials, or the like, to thermally sensitive substrate. That can be applied to hardening or curing adhesives for flocking thermally-sensitive substrata which normally restrict the hardening rate [fr

  20. Evaluating system reliability and targeted hardening strategies of power distribution systems subjected to hurricanes

    International Nuclear Information System (INIS)

    Salman, Abdullahi M.; Li, Yue; Stewart, Mark G.

    2015-01-01

    Over the years, power distribution systems have been vulnerable to extensive damage from hurricanes which can cause power outage resulting in millions of dollars of economic losses and restoration costs. Most of the outage is as a result of failure of distribution support structures. Over the years, various methods of strengthening distribution systems have been proposed and studied. Some of these methods, such as undergrounding of the system, have been shown to be unjustified from an economic point of view. A potential cost-effective strategy is targeted hardening of the system. This, however, requires a method of determining critical parts of a system that when strengthened, will have greater impact on reliability. This paper presents a framework for studying the effectiveness of targeted hardening strategies on power distribution systems subjected to hurricanes. The framework includes a methodology for evaluating system reliability that relates failure of poles and power delivery, determination of critical parts of a system, hurricane hazard analysis, and consideration of decay of distribution poles. The framework also incorporates cost analysis that considers economic losses due to power outage. A notional power distribution system is used to demonstrate the framework by evaluating and comparing the effectiveness of three hardening measures. - Highlight: • Risk assessment of power distribution systems subjected to hurricanes is carried out. • Framework for studying effectiveness of targeted hardening strategies is presented. • A system reliability method is proposed. • Targeted hardening is cost effective for existing systems. • Economic losses due to power outage should be considered for cost analysis.

  1. Effect of pre-hardening on the lifetime of type 304L austenitic stainless steels

    International Nuclear Information System (INIS)

    Kpodekon, C.

    2010-01-01

    This study deals with the effect of the loading history on the cyclic behavior and the fatigue life of two kinds (THYSSEN and CLI) of 304L stainless steel at room temperature. The experiments have been performed using two specimens' categories. The first one (virgin) has been submitted to only classical fatigue tests while in the second category, prior to the fatigue test, the specimen is subjected to a pre-hardening process under either monotonic or cyclic strain control. Cyclic softening followed by cyclic hardening are observed for the virgin specimens while only cyclic softening is exhibited by the pre-hardened specimens. The obtained results show that fatigue life is strongly influenced by the pre-hardening: it seems beneficial under stress control but detrimental under strain control, even in the presence of a compressive mean stress. The results are discussed regarding the cyclic evolution of the elastic modulus as well as the isotropic and kinematic parts of the strain hardening, and strain energy density per cycle, in different configurations: with or without prehardening,stress or strain control. (author)

  2. Investigation on the effect of chemical composition on the texture and bake hardening I F steels

    International Nuclear Information System (INIS)

    Kariman, M.; Motaghi, A.; Raygan, Sh.; Habibi Parsa, M.; Nili Ahmadabadi, M.

    2008-01-01

    Interstitial free steels have good formability and also excellent deep draw ability. These features make them one of the applicable materials in automotive industry. Chemical composition and thermomechanical treatment used to process these steels have important role in final properties of them. In this study, the effect of chemical composition on texture, anisotropic properties and bake harden ability of these steels were investigated. The results showed that contribution of vanadium as a weak carbonitride former element with titanium as strong carbonitride former could change the texture of steels. Replacing titanium with vanadium caused harmful effect on mechanical properties. In this research deep drawing properties of five steels were compared based on I {111} / I{001} and I {111} / I{110} parameters. The results of bake harden ability test showed that there were critical limits for vanadium volume fractions above which bake harden properties was improved. It was shown that the bake harden properties of Nb-steels were better than that of Ti-steels. This was due to the better solution of Nb(C,N) compared to Ti(C,N). Addition of vanadium to Ti-steels may improve bake harden properties of I F steels

  3. Effect of Annealing on Microstructures and Hardening of Helium-Hydrogen-Implanted Sequentially Vanadium Alloys

    Science.gov (United States)

    Jiang, Shaoning; Wang, Zhiming

    2018-03-01

    The effect of post-irradiation annealing on the microstructures and mechanical properties of V-4Cr-4Ti alloys was studied. Helium-hydrogen-irradiated sequentially V-4Cr-4Ti alloys at room temperature (RT) were undergone post-irradiation annealing at 450 °C over periods of up to 30 h. These samples were carried out by high-resolution transmission electron microscopy (HRTEM) observation and nanoindentation test. With the holding time, large amounts of point defects produced during irradiation at RT accumulated into large dislocation loops and then dislocation nets which promoted the irradiation hardening. Meanwhile, bubbles appeared. As annealing time extended, these bubbles grew up and merged, and finally broke up. In the process, the size of bubbles increased and the number density decreased. Microstructural changes due to post-irradiation annealing corresponded to the change of hardening. Dislocations and bubbles are co-contributed to irradiation hardening. With the holding time up to 30 h, the recovery of hardening is not obvious. The phenomenon was discussed by dispersed barrier hardening model and Friedel-Kroupa-Hirsch relationship.

  4. Superimposed behaviour of g(m) under ABA-induced stomata closing and low CO2

    Czech Academy of Sciences Publication Activity Database

    Tazoe, Y.; Šantrůček, Jiří

    2015-01-01

    Roč. 38, č. 3 (2015), s. 385-387 ISSN 0140-7791 R&D Projects: GA ČR(CZ) GAP501/12/1261 Institutional support: RVO:60077344 Keywords : Mesophyll conductance * Carbon-isotope discrimination * Photosnthesis * Plants Subject RIV: CE - Biochemistry Impact factor: 6.169, year: 2015

  5. A Comprehensive Proteomic Survey of ABA-Induced Protein Phosphorylation in Rice (Oryza sativa L.).

    Science.gov (United States)

    Qiu, Jiehua; Hou, Yuxuan; Wang, Yifeng; Li, Zhiyong; Zhao, Juan; Tong, Xiaohong; Lin, Haiyan; Wei, Xiangjin; Ao, Hejun; Zhang, Jian

    2017-01-03

    abscisic acid (ABA) is a key phytohormone regulating plant development and stress response. The signal transduction of ABA largely relies on protein phosphorylation. However; little is known about the phosphorylation events occurring during ABA signaling in rice thus far. By employing a label-free; MS (Mass Spectrometry)-based phosphoproteomic approach; we identified 2271 phosphosites of young rice seedlings and their intensity dynamics in response to ABA; during which 1060 proteins were found to be differentially phosphorylated. Western-blot analysis verified the differential phosphorylation pattern of D1, SMG1 and SAPK9 as indicated by the MS result; suggesting the high reliability of our phosphoproteomic data. The DP (differentially phosphorylated) proteins are extensively involved in ABA as well as other hormone signaling pathways. It is suggested that ABA antagonistically regulates brassinosteroid (BR) signaling via inhibiting BR receptor activity. The result of this study not only expanded our knowledge of rice phosphoproteome, but also shed more light on the pattern of protein phosphorylation in ABA signaling.

  6. A new discrete dynamic model of ABA-induced stomatal closure predicts key feedback loops.

    Directory of Open Access Journals (Sweden)

    Réka Albert

    2017-09-01

    Full Text Available Stomata, microscopic pores in leaf surfaces through which water loss and carbon dioxide uptake occur, are closed in response to drought by the phytohormone abscisic acid (ABA. This process is vital for drought tolerance and has been the topic of extensive experimental investigation in the last decades. Although a core signaling chain has been elucidated consisting of ABA binding to receptors, which alleviates negative regulation by protein phosphatases 2C (PP2Cs of the protein kinase OPEN STOMATA 1 (OST1 and ultimately results in activation of anion channels, osmotic water loss, and stomatal closure, over 70 additional components have been identified, yet their relationships with each other and the core components are poorly elucidated. We integrated and processed hundreds of disparate observations regarding ABA signal transduction responses underlying stomatal closure into a network of 84 nodes and 156 edges and, as a result, established those relationships, including identification of a 36-node, strongly connected (feedback-rich component as well as its in- and out-components. The network's domination by a feedback-rich component may reflect a general feature of rapid signaling events. We developed a discrete dynamic model of this network and elucidated the effects of ABA plus knockout or constitutive activity of 79 nodes on both the outcome of the system (closure and the status of all internal nodes. The model, with more than 1024 system states, is far from fully determined by the available data, yet model results agree with existing experiments in 82 cases and disagree in only 17 cases, a validation rate of 75%. Our results reveal nodes that could be engineered to impact stomatal closure in a controlled fashion and also provide over 140 novel predictions for which experimental data are currently lacking. Noting the paucity of wet-bench data regarding combinatorial effects of ABA and internal node activation, we experimentally confirmed several predictions of the model with regard to reactive oxygen species, cytosolic Ca2+ (Ca2+c, and heterotrimeric G-protein signaling. We analyzed dynamics-determining positive and negative feedback loops, thereby elucidating the attractor (dynamic behavior repertoire of the system and the groups of nodes that determine each attractor. Based on this analysis, we predict the likely presence of a previously unrecognized feedback mechanism dependent on Ca2+c. This mechanism would provide model agreement with 10 additional experimental observations, for a validation rate of 85%. Our research underscores the importance of feedback regulation in generating robust and adaptable biological responses. The high validation rate of our model illustrates the advantages of discrete dynamic modeling for complex, nonlinear systems common in biology.

  7. Rapid magnetic hardening by rapid thermal annealing in NdFeB-based nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Chu, K.-T.; Jin, Z Q; Chakka, Vamsi M; Liu, J P [Department of Physics, University of Texas at Arlington, Arlington, TX 76019 (United States)

    2005-11-21

    A systematic study of heat treatments and magnetic hardening of NdFeB-based melt-spun nanocomposite ribbons have been carried out. Comparison was made between samples treated by rapid thermal annealing and by conventional furnace annealing. Heating rates up to 200 K s{sup -1} were adopted in the rapid thermal processing. It was observed that magnetic hardening can be realized in an annealing time as short as 1 s. Coercivity of 10.2 kOe in the nanocomposites has been obtained by rapid thermal annealing for 1 s, and prolonged annealing did not give any increase in coercivity. Detailed results on the effects of annealing time, temperature and heating rate have been obtained. The dependence of magnetic properties on the annealing parameters has been investigated. Structural characterization revealed that there is a close correlation between magnetic hardening and nanostructured morphology. The coercivity mechanism was also studied by analysing the magnetization minor loops.

  8. Formation and evolution of the hardening precipitates in a Mg-Y-Nd alloy

    Energy Technology Data Exchange (ETDEWEB)

    Barucca, G. [Dipartimento di Fisica e Ingegneria dei Materiali e del Territorio, Universita Politecnica delle Marche, Via Brecce Bianche, I-60131 Ancona (Italy); Ferragut, R. [Dipartimento di Fisica, LNESS and CNISM, Politecnico di Milano, Via Anzani 42, I-22100 Como (Italy); Fiori, F. [Dipartimento SAIFET, Sezione di Scienze Fisiche, Universita Politecnica delle Marche, Via Brecce Bianche, I-60131 Ancona (Italy); Lussana, D. [Dipartimento di Chimica IFM and NIS Centre, Universita di Torino, Via P. Giuria 9, I-10125 Torino (Italy); Mengucci, P., E-mail: p.mengucci@univpm.it [Dipartimento di Fisica e Ingegneria dei Materiali e del Territorio, Universita Politecnica delle Marche, Via Brecce Bianche, I-60131 Ancona (Italy); Moia, F. [Dipartimento di Fisica, LNESS and CNISM, Politecnico di Milano, Via Anzani 42, I-22100 Como (Italy); Riontino, G. [Dipartimento di Chimica IFM and NIS Centre, Universita di Torino, Via P. Giuria 9, I-10125 Torino (Italy)

    2011-06-15

    The formation and evolution of hardening precipitates in a Mg-Y-Nd (WE43) alloy during artificial ageing at 150 and 210 deg. C is followed by small angle X-ray scattering (SAXS) measurements, Vickers microhardness tests and transmission electron microscopy (TEM) observations. A quantitative description of the alloy studied during the early and advanced stages of the precipitation sequence is presented. In situ SAXS evolution at 210 deg. C of the size, volume fraction and number density of the subnanometer and nanometer particles that evolve in the {beta}'' phase was obtained. TEM and microhardness results indicate that the hardening mechanism is based on {beta}'' transformation of pre-precipitates and their growth at 150 deg. C, while at 210 deg. C hardening is mainly associated with {beta}'' {yields} {beta}' transformation.

  9. Deforming glassy polystyrene: Influence of pressure, thermal history, and deformation mode on yielding and hardening.

    Science.gov (United States)

    Vorselaars, Bart; Lyulin, Alexey V; Michels, M A J

    2009-02-21

    The toughness of a polymer glass is determined by the interplay of yielding, strain softening, and strain hardening. Molecular-dynamics simulations of a typical polymer glass, atactic polystyrene, under the influence of active deformation have been carried out to enlighten these processes. It is observed that the dominant interaction for the yield peak is of interchain nature and for the strain hardening of intrachain nature. A connection is made with the microscopic cage-to-cage motion. It is found that the deformation does not lead to complete erasure of the thermal history but that differences persist at large length scales. Also we find that the strain-hardening modulus increases with increasing external pressure. This new observation cannot be explained by current theories such as the one based on the entanglement picture and the inclusion of this effect will lead to an improvement in constitutive modeling.

  10. Stress corrosion cracking tests for low carbon stainless steels with work hardened layer

    International Nuclear Information System (INIS)

    Nakano, Junichi; Kikuchi, Masahiko; Tsukada, Takashi

    2005-01-01

    To avoid introduction of Cr depletion at grain boundaries by welding process, low carbon stainless steels (SSs) were used in corrosive environment as one of countermeasures for Stress Corrosion Cracking (SCC). Recently, it is reported that SCCs were introduced at portion with work hardened layer although low carbon SSs had been used at core shrouds and primary loop recirculation piping in Boiling Water Reactors. To simulate and examine the phenomenon, mechanical working, metallographic observation, hardness test and SCC tests in chloride solutions were conducted for low carbon SSs. From the results of metallographic observation and hardness test, it was confirmed that slip bands were observed around the surface and hardened layer was introduced by mechanical working. From the results of SCC tests, it was noticed that cracks which introduced from the surface, had grown into the matrix. It is thought that low carbon SSs with work hardened layer have susceptibility to SCC from the above. (author)

  11. Ferrous arrowheads and their oil quench hardening: Some early Indian evidence

    Science.gov (United States)

    Dube, R. K.

    2008-05-01

    A wide variety of ferrous arrowheads were in use in ancient India. Several typical chemical analyses of arrowheads found from archaeological excavation carried out at Kaushambi are reported in this paper. The average carbon content of these arrowheads varied from as low as 0.1 wt.% to approximately 0.9 wt.%. Literary evidence for oil quench hardening of ferrous arrowheads, as reported in famous Sanskrit epics—the Rāmāyana and the Mahābhārata—have been discussed in this paper. This type of quench hardening was intentionally adopted as it helped in preventing distortion and formation of quench cracks in arrowheads. The oil quench-hardened arrowheads were rubbed on stones to sharpen them, which also brought about tempering of martensite due to frictional heat.

  12. Neutron diffraction study on anisotropy of strain age hardening in ferritic steel

    International Nuclear Information System (INIS)

    Suzuki, Tetsuya; Yamanaka, Keisuke; Ishino, Mayuko; Shinohara, Yasuhiro; Nagai, Kensuke; Tsuru, Eiji; Xu, Pingguang

    2012-01-01

    The work-hardening characteristics of anisotropic tensile deformations and the corresponding residual strain changes of pre-strained ferritic steels without and with aging treatment were investigated by using angle dispersive neutron diffraction and electron backscatter diffraction pattern analysis. The plastic deformation along the pre-strained direction leads to evident work-hardening at the beginning stage, showing discontinuous yielding behavior. Comparably, the plastic deformation perpendicular to the pre-strained direction shows continuously yielding. The tensile and compressive residual strains were found in the and grains along the pre-strained direction, respectively. It is also found that the difference in various oriented grains after strain aging become more evident along the pre-strained direction but smaller perpendicular to the pre-strained direction, revealing a higher work hardening capability in the former case than in the latter case. (author)

  13. State of the art of durability-performance evaluation of hardened cement based on phase compositions

    International Nuclear Information System (INIS)

    Kurashige, Isao; Imoto, Harutake; Yamamoto, Takeshi; Hironaga, Michihiko

    2006-01-01

    Upgrading durability-performance evaluation technique for concrete is urgently demanded in connection to its application to radio-active waste repository which needs ultra long-term durability. Common concrete structures also require an advanced method for minimizing the life-cycle cost. The purpose of this research is to investigate current problems and future tasks on durability-performance evaluation of hardened cement from the view point of phase composition. Although the phase composition of hardened cement has not fully been reflected to durability-performance evaluation, it influences concrete durability as well as its pore structure. This report reviews state of the art of the factors affecting phase composition, analytical and experimental evaluation techniques for phase composition, and durability-performance evaluation methods of hardened cement based on phase composition. (author)

  14. Anisotropic Hardening Behaviour and Springback of Advanced High-Strength Steels

    Directory of Open Access Journals (Sweden)

    Jaebong Jung

    2017-11-01

    Full Text Available Advanced high-strength steels (AHSSs exhibit large, and sometimes anisotropic, springback recovery after forming. Accurate description of the anisotropic elasto-plastic behaviour of sheet metals is critical for predicting their anisotropic springback behaviour. For some materials, the initial anisotropy is maintained while hardening progresses. However, for other materials, anisotropy changes with hardening. In this work, to account for the evolution of anisotropy of a dual-phase steel, an elastoplastic material constitutive model is developed. In particular, the combined isotropic–kinematic hardening model was modified. Tensile loading–unloading, uniaxial and biaxial tension, and tension–compression tests were conducted along the rolling, diagonal, and transverse directions to measure the anisotropic properties, and the parameters of the proposed constitutive model were determined. For validation, the proposed model was applied to a U-bending process, and the measured springback angles were compared to the predicted ones.

  15. Effect of MWCNT reinforcement on the precipitation-hardening behavior of AA2219

    Science.gov (United States)

    Thomas, Shijo; Umasankar, V.

    2018-01-01

    Aluminum alloy matrix composites have found a predominant place in research, and their applications are explored in almost all industries. The aerospace industry has been using precipitation-hardenable alloys in structural applications. However, insufficient literature is available on the influence of multiwalled carbon nanotubes (MWCNTs) on precipitation-hardenable alloy composite materials; thus, this work was designed to elucidate the effect on MWCNT reinforcement on AA2219 with and without precipitation hardening. Reinforcement with MWCNTs has been reported to accelerate precipitation and to achieve greater hardness within a much shorter time. The addition of 0.75wt% MWCNTs resulted in maximal hardness at 90 min, which is approximately 27% of improvement over the maximum hardness achieved by the corresponding monolithic alloy after 10 h of aging. The sample reinforced with 0.75wt% MWCNTs showed an improvement of 82% in hardness by solutionizing and aging compared to that achieved by sintering.

  16. Simulation-aided investigation of beam hardening induced errors in CT dimensional metrology

    DEFF Research Database (Denmark)

    Tan, Ye; Kiekens, Kim; Welkenhuyzen, Frank

    2014-01-01

    are mutually correlated, it remains challenging to interpret measurement results and to identify the distinct error sources. Since simulations allow isolating the different affecting factors, they form a useful complement to experimental investigations. Dewulf et al (2012 CIRP Ann. Manuf. Technol. 61 495......–8) investigated the influence of beam hardening correction parameters on the diameter of a calibrated steel pin in different experimental set-ups. It was clearly shown that an inappropriate beam hardening correction can result in significant dimensional errors. This paper confirms these results using simulations...... of a pin surrounded by a stepped cylinder: a clear discontinuity in the measured diameter of the inner pin is observed where it enters the surrounding material. The results are expanded with an investigation of the beam hardening effect on the measurement results for both inner and outer diameters...

  17. Simulation-aided investigation of beam hardening induced errors in CT dimensional metrology

    DEFF Research Database (Denmark)

    Tan, Ye; Kiekens, Kim; Welkenhuyzen, Frank

    2013-01-01

    most of these factors are mutually correlated, it remains challenging to interpret measurement results and to identify the distinct error sources. Since simulations allow isolating the different affecting factors, they form a useful complement to experimental investigations. Dewulf et.al [5......] investigated the influence of beam hardening correction parameters on the diameter of a calibrated steel pin in different experimental set-ups. It was clearly shown that inappropriate beam hardening correction can result in significant dimensional errors. This paper confirms these results using simulations...... of a pin surrounded by a stepped cylinder: a clear discontinuity in the measured diameter of the inner pin is observed where it enters the surrounding material. The results are expanded with an investigation of the beam hardening effect on the measurement results for both inner and outer diameters...

  18. Age Hardening Kinetics in 7xxx Type (Al-Mg-Zn) Alloys

    Science.gov (United States)

    Vevecka-Priftaj, A.; Lamani, E.; Fjerdingen, J.; Langsrud, Y.; Gjønnes, J.; Hansen, V.

    2007-04-01

    Age hardening in industrial 7xxx alloys at the temperature 100° and 150°C up to 144 hrs, after solid solution treatments at 450° and 550°C, has been followed by measurements of Vickers hardness, scanning and transmission electron microscopy. The influence of silicon on phase and kinetic of age hardening zones and precipitates has been studied. High iron and silicon content increase the number of primary particle in the alloy. Size distribution of ɛ'-precipitates has been determined.

  19. Oxidation hardening kinetics of the rheological function G'/('/G') in asphalts

    KAUST Repository

    Juristyarini, Pramitha

    2011-07-29

    The authors used 9 asphalts oxidized at various temperatures and pressures to determine the hardening kinetics for the DSR function, an easily measured and meaningful surrogate for 15C ductility that relates well to age-related binder deterioration. For each asphalt, there is a rapid initial period that slows to a constant rate period. This constant rate period can be represented by carbonyl formation (oxidation) rate times a hardening susceptibility (HS). For the DSR function and viscosity, the HS and initial jump were pressure-but not temperature-dependent. The DSR function initial jump was relatively higher than the viscosity initial jump. © 2011 Taylor & Francis Group, LLC.

  20. The influence of strain hardening on cumulative plastic deformation in rolling and sliding line contact

    Science.gov (United States)

    Bower, A. F.; Johnson, K. L.

    THE INFLUENCE of strain hardening on the cumulative plastic deformation (ratchetting) which takes place in repeated rolling and sliding contacts has been assessed by the use of a non-linear kinematic hardening law proposed and tested by B OWER ( J. Mech. Phys. Solids37,455, 1989). Both the sub-surface flow, which occurs at low traction coefficients ( traction ( >0.25), have been investigated. Two materials have been studied: hard-drawn copper and rail steel. Good correlation was found for copper between the theory and rolling contact experiments.

  1. Radiation hardening of components and systems for nuclear rocket vehicle applications

    Science.gov (United States)

    Greenhow, W. A.; Cheever, P. R.

    1972-01-01

    The results of the analysis of the S-2 and S-4B components, although incomplete, indicate that many Saturn 5 components and subsystems, e.g., pumps, valves, etc., can be radiation hardened to meet NRV requirements by material substitution and minor design modifications. Results of these analyses include (1) recommended radiation tolerance limits for over 100 material applications; (2) design data which describes the components of each system; (3) presentation of radiation hardening examples of systems; and (4) designing radiation effects tests to supply data for selecting materials.

  2. Optimization of hardening/softening behavior of plane frame structures using nonlinear normal modes

    DEFF Research Database (Denmark)

    Dou, Suguang; Jensen, Jakob Søndergaard

    2016-01-01

    Devices that exploit essential nonlinear behavior such as hardening/softening and inter-modal coupling effects are increasingly used in engineering and fundamental studies. Based on nonlinear normal modes, we present a gradient-based structural optimization method for tailoring the hardening....../softening behavior of nonlinear mechanical systems. The iterative optimization procedure consists of calculation of nonlinear normal modes, solving an adjoint equation system for sensitivity analysis and an update of design variables using a mathematical programming tool. We demonstrate the method with examples...

  3. Neutron diffraction analysis of the microstructure of dispersion-hardening steels

    Science.gov (United States)

    Bobrikov, I. A.; Mukhametuly, B.; Balagurov, A. M.

    2016-10-01

    Neutron diffraction was employed in order to determine microdeformations in samples of stainless austenitic dispersion-hardened steels subjected to the action of high temperatures (to 700°C) during different times (up to 12 h). Experiments were conducted on a high-resolution neutron diffractometer using the timeof- flight method. The analysis performed showed systematic changes in the parameters and microdeformations of the crystal lattice. The high level of the diffractometer resolving power made it possible to reveal some important additional details of the microstructure of dispersion-hardened steels as compared to the results obtained earlier on a diffractometer with monochromatic neutron beam.

  4. Cold hardening protects cereals from oxidative stress and necrotrophic fungal pathogenesis

    Directory of Open Access Journals (Sweden)

    Pogány Miklós

    2016-01-01

    Full Text Available The effects of cold hardening of cereals on their cross-tolerance to treatments leading to oxidative stress were investigated. Long-term exposure to low non-freezing temperatures provided partial protection to wheat and barley plants from the damage caused by paraquat and hydrogen peroxide treatments. It also conferred resistance in two barley cultivars to the necrotic symptoms and growth of the fungal phytopathogen Pyrenophora teres f. teres. Pathogen-induced oxidative burst was also reduced in cold hardened plants. The possible roles of host-derived redox factors and other signaling components in the observed forms of cereal cross-tolerance are discussed.

  5. Improved technique to remove hardened sludge on top of Steam generator tube sheet

    Energy Technology Data Exchange (ETDEWEB)

    Baumgartl, R.

    2015-07-01

    Since many years the top of Steam Generator tube sheet is cleaned by high pressure water jets. In the standard process a multi-nozzle head is manipulated remote controlled inside the No tube lane. The high pressure water jets are directed between the inter-tube aisles. Inner bundle lancing enhanced the efficiency to remove hardened sludge at low flow areas above the tube sheet to a certain extent. For that the nozzle head is fed between the inner tube aisles thus reducing the work distance to a minimum. AREVA GmbH realized a hydraulic driven toothed blade to considerably raise the removal rate of the hardened sludge. (Author)

  6. Tribological behaviour of line hardening of steel U13A with Nd: YAG laser

    Directory of Open Access Journals (Sweden)

    Sagaro, R.

    1999-06-01

    Full Text Available To diminish wear in tribological systems is frequently to harden locally the load carrying areas, which are subjected to wear. A Nd:YAG laser was used for the improvement of hardness and wear resistance of steel U13A. The friction and wear characteristics of steel U13A in sliding contact against steel 65MN4 under unlubricated conditions were evaluated for conventional treatments and after laser irradiation. In addition the transformations occurring during laser treatments and the influence of laser parameters for quenching on tribological characteristics are presented. The experimental work indicates that wear resistance of steel U13A (AISI Wl 12 is several times higher then that for conventional heat treatments.

    Para disminuir el desgaste en los sistemas tribológicos frecuentemente se llevan a cabo endurecimientos localizados en aquellas áreas sometidas a esfuerzos y que están sujetas a desgaste. En el trabajo se presenta el endurecimiento y el incremento de la resistencia al desgaste del acero U13A, empleando un láser de Nd: YAG. Se evalúan las características de fricción y desgaste del acero U13A en contacto deslizante con el acero 65MN4 bajo condiciones de fricción seca para muestras con tratamientos térmicos convencionales y luego del tratamiento con láser. Se presentan además las transformaciones estructurales que tienen lugar durante el tratamiento con láser, así como la influencia de los parámetros operacionales del láser en las características tribológicas. Todo el trabajo experimental muestra un incremento de la resistencia al desgaste del acero U13A (AISI W112 con tratamiento térmico superficial con láser comparativamente con los tratamientos térmicos convencionales.

  7. The softened heat-affected zone in resistance spot welded tailor hardened boron steel: a material model for crash simulation

    NARCIS (Netherlands)

    Eller, Tom; Greve, L; Andres, M.T.; Medricky, M; Geijselaers, Hubertus J.M.; Meinders, Vincent T.; van den Boogaard, Antonius H.

    2016-01-01

    A hardness-based model for tailor hardened boron steel is presented that takes into account the softened heat-affected zone of resistance spot welds. The computational model is designed for crashworthiness simulation of fully and partially hardened components obtained by tailored tooling. Five

  8. Effect of laser surface hardening on the microstructure, hardness and residual stresses of austempered ductile iron grades

    Energy Technology Data Exchange (ETDEWEB)

    Soriano, C., E-mail: csoriano@tekniker.es [Tekniker-IK4, Manufacturing Processes Department, Avda. Otaola 20, CP-20600, Eibar (Gipuzkoa) (Spain); Leunda, J.; Lambarri, J.; Garcia Navas, V.; Sanz, C. [Tekniker-IK4, Manufacturing Processes Department, Avda. Otaola 20, CP-20600, Eibar (Gipuzkoa) (Spain)

    2011-06-01

    A study of the laser surface hardening process of two austempered ductile iron grades, with different austempering treatments has been carried out. Hardening was performed with an infrared continuous wave Nd:YAG laser in cylindrical specimens. The microstructure of the laser hardened samples was investigated using an optical microscope, microhardness profiles were measured and surface and radial residual stresses were studied by an X-ray diffractometer. Similar results were achieved for both materials. A coarse martensite with retained austenite structure was found in the treated area, resulting in a wear resistant effective layer of 0.6 mm to 1 mm with a microhardness between 650 HV and 800 HV. Compressive residual stresses have been found at the hardened area being in agreement with the microhardness and microstructural variations observed. The achieved results point out that the laser surface hardening is a suitable method for improving the mechanical properties of austempered ductile irons.

  9. The effect of initial microstructure on the final properties of press hardened 22MnB5 steels

    International Nuclear Information System (INIS)

    Järvinen, Henri; Isakov, Matti; Nyyssönen, Tuomo; Järvenpää, Martti; Peura, Pasi

    2016-01-01

    This paper addresses the relationship between initial microstructure and final properties of press hardened 22MnB5 steels. Four commercial 22MnB5 steels having different initial microstructures were investigated. An experimental press hardening equipment with a flat-die was used to investigate material behavior in the direct press hardening process. Two austenitizing treatments, 450 s and 180 s at 900 °C, were examined. Microstructural characterization with optical and scanning electron microscopes revealed a mixture of martensite and auto-tempered martensite after press hardening. Electron backscatter diffraction data of the transformed martensite was used to reconstruct grain boundary maps of parent austenite. Grain sizes of parent austenite (mean linear intercept) were measured for each material. In addition to microstructural evaluation, quasistatic and high strain rate tensile tests at strain rates of 5×10 −4 s −1 and 400 s −1 , respectively, were performed for press hardened samples. The results show that strength and uniform elongation depend on the initial microstructure of the 22MnB5 steel, when parameters typical to the direct press hardening process are used. Parent austenite grain size was shown to influence the morphology of the transformed martensite, which in turn affects the strength and uniform elongation after press hardening. The tensile properties of the press hardened materials are almost strain rate independent in the studied strain rate range. The obtained results can be used to optimize the properties of 22MnB5 steels in the direct press hardening process. In addition, the here revealed connection between the parent austenite grain size and final steel properties should be taken into account in the development of new press hardening steel grades for automotive industry.

  10. Co speciation in hardened cement paste: a macro- and micro-spectroscopic investigation.

    Science.gov (United States)

    Vespa, M; Dähn, R; Grolimund, D; Wieland, E; Scheidegger, A M

    2007-03-15

    Cement-based materials play an important role in multi-barrier concepts developed worldwide for the safe disposal of hazardous and radioactive wastes. Cement is used to condition and stabilize the waste materials and to construct the engineered barrier systems (container, backfill and liner materials) of repositories for radioactive waste. In this study, Co uptake by hardened cement paste (HCP) has been investigated with the aim of improving our understanding of the immobilization process of heavy metals in cement on the molecular level. X-ray-absorption spectroscopy (XAS) on powder material (bulk-XAS) was used to determine the local environment of Co in cement systems. Bulk-XAS investigations were complemented with micro-beam investigations to probe the inherent microscale heterogeneity of cement by using micro-X-ray-fluorescence (micro-XRF) and micro-XAS. Micro-XRF was used to gain information on the spatial heterogeneity of the Co distribution, whereas micro-XAS was employed to determine the speciation of Co on the microscale. The Co-doped HCP samples hydrated for time-scales from 1 hour up to 1 year were prepared under normal atmosphere, to simulate similar conditions as for waste packages. To investigate the role of oxygen, further samples were prepared in the absence of oxygen. The study showed that, for the samples prepared in air, Co(II) is oxidized to Co(III) after 1 hour of hydration time. Moreover, the relative amount of Co(III) increases with increasing hydration time. The study further revealed that Co(II) is predominately present as a Co-hydroxide-like phase and/or Co-phyllosilicates, whereas Co(III) tends to be incorporated into a CoOOH-like phase and/or Co-phyllomanganates. In contrast to samples prepared in air, XAS experiments with samples prepared in the absence of oxygen revealed solely the presence of Co(II). This finding indicates that oxygen plays an important role for Co oxidation in cement. Furthermore, the study suggests that Co

  11. Distinguishing between hydrated, partially hydrated or unhydrated clinker in hardened concrete using microscopy

    NARCIS (Netherlands)

    Valcke, S.L.A.; Rooij, M.R. de; Visser, J.H.M.; Nijland, T.G.

    2010-01-01

    Hydration of clinker particles is since long a topic of interest in both designing and optimizing cement composition and its quantity used in concrete. The interest for carefully observing and also quantifying the type or stage of clinker hydration in hardened cement paste is twofold. Firstly, the

  12. Finite-Element Simulation of Conventional and High-Speed Peripheral Milling of Hardened Mold Steel

    Science.gov (United States)

    Tang, D. W.; Wang, C. Y.; Hu, Y. N.; Song, Y. X.

    2009-12-01

    A finite-element model (FEM) with the flow stress and typical fracture is used to simulate a hard machining process, which before this work could not adequately represent the constitutive behavior of workpiece material that is usually heat treated to hardness levels above 50 Rockwell C hardness (HRC). Thus, a flow stress equation with a variation in hardness is used in the computer simulation of hard machining. In this article, the influence of the milling speed on the cutting force, chip morphology, effective stress, and cutting temperature in the deformation zones of both conventional and high-speed peripheral milling hardened mold steel is systematically studied by finite-element analysis (FEA). By taking into consideration the importance of material characteristics during the milling process, the similar Johnson-Cook’s constitutive equation with hardened mold steel is introduced to the FEM to investigate the peripheral milling of hardened mold steel. In comparison with the experimental data of the cutting force at various cutting speeds, the simulation result is identical with the measured data. The results indicate that the model can be used to accurately predict the behavior of hardened mold steel in both conventional and high-speed milling.

  13. Design and characterization of novel precipitation hardenable high Cr Ni-based superalloys

    DEFF Research Database (Denmark)

    Bihlet, Uffe; Dahl, Kristian Vinter; Somers, Marcel A. J.

    2012-01-01

    in the aircraft industry in the 1960’s. Five powder metallurgical Ni-based superalloys containing 35-45 wt % Cr and 4-6 wt % Nb were designed with the aim of maintaining the hardening mechanism found in Alloy 718, while drastically increasing the hot corrosion resistance. The alloys were manufactured...

  14. Characterization and Strain-Hardening Behavior of Friction Stir-Welded Ferritic Stainless Steel

    Science.gov (United States)

    Sharma, Gaurav; Dwivedi, Dheerendra Kumar; Jain, Pramod Kumar

    2017-12-01

    In this study, friction stir-welded joint of 3-mm-thick plates of 409 ferritic stainless steel (FSS) was characterized in light of microstructure, x-ray diffraction analysis, hardness, tensile strength, ductility, corrosion and work hardening properties. The FSW joint made of ferritic stainless steel comprises of three distinct regions including the base metal. In stir zone highly refined ferrite grains with martensite and some carbide precipitates at the grain boundaries were observed. X-ray diffraction analysis also revealed precipitation of Cr23C6 and martensite formation in heat-affected zone and stir zone. In tensile testing of the transverse weld samples, the failure eventuated within the gauge length of the specimen from the base metal region having tensile properties overmatched to the as-received base metal. The tensile strength and elongation of the longitudinal (all weld) sample were found to be 1014 MPa and 9.47%, respectively. However, in potentiodynamic polarization test, the corrosion current density of the stir zone was highest among all the three zones. The strain-hardening exponent for base metal, transverse and longitudinal (all weld) weld samples was calculated using various equations. Both the transverse and longitudinal weld samples exhibited higher strain-hardening exponents as compared to the as-received base metal. In Kocks-Mecking plots for the base metal and weld samples at least two stages of strain hardening were observed.

  15. Influence of temperature on autogenous deformation and relative humidity change in hardening cement paste

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede; Hansen, Per Freiesleben

    1999-01-01

    This paper deals with autogenous deformation and autogenous relative humidity change (RH change) in hardening cement paste. Theoretical considerations and experimental data are presented, which elucidate the influence of temperature on these properties. This is an important subject in the control...

  16. Stability and motion of low angle dislocation boundaries in precipitation hardened crystals

    Czech Academy of Sciences Publication Activity Database

    Holec, David; Dlouhý, Antonín

    2005-01-01

    Roč. 482, - (2005), s. 159-162 ISSN 0255-5476 Institutional research plan: CEZ:AV0Z20410507 Keywords : Low angle dislocation boundary * precipitation hardening * dislocation motion Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.399, year: 2005

  17. Use of pre-irradiated commercial MOSFETs in a power supply hardened to withstand gamma radiation

    International Nuclear Information System (INIS)

    Marceau, M.; Huillet, H.

    1999-01-01

    This paper describes the approach used to design a hardened power supply capable of operating to a total gamma irradiation dose of 10 kGy(Si). Pre-irradiation of power MOSFETs proved to be necessary, and the paper also discusses the effects of this treatment. (authors)

  18. Self-healing behavior of strain hardening cementitious composites incorporating local waste materials

    NARCIS (Netherlands)

    Qian, S.; Zhou, J.; Rooij, M.R. de; Schlangen, E.; Ye, G.; Breugel, K. van

    2009-01-01

    The self-healing behavior of a series of pre-cracked fiber reinforced strain hardening cementitious composites incorporating blast furnace slag (BFS) and limestone powder (LP) with relatively high water/binder ratio is investigated in this paper, focusing on the recovery of its deflection capacity.

  19. CMOS/SOS 4k Rams hardened to 100 Krads (s:)

    International Nuclear Information System (INIS)

    Napoli, L.S.; Heagerty, W.F.; Smeltzer, R.K.; Yeh, J.L.

    1982-01-01

    Two CMOS/SOS 4K memories were fabricated with a recently developed, hardened SOS process. Memory functionality after radiation doses well in excess of 100 Krads(Si) was demonstrated. The critical device processing steps were identified. The radiationinduced failure mode of the memories is understood in terms of the circuit organization and the radiation behavior of the individual transistors in the memories

  20. Study on the Strain Hardening Behaviors of TWIP/TRIP Steels

    Science.gov (United States)

    Huang, T. T.; Dan, W. J.; Zhang, W. G.

    2017-10-01

    Due to the complex coupling of twinning-induced plasticity (TWIP), transformation-induced plasticity (TRIP), and dislocation glide in TWIP/TRIP steels, it is difficult as well as essential to build a comprehensive strain hardening model to describe the interactions between different deformation mechanisms ( i.e., deformation twinning, martensitic transformation, and dislocation glide) and the resulted strain hardening behaviors. To address this issue, a micromechanical model is established in this paper to predict the deformation process of TWIP/TRIP steels considering both TWIP and TRIP effects. In the proposed model, the generation of deformation twinning and martensitic transformation is controlled by the stacking fault energy (SFE) of the material. In the thermodynamic calculation of SFE, deformation temperature, chemical compositions, microstrain, and temperature rise during deformation are taken into account. Varied by experimental results, the developed model can predict the stress-strain response and strain hardening behaviors of TWIP/TRIP steels precisely. In addition, the improved strength and enhanced strain hardening in Fe-Mn-C TWIP/TRIP steels due to the increased carbon content is also analyzed, which consists with literature.

  1. Direct assessment of tensile stress-crack opening behavior of Strain Hardening Cementitious Composites (SHCC)

    DEFF Research Database (Denmark)

    Pereira, Eduardo B.; Fischer, Gregor; Barros, Joaquim A.O.

    2012-01-01

    The process of designing Strain Hardening Cementitious Composites (SHCC) is driven by the need to achieve certain performance parameters in tension. These are typically the pseudo-strain hardening behavior and the ability to develop multiple cracks. The assessment of the tensile load-deformation ......The process of designing Strain Hardening Cementitious Composites (SHCC) is driven by the need to achieve certain performance parameters in tension. These are typically the pseudo-strain hardening behavior and the ability to develop multiple cracks. The assessment of the tensile load......-deformation behavior of these materials is therefore of great importance and is frequently carried out by characterizing the material tensile stress–strain behavior. In this paper an alternative approach to evaluate the tensile performance of SHCC is investigated. The behavior of the material in tension is studied...... at the level of a single crack. The derived tensile stress-crack opening behavior is utilized to analyze and compare the influence of various composite parameters on the resulting tensile behavior. The deformations occurring during tensile loading are furthermore examined using a digital image...

  2. Beam-hardening correction in CT based on basis image and TV model

    International Nuclear Information System (INIS)

    Li Qingliang; Yan Bin; Li Lei; Sun Hongsheng; Zhang Feng

    2012-01-01

    In X-ray computed tomography, the beam hardening leads to artifacts and reduces the image quality. It analyzes how beam hardening influences on original projection. According, it puts forward a kind of new beam-hardening correction method based on the basis images and TV model. Firstly, according to physical characteristics of the beam hardening an preliminary correction model with adjustable parameters is set up. Secondly, using different parameters, original projections are operated by the correction model. Thirdly, the projections are reconstructed to obtain a series of basis images. Finally, the linear combination of basis images is the final reconstruction image. Here, with total variation for the final reconstruction image as the cost function, the linear combination coefficients for the basis images are determined according to iterative method. To verify the effectiveness of the proposed method, the experiments are carried out on real phantom and industrial part. The results show that the algorithm significantly inhibits cup and strip artifacts in CT image. (authors)

  3. Effect of hardness and composition gradients on Barkhausen emission in case hardened steel

    International Nuclear Information System (INIS)

    Blaow, M.; Evans, J.T.; Shaw, B.A.

    2006-01-01

    The effect of gradients in hardness, structure and composition in the surface layers on magnetic Barkhausen noise (MBN) was investigated in two widely used low alloy steels. One material was case hardened by induction hardening. The other was case carburised. Similar hardness profiles were produced by the two treatments. It was found that the variation in structure and hardness through the case in the induction-hardened steel had a minor effect on the MBN profile. In contrast, the inhomogeneity in the case-carburised material showed up clearly. This took the form of a broadened or two-peak MBN profile. When the surface layer containing the case was removed by etching, the broadened profile was replaced by a profile with a single peak. It is concluded that the shape and position of the MBN profile is significantly affected when a gradient in microstructure is induced by a gradient in carbon content. On the other hand, a gradient in microstructure induced by heat treatment with a constant carbon level has much less affect on the MBN profile for the induction-hardened steel

  4. An Age-Hardening Model for Al-Mg-Si Alloys Considering Needle-Shaped Precipitates

    NARCIS (Netherlands)

    Bahrami, A.; Miroux, A.; Sietsma, J.

    2012-01-01

    In the present study, an age-hardening model for Al-Mg-Si alloys was developed considering cylindrical morphology with constant aspect ratio for precipitates. It is assumed that the precipitate distribution during underaging is controlled by simultaneous nucleation and growth, and after peak age,

  5. Alloy hardening of a smectic A liquid crystal doped with gold nanoparticles

    Czech Academy of Sciences Publication Activity Database

    Oswald, P.; Milette, J.; Relaix, S.; Reven, L.; Dequidt, A.; Lejček, Lubor

    2013-01-01

    Roč. 103, AUG (2013), "46004-p1"-"46004-p6" ISSN 0295-5075 Institutional support: RVO:68378271 Keywords : smectic A liquid crystals * gold nanoparticles * edge dislocation * precipitation hardening Subject RIV: BK - Fluid Dynamics Impact factor: 2.269, year: 2013

  6. Electron beam hardening of lacquer coatings in the industrial fabrication of doors

    International Nuclear Information System (INIS)

    Haering, Ernst von.

    1975-01-01

    The method used at the SVEDEX plant (Netherlands) is presented. A comparison is made between the costs of lacquering using the conventional method and the electron beam hardening method (thickness of lacquer coating, energy sources, pollution). The apparatus used and the irradiation technology are described

  7. A brief review of cavity swelling and hardening in irradiated copper and copper alloys

    International Nuclear Information System (INIS)

    Zinkle, S.J.

    1990-01-01

    The literature on radiation-induced swelling and hardening in copper and its alloy is reviewed. Void formation does not occur during irradiation of copper unless suitable impurity atoms such as oxygen or helium are present. Void formation occurs for neutron irradiation temperatures of 180 to 550 degree C, with peak swelling occurring at ∼320 degree C for irradiation at a damage rate of 2 x 10 -7 dpa/s. The post-transient swelling rate has been measured to be ∼0.5%/dpa at temperatures near 400 degree C. Dispersion-strengthened copper has been found to be very resistant to void swelling due to the high sink density associated with the dispersion-stabilized dislocation structure. Irradiation of copper at temperatures below 400 degree C generally causes an increase in strength due to the formation of defect clusters which inhibit dislocation motion. The radiation hardening can be adequately described by Seeger's dispersed barrier model, with a barrier strength for small defect clusters of α ∼ 0.2. The radiation hardening apparently saturates for fluences greater than ∼10 24 n/m 2 during irradiation at room temperature due to a saturation of the defect cluster density. Grain boundaries can modify the hardening behavior by blocking the transmission of dislocation slip bands, leading to a radiation- modified Hall-Petch relation between yield strength and grain size. Radiation-enhanced recrystallization can lead to softening of cold-worked copper alloys at temperatures above 300 degree C

  8. Microstructure and transport phenomena in visco-elastic modelling of hardening cementitious materials

    NARCIS (Netherlands)

    Van der Ham, H.W.M.

    2011-01-01

    Since the durability depends, among other things, on the quality of the concrete and presence of cracks, it is necessary to calculate the probability of cracking in hardening concrete as reliable as possible in case of durability predictions. In this thesis, it is investigated how the accuracy of

  9. Computer simulation and radiation hardening of power devices to protect against failures induced by heavy ions

    International Nuclear Information System (INIS)

    Lorfevre, E.; Detcheverry, C.; Sudre, C.; Bruguier, G.; Palau, J.M.; Roubaud, F.

    1997-01-01

    Power devices such as MOSFETSs and IGBTs, include parasitic structures that can give rise to destructive failures such as breakdown and latch-up. To determine a suitable strategy for device radiation hardening, simulation software like MEDICI-2D can be used to model the effects of technological modifications and device parameters that are difficult to measure experimentally. (authors)

  10. Bake hardening of ultra-fine grained low carbon steel produced by constrained groove pressing

    International Nuclear Information System (INIS)

    Alihosseini, H.; Dehghani, K.

    2012-01-01

    Highlights: ► BH of UFG low carbon steel sheets was studied. ► Three passes of CGP are used for producing of UFG sheets. ► Maximum BH was achieved to the UFG specimen pre-strained 8% by baking at 250 °C. - Abstract: In the present work, the bake hardening of ultra-fine grained low carbon steel was compared with that of its coarse-grain counterpart. The ultra-fine grained sheets were produced by applying three passes of constrained groove pressing resulting the grains of 260–270 nm. The microstructure of ultra-fine grain specimens were characterized using electron back-scatter diffraction technique. Then, the bake hardenability of ultra-fine grain and coarse-grain samples were compared by pre-straining to 4, 6 and 8% followed by baking at 150 °C and 250 °C for 20 min. The results show that in case of baking at 250 °C, there was an increase about 108%, 93%, and 72% in the bake hardening for 4%, 6% and 8% pre-strain, respectively. As for baking at 150 °C, these values were 170%, 168%, and 100%, respectively for 4%, 6% and 8% pre-strain. The maximum in bake hardenability (103 MPa) and final yield stress (563 MPa) were pertaining to the ultra-fine grain specimen pre-strained 8% followed by baking at 250 °C.

  11. Effect of Fibers and Filler Types on Fresh and Hardened Properties of Self-Compacting Concrete

    Directory of Open Access Journals (Sweden)

    Saeed K. Rejeb* , Majid Kh . N. Ayad A. M.

    2014-04-01

    Full Text Available This paper deals with studying the fresh and hardened properties of self-compacting concrete, by using three types of filler (silica fume, clinker powder & lime stone powder, and two types of fibers (steel & glass fibers with volume fractions of (0.5% and (0.1% respectively. For each type of fillers, the fresh properties are measured by using Slump test, J- ring and V- funnel, while hardened properties include the compressive strength, splitting tensile strength and flexural strength. The results show that adding fibers to the self-compacting concrete (SCC well reduces the workability and improves the hardened properties. Also, the study concluded that better workability is obtained by using (lime stone, silica fume and clinker powder as fillers, respectively. While the higher hardened properties are gained by using silica fume were rather than those of other types of fillers 

  12. Hot tensile properties and strain hardening behaviour of Super 304HCu stainless steel

    Directory of Open Access Journals (Sweden)

    M. Vinoth Kumar

    2017-04-01

    Full Text Available Super 304HCu austenitic stainless steel containing 2.3–3 (wt.% of Cu is mainly used in superheaters and reheaters tubing of ultra super critical boilers which operates over 600 °C of steam temperature. Tensile tests were carried out on Super 304HCu, using nominal strain rate of 1 × 10−3 s−1, at room temperature, 550 °C, 600 °C and 650 °C. The tensile strength and elongation were found to decrease with increase in test temperature. The stress strain curves were fitted using Hollomon equation to determine the strain hardening exponent value. Differential Crussard–Jaoul (C–J analysis of the tensile curve is used to determine the variation in strain hardening exponent. Kocks–Mecking (K–M type plots were used to determine the stages of strain hardening during tensile loading of the specimen. The strain hardening capacity of the Super 304HCu is found to decrease with increase in test temperature.

  13. Friction and wear behaviour of ceramic-hardened steel couples under reciprocating sliding motion

    NARCIS (Netherlands)

    He, Y.; Winnubst, Aloysius J.A.; Schipper, Dirk J.; Bakker, P.M.V.; Bakker, P.M.V.; Burggraaf, Anthonie; Burggraaf, A.J.; Verweij, H.

    1995-01-01

    The friction and wear behaviour of ZrO2-Y203, ZrO2-Y203-CeO2 and ZrO2-A1203 composite ceramics against hardened steel AISI-52100 were investigated using a pin on plate configuration under reciprocating motion. The reproducibility of the results was examined in this configuration. Wear

  14. Radiation-hardened I2L 8*8 multiplier circuit

    International Nuclear Information System (INIS)

    Doyle, B.R.; Kreps, S.A.; Van Vonno, N.W.; Lake, G.W.

    1979-01-01

    Development of improved Substrate Fed I 2 L (SFL) processing has been combined with geometry and fanout constraints to design a radiation hardened LSI 8.8 Multiplier. This study describes details of the process and circuit design and gives resultant electrical and radiation test performance

  15. Radiation hardenable impregnating agents for the consolidating conservation of wooden objects

    International Nuclear Information System (INIS)

    Schaudy, R.

    1985-01-01

    Radiation hardenable impregnating agents offer some advantages over the conventional agents. At the author's institution objects up to 110 cm length can be impregnated for conservation. More than 200 monomers and resins have been investigated. The procedure of impregnation is outlined and some kinds of wooden objects conserved in this way listed. (G.W.)

  16. Metal Artifact Reduction for Polychromatic X-ray CT Based on a Beam-Hardening Corrector.

    Science.gov (United States)

    Park, Hyoung Suk; Hwang, Dosik; Seo, Jin Keun

    2016-02-01

    This paper proposes a new method to correct beam hardening artifacts caused by the presence of metal in polychromatic X-ray computed tomography (CT) without degrading the intact anatomical images. Metal artifacts due to beam-hardening, which are a consequence of X-ray beam polychromaticity, are becoming an increasingly important issue affecting CT scanning as medical implants become more common in a generally aging population. The associated higher-order beam-hardening factors can be corrected via analysis of the mismatch between measured sinogram data and the ideal forward projectors in CT reconstruction by considering the known geometry of high-attenuation objects. Without prior knowledge of the spectrum parameters or energy-dependent attenuation coefficients, the proposed correction allows the background CT image (i.e., the image before its corruption by metal artifacts) to be extracted from the uncorrected CT image. Computer simulations and phantom experiments demonstrate the effectiveness of the proposed method to alleviate beam hardening artifacts.

  17. The effect of dynamic aging on the strain hardening rate of titanium

    International Nuclear Information System (INIS)

    Monteiro, S.N.; Reed-Hill, R.E.

    1974-01-01

    A study is made of the effect due to the interaction of solute atoms with mobile dislo cations, known as dynamic aging on the strain hardening characteristics of titanium between 150 and 477K. The results obtained with commercially pure titanium are compared with those obtained using high - purity titanium in order to evaluate the extent of effect [pt

  18. An alternative approach to estimate the W/C ratio of hardened concrete using image analysis

    NARCIS (Netherlands)

    Valcke, S.; Nijland, T.G.; Larbi, J.A.

    2009-01-01

    The water cement (w/c) ratio is a typical quality parameter for concrete. The NT Build 361 Nordtest method is a standard for estimating the w/c ratio in hardened concrete and is based on the relationship between the ilc ratio and the capillary porosity in the cement paste. The latter can be

  19. High temperature, radiation hardened electronics for application to nuclear power plants

    International Nuclear Information System (INIS)

    Gover, J.E.

    1980-01-01

    Electronic circuits were developed and built at Sandia for many aerospace and energy systems applications. Among recent developments were high temperature electronics for geothermal well logging and radiation hardened electronics for a variety of aerospace applications. Sandia has also been active in technology transfer to commercial industry in both of these areas

  20. Work hardening induced by martensite during transformation-induced plasticity in plain carbon steel

    International Nuclear Information System (INIS)

    Moat, R.J.; Zhang, S.Y.; Kelleher, J.; Mark, A.F.; Mori, T.; Withers, P.J.

    2012-01-01

    Transformation-induced plasticity (TRIP) steels are becoming increasingly exploited for industrial applications because they show high strength and high uniform elongation (ductility). Despite this interest, the relative contributions of the various strengthening and straining mechanisms are often poorly understood. In this study, neutron diffraction is employed to quantify the contribution of different mechanisms to ductility and work hardening for a 0.25 wt.% C steel. Differences in stress–strain response at different temperatures are related to the extent of the transformation of metastable austenite into martensite during deformation. At room temperature (RT) the transformation of austenite occurs gradually with straining, while at −50 °C the transformation occurs almost from the onset of loading. The associated transformation strain is reduced, comprising nearly half the total strain, lowering the apparent elastic modulus and explaining the relatively low work hardening compared to RT straining. By contrast, deformation at RT after pre-straining at −50 °C results in larger work hardening than for solely RT straining due to the higher martensite levels introduced at −50 °C. This is due to composite load transfer to the strong constituent from the soft matrix. The extent of the transformation is quantified as a function of strain at both temperatures as well as its effect on the work hardening and elongation.

  1. Update on radiation-hardened microcomputers for robotics and teleoperated systems

    International Nuclear Information System (INIS)

    Sias, F.R. Jr.; Tulenko, J.S.

    1993-01-01

    Since many programs sponsored by the Department of Defense are being canceled, it is important to select carefully radiation-hardened microprocessors for projects that will mature (or will require continued support) several years in the future. At the present time there are seven candidate 32-bit processors that should be considered for long-range planning for high-performance radiation-hardened computer systems. For Department of Energy applications it is also important to consider efforts at standardization that require the use of the VxWorks operating system and hardware based on the VMEbus. Of the seven processors, one has been delivered and is operating and other systems are scheduled to be delivered late in 1993 or early in 1994. At the present time the Honeywell-developed RH32, the Harris RH-3000 and the Harris RHC-3000 are leading contenders for meeting DOE requirements for a radiation-hardened advanced 32-bit microprocessor. These are all either compatible with or are derivatives of the MIPS R3000 Reduced Instruction Set Computer. It is anticipated that as few as two of the seven radiation-hardened processors will be supported by the space program in the long run

  2. Influence of plastic deformation on low temperature surface hardening of stainless steel by gaseous nitriding

    DEFF Research Database (Denmark)

    Bottoli, Federico; Winther, Grethe; Christiansen, Thomas Lundin

    2015-01-01

    This article addresses an investigation of the influence of plastic deformation on low temperature surface hardening by gaseous nitriding of three commercial austenitic stainless steels: AISI 304, EN 1.4369 and Sandvik Nanoflex® with various degrees of austenite stability. The materials were plas...

  3. Hardening Unmanned Aerial Systems Against High Power Microwave Threats in Support of Forward Operations

    Science.gov (United States)

    2017-04-01

    price to harden UAS against HPM, while decreasing, is still significant enough at the time of this study to be given due consideration. Therefore...sensitive electronics across the spectrum of multi-domain operations. Developing such practical, cost- conscious solutions ahead of anticipated threats

  4. Effects of the Strain Rate Sensitivity and Strain Hardening on the Saturated Impulse of Plates

    Directory of Open Access Journals (Sweden)

    Ling Zhu

    Full Text Available Abstract This paper studies the stiffening effects of the material strain rate sensitivity and strain hardening on the saturated impulse of elastic, perfectly plastic plates. Finite element (FE code ABAQUS is employed to simulate the elastoplastic response of square plates under rectangular pressure pulse. Rigid-plastic analyses for saturated impulse, which consider strain rate sensitivity and strain hardening, are conducted. Satisfactory agreement between the finite element models (FEM and predictions of the rigid-plastic analysis is obtained, which verifies that the proposed rigid-plastic methods are effective to solve the problem including strain rate sensitivity and strain hardening. The quantitative results for the scale effect of the strain rate sensitivity are given. The results for the stiffening effects suggest that two general stiffening factors n 1 and n 2, which characterizes the strain rate sensitivity and strain hardening effect, respectively can be defined. The saturated displacement is inversely proportional to the stiffening factors (i.e. n 1 and n 2 and saturated impulse is inversely proportional to the square roots of the stiffening factors (i.e. n 1 and n 2. Formulae for displacement and saturated impulse are proposed based on the empirical analysis.

  5. Work hardening behavior of the extruded and equal-channel angularly pressed Mg–Li–Zn alloys under tensile and shear deformation modes

    Energy Technology Data Exchange (ETDEWEB)

    Karami, M.; Mahmudi, R., E-mail: mahmudi@ut.ac.ir

    2014-06-01

    The flow and work hardening behaviors of extruded and equal-channel angularly pressed (ECAPed) Mg–6Li–1Zn (LZ61) and Mg–12Li–1Zn (LZ121) alloys were studied by tensile and shear punch testing methods. It was shown that the Kocks–Mecking type plots for tensile and shear deformation of both alloys, exhibited similar work hardening (WH) stages in both extruded and ECAPed conditions. WH rates were found to be lower for the ECAPed materials, due to a reasonably uniform and well-refined microstructure. In the case of hcp LZ61 alloy, textural studies showed that the extruded fiber-type texture was replaced by a typical ECAP texture, in which basal planes rotated about 45° to the extrusion axis. This was found to be responsible for the lower tensile strength and higher shear strength in the ECAPed material, as compared to the extruded condition. For the bcc LZ121 alloy, it was observed that the grain refinement achieved after ECAP increases the strength and ductility in both tensile and shear deformation, compared with those of extruded condition. Stage II of the Kocks–Mecking plot in both shear and tensile deformation of LZ121 was eliminated most likely due to stacking fault energy improvement caused by higher Li content of the Mg lattice structure. The shear punch testing (SPT) method was found to yield the flow and WH curves similar to those obtained in tensile testing.

  6. Thermal hardening of saturated clays. Application to underground storage of radioactive wastes

    International Nuclear Information System (INIS)

    Picard, Jean-Marc

    1994-01-01

    Saturated clays submitted to constant mechanical loading and slow temperature increase frequently undergo irreversible contractions. This phenomena is described here by means of a change of plastic limits induced by temperature only, called thermal hardening. Constitutive laws adapted to this kind of plastic behaviour can be formulated within a general framework that satisfies thermodynamical principles. It shows that this coupling results from the presence of a latent heat during the isothermal hardening of plastic limits. A thermomechanical extension of Cam Clay model is then proposed and used in the analysis of laboratory thermomechanical tests performed on clay materials. Making use of tests already published, we show the adequacy of the concept of thermal hardening for clay behaviour. Some clay from deep geological formation considered for the disposal of radioactive waste exhibit thermal hardening in laboratory tests. The consequences for the underground storage facilities during the thermal loading created by the waste are investigated by means of in situ tests as well as numerical computation. The measurement around a heating probe buried in the clay mass demonstrate the significance of thermo-hydro-mechanical couplings. An accurate understanding of in situ measurements is achieved by means of numerical modeling in which the interaction between the various loading of the tests (excavation, pore pressure seepage, and heating) is carefully taken into account. Thermal hardening of the clay appears to be of little influence in these in situ tests. On the other hand, the magnitude of thermo-hydro-mechanical couplings observed in situ are higher than might have been expected from laboratory tests. A more accurate prediction is obtained if one takes into account the more stiffer behaviour of clays when they are subjected to small deformations. (authors)

  7. Hardening of ODS ferritic steels under irradiation with high-energy heavy ions

    Science.gov (United States)

    Ding, Z. N.; Zhang, C. H.; Yang, Y. T.; Song, Y.; Kimura, A.; Jang, J.

    2017-09-01

    Influence of the nanoscale oxide particles on mechanical properties and irradiation resistance of oxide-dispersion-strengthened (ODS) ferritic steels is of critical importance for the use of the material in fuel cladding or blanket components in advanced nuclear reactors. In the present work, impact of structures of oxide dispersoids on the irradiation hardening of ODS ferritic steels was studied. Specimens of three high-Cr ODS ferritic steels containing oxide dispersoids with different number density and average size were irradiated with high-energy Ni ions at about -50 °C. The energy of the incident Ni ions was varied from 12.73 MeV to 357.86 MeV by using an energy degrader at the terminal so that a plateau of atomic displacement damage (∼0.8 dpa) was produced from the near surface to a depth of 24 μm in the specimens. A nanoindentor (in constant stiffness mode with a diamond Berkovich indenter) and a Vickers micro-hardness tester were used to measure the hardeness of the specimens. The Nix-Gao model taking account of the indentation size effect (ISE) was used to fit the hardness data. It is observed that the soft substrate effect (SSE) can be diminished substantially in the irradiated specimens due to the thick damaged regions produced by the Ni ions. A linear correlation between the nano-hardeness and the micro-hardness was found. It is observed that a higher number density of oxide dispersoids with a smaller average diameter corresponds to an increased resistance to irradiation hardening, which can be ascribed to the increased sink strength of oxides/matrix interfaces to point defects. The rate equation approach and the conventional hardening model were used to analyze the influence of defect clusters on irradiation hardening in ODS ferritic steels. The numerical estimates show that the hardening caused by the interstitial type dislocation loops follows a similar trend with the experiment data.

  8. Press-hardening of zinc coated steel - characterization of a new material for a new process

    Science.gov (United States)

    Kurz, T.; Larour, P.; Lackner, J.; Steck, T.; Jesner, G.

    2016-11-01

    Press-hardening of zinc-coated PHS has been limited to the indirect process until a pre-cooling step was introduced before the hot forming to prevent liquid metal embrittlement. Even though that's only a minor change in the process itself it does not only eliminate LME, but increases also the demands on the base material especially in terms of hardenability or phase transformations at temperatures below 700 °C in general. This paper deals with the characterization of a modified zinc-coated material for press-hardening with pre-cooling that assures a robust process. The pre-cooling step itself and especially the transfer of the blank in the hot-forming die is more demanding than the standard 22MnB5 can stand to ensure full hardenability. Therefore the transformation behavior of the modified material is shown in CCT and TTT diagrams. Of the same importance are the changed hot forming temperature and flow curves for material at lower temperatures than typically used in direct hot forming. The resulting mechanical properties after hardening from tensile testing and bending tests are shown in detail. Finally some results from side impact crash tests and correlations of the findings with mechanical properties such as fracture elongation, tensile strength, VDA238 bending angle at maximum force as well as postuniform bending slope are given as well. Fracture elongation is shown to be of little help for damage prediction in side impact crash. Tensile strength and VDA bending properties enable however some accurate prediction of the PHS final damage behavior in bending dominated side impact load case.

  9. Radiation hardening of optical fibers and fiber sensors for space applications: recent advances

    Science.gov (United States)

    Girard, S.; Ouerdane, Y.; Pinsard, E.; Laurent, A.; Ladaci, A.; Robin, T.; Cadier, B.; Mescia, L.; Boukenter, A.

    2017-11-01

    In these ICSO proceedings, we review recent advances from our group concerning the radiation hardening of optical fiber and fiber-based sensors for space applications and compare their benefits to state-of-the-art results. We focus on the various approaches we developed to enhance the radiation tolerance of two classes of optical fibers doped with rare-earths: the erbium (Er)-doped ones and the ytterbium/erbium (Er/Yb)-doped ones. As a first approach, we work at the component level, optimizing the fiber structure and composition to reduce their intrinsically high radiation sensitivities. For the Erbium-doped fibers, this has been achieved using a new structure for the fiber that is called Hole-Assisted Carbon Coated (HACC) optical fibers whereas for the Er/Ybdoped optical fibers, their hardening was successfully achieved adding to the fiber, the Cerium element, that prevents the formation of the radiation-induced point defects responsible for the radiation induced attenuation in the infrared part of the spectrum. These fibers are used as part of more complex systems like amplifiers (Erbium-doped Fiber Amplifier, EDFA or Yb-EDFA) or source (Erbium-doped Fiber Source, EDFS or Yb- EDFS), we discuss the impact of using radiation-hardened fibers on the system radiation vulnerability and demonstrate the resistance of these systems to radiation constraints associated with today and future space missions. Finally, we will discuss another radiation hardening approach build in our group and based on a hardening-by-system strategy in which the amplifier is optimized during its elaboration for its future mission considering the radiation effects and not in-lab.

  10. Ultrasonic sound speed of hydrating calcium sulphate hemihydrate; part 1, the calculation of sound speed of slurries and hardened porous material

    NARCIS (Netherlands)

    de Korte, A.C.J.; Brouwers, Jos

    2011-01-01

    This article focuses on the computation of the sound velocity through slurries and hardened products. The purpose is to use the sound velocity to quantify the composition of the fresh slurry as well as the hardening and hardened - porous - material. Therefore the volumetric models for hydration of

  11. Effect of beam hardening on transmural myocardial perfusion quantification in myocardial CT imaging

    Science.gov (United States)

    Fahmi, Rachid; Eck, Brendan L.; Levi, Jacob; Fares, Anas; Wu, Hao; Vembar, Mani; Dhanantwari, Amar; Bezerra, Hiram G.; Wilson, David L.

    2016-03-01

    The detection of subendocardial ischemia exhibiting an abnormal transmural perfusion gradient (TPG) may help identify ischemic conditions due to micro-vascular dysfunction. We evaluated the effect of beam hardening (BH) artifacts on TPG quantification using myocardial CT perfusion (CTP). We used a prototype spectral detector CT scanner (Philips Healthcare) to acquire dynamic myocardial CTP scans in a porcine ischemia model with partial occlusion of the left anterior descending (LAD) coronary artery guided by pressure wire-derived fractional flow reserve (FFR) measurements. Conventional 120 kVp and 70 keV projection-based mono-energetic images were reconstructed from the same projection data and used to compute myocardial blood flow (MBF) using the Johnson-Wilson model. Under moderate LAD occlusion (FFR~0.7), we used three 5 mm short axis slices and divided the myocardium into three LAD segments and three remote segments. For each slice and each segment, we characterized TPG as the mean "endo-to-epi" transmural flow ratio (TFR). BH-induced hypoenhancement on the ischemic anterior wall at 120 kVp resulted in significantly lower mean TFR value as compared to the 70 keV TFR value (0.29+/-0.01 vs. 0.55+/-0.01 p<1e-05). No significant difference was measured between 120 kVp and 70 keV mean TFR values on segments moderately affected or unaffected by BH. In the entire ischemic LAD territory, 120 kVp mean endocardial flow was significantly reduced as compared to mean epicardial flow (15.80+/-10.98 vs. 40.85+/-23.44 ml/min/100g; p<1e-04). At 70 keV, BH was effectively minimized resulting in mean endocardial MBF of 40.85+/-15.3407 ml/min/100g vs. 74.09+/-5.07 ml/min/100g (p=0.0054) in the epicardium. We also found that BH artifact in the conventional 120 kVp images resulted in falsely reduced MBF measurements even under non-ischemic conditions.

  12. Analysis of the Effect of Cooling Intensity Under Volume-Surface Hardening on Formation of Hardened Structures in Steel 20GL

    Science.gov (United States)

    Evseev, D. G.; Savrukhin, A. V.; Neklyudov, A. N.

    2018-01-01

    Computer simulation of the kinetics of thermal processes and structural and phase transformations in the wall of a bogie side frame produced from steel 20GL is performed with allowance for the differences in the cooling intensity under volume-surface hardening. The simulation is based on the developed method employing the diagram of decomposition of austenite at different cooling rates. The data obtained are used to make conclusion on the effect of the cooling intensity on propagation of martensite structure over the wall section.

  13. Effect of Nonlinear Hardening of Lead Rubber Bearing on Long Term Behavior of Base Isolated Containment Building

    International Nuclear Information System (INIS)

    Park, Junhee; Choun, Young-Sun; Kim, Min-Kyu

    2015-01-01

    The rubber material used in laminated rubber bearings is the hyper elastic material whose stress-strain relationship can be defined as nonlinearly elastic. From the previous research, it was presented that the rubber hardness and stiffness was increased by the aging of LRB. The mechanical properties of LRB changed by aging can directly affect a nonlinear hardening behavior. Therefore it is needed to consider the nonlinear hardening effect for exactly evaluating the seismic safety of base isolated structure during the life time. In this study, the seismic response analysis of base isolated containment building was performed by using the bilinear model and the hardening model to identify the effect of structural response on the nonlinear hardening behavior of isolator. Moreover the floor response spectrum of base isolated structure considering the aging was analyzed by according to the analysis model of LRB.. The hardening behavior of lead rubber bearing occurs at high strain. Therefore it is reasonable to assume that the hysteretic model of LRB is the nonlinear hardening model for exactly evaluating the seismic response of base isolated structure. The nonlinear analysis of base isolated containment was performed by using the nonlinear hardening variables which was resulted from the test results and finite element analysis. From the analysis results, it was represented that the FRS was higher about 40% with nonlinear hardening model than with the bilinear model. Therefore the seismic response of base isolated structure with bilinear model can be underestimated than the real response. It is desired that the nonlinear hardening model of LRB is applied for the seismic risk evaluation requiring the ultimate state of LRB

  14. AISI/DOE Technology Roadmap Program: Development of Appropriate Resistance Spot Welding Practice for Transformation-Hardened Steels

    Energy Technology Data Exchange (ETDEWEB)

    Wayne Chuko; Jerry Gould

    2002-07-08

    This report describes work accomplished in the project, titled ''Development of Appropriate Resistance Spot Welding Practice for Transformation-Hardened Steels.'' The Phase 1 of the program involved development of in-situ temper diagrams for two gauges of representative dual-phase and martensitic grades of steels. The results showed that tempering is an effective way of reducing hold-time sensitivity (HTS) in hardenable high-strength sheet steels. In Phase 2, post-weld cooling rate techniques, incorporating tempering, were evaluated to reduce HTS for the same four steels. Three alternative methods, viz., post-heating, downsloping, and spike tempering, for HTS reduction were investigated. Downsloping was selected for detailed additional study, as it appeared to be the most promising of the cooling rate control methods. The downsloping maps for each of the candidate steels were used to locate the conditions necessary for the peak response. Three specific downslope conditions (at a fix ed final current for each material, timed for a zero-, medium-, and full-softening response) were chosen for further metallurgical and mechanical testing. Representative samples, were inspected metallographically, examining both local hardness variations and microstructures. The resulting downslope diagrams were found to consist largely of a C-curve. The softening observed in these curves, however, was not supported by subsequent metallography, which showed that all welds made, regardless of material and downslope condition, were essentially martensitic. CCT/TTT diagrams, generated based on microstructural modeling done at Oak Ridge National Laboratories, showed that minimum downslope times of 2 and 10 s for the martensitic and dual-phase grades of steels, respectively, were required to avoid martensite formation. These times, however, were beyond those examined in this study. These results show that downsloping is not an effective means of reducing HTS for

  15. Effect of chemical compositions and heat treatment on IGSCC resistance for strain hardened low carbon austenitic stainless steels in oxygenated water

    International Nuclear Information System (INIS)

    Yonezawa, T.; Kanasaki, H.; Fujimoto, K.; Taneike, M.; Ooki, S.; Sueishi, Y.; Tezuka, H.; Takamori, K.; Suzuki, S.

    2011-01-01

    In order to develop the highly resistant alternative materials to intergranular stress corrosion cracking (IGSCC) for the non-sensitized and strain hardened low carbon austenitic stainless steel in oxygenated water, the effects of chemical compositions and heat treatment conditions on the IGSCC resistance and stacking fault energy (SFE) values were studied for 33 laboratory melted steels and commercial type 310S stainless steel. The IGSCC resistance for test materials was compared by the maximum crack length, average crack length and cracked area in fatigue pre-cracked CT specimens after SCC test in oxygenated high temperature water. SFE values for these test materials were measured by the transmission electron microscopy on the width of isolated extended dislocations under g-3g weak beam condition for thin foils taken from the test materials, in this study. From these experiments, the effects of the chromium, molybdenum, nitrogen, silicon and manganese contents on the SCC resistance for non-aged materials were not so pronounced in this study. It is strongly suggested that the SFE value is a key parameter for the IGSCC resistance of the aged or non-aged and strain hardened low carbon austenitic stainless steels. (authors)

  16. Precursor composites for oxygen dispersion hardened silver sheathed superconductor composites

    Science.gov (United States)

    Podtburg, Eric R.

    1999-01-01

    An oxide superconductor composite having improved texture and durability. The oxide superconductor composite includes an oxide superconductor phase substantially surrounded with/by a noble metal matrix, the noble metal matrix comprising a metal oxide in an amount effective to form metal oxide domains that increase hardness of the composite. The composite is characterized by a degree of texture at least 10% greater than a comparable oxide superconductor composite lacking metal oxide domains. An oxide superconducting composite may be prepared by oxidizing the precursor composite under conditions effective to form solute metal oxide domains within the silver matrix and to form a precursor oxide in the precursor alloy phase; subjecting the oxidized composite to a softening anneal under conditions effective to relieve stress within the noble metal phase; and converting the oxide precursor into an oxide superconductor.

  17. Work hardening mechanism in high nitrogen austenitic steel studied by in situ neutron diffraction and in situ electron backscattering diffraction

    International Nuclear Information System (INIS)

    Ojima, M.; Adachi, Y.; Tomota, Y.; Ikeda, K.; Kamiyama, T.; Katada, Y.

    2009-01-01

    With a focus on microstructural hierarchy, work hardening behaviour in high nitrogen-bearing austenitic steel (HNS) was investigated mainly by a combined technique of in situ neutron diffraction and in situ electron backscattering diffraction (EBSD). Stress partitioning due to difference in deformability among grains is enhanced in HNS. The larger stress partitioning among [h k l]-oriented family grains seems to realize high work hardening at a small strain. At a larger strain, dislocation density is higher in HNS than in low nitrogen austenitic steel (LNS), which is a possible reason for high work hardening after straining proceeds, resulting in large uniform elongation.

  18. XRD investigation of microstructure strengthening mechanism of shot peening on laser hardened 17-4PH

    International Nuclear Information System (INIS)

    Wang Zhou; Luan Weizhi; Huang Junjie; Jiang Chuanhai

    2011-01-01

    Highlights: → We analyzed the microstructure of shot peened component. → We estimated the domain size, the microstrain and dislocation density of specimen via XRD profile method. → The domain size increased and microstrain as well as dislocation density decreased with depth increasing. → The surface domain size decreased to nano-scale after shot peening treatment. → The surface dislocation density increased about one order magnitude after shot peening treatment. - Abstract: The influence of shot peening on microstructure of laser hardened 17-4PH was investigated by using X-ray diffraction profiles. The domain size, microstrain and dislocation in different depths were calculated via Voigt method and dislocation density calculation method according to Williamson's work. Two typical materials in laser hardened 17-4PH (matrix material and laser hardened material) and three families of crystalline planes ({1 1 0}, {2 0 0}, {2 1 1}) were chosen as research objects. Microstructural results from XRD investigation quantified the shot peening influence on microstrain, domain size and dislocation density in microstructure changed layer in these three plane diffraction directions. Results showed that shot peening was an efficient cold working method to alter microstructure in near surface region and microstructure strengthening mechanism of shot peening played an important role on improving the surface mechanical properties. In microstructure changed layer, the domain size increased and microstrain as well as dislocation density decreased with depth increasing, which led to the mechanical properties decrease with depth increasing. With increasing peening intensity from 0.2 mmA + 0.1 mmA to 0.5 mmA + 0.1 mmA, the depth of microstructure changed layer increased but the surface microstructure did not change, no matter in matrix material or laser hardened material. As laser hardened material had a stronger resistance against shot peening influence on microstructure, the

  19. Nanotechnological applied tasks of the increase in the efficiency of the hardening processes of cement concrete

    Directory of Open Access Journals (Sweden)

    Chernishov Evgeny Mihalovich

    2017-02-01

    Full Text Available The scientific basis of the solution to the applied tasks of concrete technology through the use of «nano» tools, which provide the organization of the heterogeneous process of cement hydration and hardening, has been characterized. It is shown that the introduction of nanoadditives enables the direct regulation of the processes of structure formation in cement systems at the nanolevel. The effectiveness of the use of «nano» tools has been proposed to evaluate by means of complex criteria characterizing quantitatively the change in the activation energy, the rate of the process and time of its completion τ, the size and power consumption of the technology E while ensuring quality levels specified by R. According to the criteria, the monitoring of the results of the research has been made. Moreover, the most effective nanomodifying admixtures of two types have been identified. Type I is a compound nanoadditive based on nanoparticles SiO2 in combination with a superplasticizer, which mechanism of action is associated and also characterized by the increase in specific strength per unit measure the degree of cement hydration by 1.25–1.35 times. Engineering problems have been formulated. Moreover, the solutions are indicated for increasing the energy efficiency of the factory production of reinforced concrete products and structures. These solutions predetermine the reduction in the value of the maximum temperature for the curing of concrete, the reduction of the duration of the achievement of the required degree of cement hydration while concrete hardens, the reduction of time of cement concrete hardening to reach the regulated values of its strength, the increase in concrete strength per unit of cement consumption per m3 and energy efficiency of concrete hardening process in the preparation of reinforced concrete products. with the catalytic role in the processes of phase formation of nanoparticles of hydrated compounds. Type II is a

  20. HARDENING MONITORING AND CONTACT STRESS ANALYSIS OF TEST SAMPLES

    Directory of Open Access Journals (Sweden)

    Milan ŽMINDÁK

    2014-09-01

    Full Text Available The presented paper deals with the solution of rolling contact problem. A virtual model was created in Abaqus FEA software. The boundary conditions and contact forces were subsequently added. The results obtained after the simulation were compared with data obtained by experimental measurements, which were performed on the test stand ELSPO used in theoretical and technological center for plastometer construction materials for experimental analyzes and tests in terms of rolling contact of solids. The FEM simulation and experiment observed the size of the contact pressure, plastic deformation and the width of the track, which was the site of contact.

  1. THE EVALUATION OF TOOL WEAR IN THE MACHINING AISI 1050 STEEL HARDENED UP TO 53 HRC WITH COATED CARBIDE TOOL

    Directory of Open Access Journals (Sweden)

    Ali Rıza MOTORCU

    2006-03-01

    Full Text Available In this study, the machining of AISI 1050 steel which is hardened up to 53 HRC is carried out with two carbide tool materials (three layer coated carbide of TP100 containing Ti (C, N/Al2O3/TiN and (multi layer coated carbide of TP1000 containing Ti (C, N/Al2O3/ Ti (C, N/TiN. Cutting tests are performed with constant depth of cut and feed rate under dry cutting conditions. The flank wear is examined using an optical microscope. Tool life curves and Taylor Tool Life Equation constants (n, C are obtained via the flank wear data at various cutting speeds. The test results show that tools' performance is adversely affected by increasing cutting speed due to increased temperatures and stress generated at the cutting edges during machining. Flank wear and chipping/fracture of the tool edges are identified the major failure modes at the cutting conditions. TP1000 multilayer coated inserts give longer tool life than those of TP100 three layer coated inserts.

  2. Residual stresses in surface induction hardening of steels: Comparison between experiment and simulation

    International Nuclear Information System (INIS)

    Coupard, Dominique; Palin-luc, Thierry; Bristiel, Philippe; Ji, Vincent; Dumas, Christian

    2008-01-01

    Deep induction hardening has been performed on two batches of smooth cylindrical specimens with a hardening depth respectively around 2 mm and 3 mm. The distributions of axial and circumferential residual stresses are analysed for the two specimen batches by X-ray diffraction technique. The radial normal stress field is estimated through the use of the well known Moore and Evans correction. Finally, the experimental residual stresses are compared with those obtained from a multiphysic finite element modelling of the whole induction treatment process, including electromagnetic, thermal, metallurgical and mechanical phenomena. The simulated residual stress field is in good agreement with X-ray analysis especially at depths lower than one-tenth the specimen diameter. At deeper depths, a correction of the experimental X-ray analysis has been done to obtain realistic values

  3. Susceptibility and hardening of electronic systems to fast transient threats: new challenges ahead

    Science.gov (United States)

    Sabath, F.

    2004-05-01

    The field of susceptibility and hardening of electronic systems to transient threats has experienced a significant growth during the past ten years. Driven by the development in the area of non-lethal electromagnetic weapons it has become necessary to extend the classical set of transient threats, consisting of LEMP, ESD and NEMP, by a fast transient threat with an extreme bandwidth. The investigation of the susceptibility to those UWB threats, characterized by a bandwidth of more than a quarter of the center frequency, rise times of less than 200 ps and pulse durations in the ns regime, is of special interest. This paper presents an overview of current challenges of the hardening against UWB threats. It discusses recent research trends in transient susceptibility measurements, protection concepts and methods of analysis.

  4. Analysis and optimization of fault-tolerant embedded systems with hardened processors

    DEFF Research Database (Denmark)

    Izosimov, Viacheslav; Polian, Ilia; Pop, Paul

    2009-01-01

    In this paper we propose an approach to the design optimization of fault-tolerant hard real-time embedded systems, which combines hardware and software fault tolerance techniques. We trade-off between selective hardening in hardware and process reexecution in software to provide the required levels...... of fault tolerance against transient faults with the lowest-possible system costs. We propose a system failure probability (SFP) analysis that connects the hardening level with the maximum number of reexecutions in software. We present design optimization heuristics, to select the fault......-tolerant architecture and decide process mapping such that the system cost is minimized, deadlines are satisfied, and the reliability requirements are fulfilled....

  5. Barkhausen noise-magnetizing voltage sweep measurement in evaluation of residual stress in hardened components

    International Nuclear Information System (INIS)

    Santa-aho, Suvi; Vippola, Minnamari; Lepistö, Toivo; Sorsa, Aki; Leiviskä, Kauko; Hakanen, Merja

    2014-01-01

    In this study, Barkhausen noise (BN) magnetizing voltage sweep (MVS) measurement is used to evaluate non-destructively the surface residual stress state of hardened components. A new computational feature, where the maximum slope of the sweep is divided by the corresponding magnetizing voltage, is introduced. The results show that this feature has a linear relationship with the residual stress state of the samples. The determination of residual stresses during online production of components is a highly recognized task because tensile stresses may be detrimental to the component. In this study, two sets of hardened samples are used in the analysis. A linear relationship is observed in each sample set indicating that the new feature is applicable in assessment of surface residual stresses of the components. (paper)

  6. Radiation-hardened-by-design clocking circuits in 0.13-μm CMOS technology

    Science.gov (United States)

    You, Y.; Huang, D.; Chen, J.; Gong, D.; Liu, T.; Ye, J.

    2014-01-01

    We present a single-event-hardened phase-locked loop for frequency generation applications and a digital delay-locked loop for DDR2 memory interface applications. The PLL covers a 12.5 MHz to 500 MHz frequency range with an RMS Jitter (RJ) of 4.70-pS. The DLL operates at 267 MHz and has a phase resolution of 60-pS. Designed in 0.13-μm CMOS technology, the PLL and the DLL are hardened against SEE for charge injection of 250 fC. The PLL and the DLL consume 17 mW and 22 mW of power under a 1.5 V power supply, respectively.

  7. A general shakedown theorem for elastic/plastic bodies with work hardening

    International Nuclear Information System (INIS)

    Ponter, A.R.S.

    1975-01-01

    In recent years the design of metallic structures under variable loading has been assisted by the application of Melan's lower bound theorem for the shakedown on an elastic/perfectly plastic structure. The design codes for both portal frames and pressure vessels have taken account of such calculations. The theory of shakedown suffers from two defects, geometry changes are ignored and the material behaviour is described by a perfectly plastic constitutive relationship which includes neither work hardening nor the Bauschinger effect. This paper is concerned with the latter problem. A very general lower bound shakedown theorem is derived for an arbitrary time-independent material in terms of functional properties of the constitutive relationship. The theorem is then applied to perfect, isotropic and kinematic hardening plasticity. (Auth.)

  8. Study of the precipitation hardening process in recycled Al-Si-Cu cast alloys

    Directory of Open Access Journals (Sweden)

    Kuchariková L.

    2017-03-01

    Full Text Available The formation of extremely small uniformly dispersed particles of a second phase within the original phase matrix during heat treatment changed material properties. Therefore the characterization of precipitation had been investigated using high resolution transmission electron microscopy (TEM and electron diffraction of thin foils for an AlSi9Cu3 cast alloy. For investigation the hardening effect onto mechanical properties of aluminium cast was used heat treatment, which consisted from solution treatment at 515°C / 4 hours (h, followed by quenching into water with temperature 50°C and artificial aging using different temperatures 170°C and 190°C with different holding time 2, 4, 8, 16, and 32 hours. The observations of microstructure and substructure reveals that precipitation hardening has caused great changes in size, morphology and distributions of structural components, the formation of precipitates of Cu phases, and the change of mechanical properties as well.

  9. Development of production methods of volume source by the resinous solution which has hardening

    CERN Document Server

    Motoki, R

    2002-01-01

    Volume sources is used for standard sources by radioactive measurement using Ge semiconductor detector of environmental sample, e.g. water, soil and etc. that require large volume. The commercial volume source used in measurement of the water sample is made of agar-agar, and that used in measurement of the soil sample is made of alumina powder. When the plastic receptacles of this two kinds of volume sources were damaged, the leakage contents cause contamination. Moreover, if hermetically sealing performance of volume source made of agar-agar fell, volume decrease due to an evaporation off moisture gives an error to radioactive measurement. Therefore, we developed the two type methods using unsaturated polyester resin, vinilester resin, their hardening agent and acrylicresin. The first type is due to dispersing the hydrochloric acid solution included the radioisotopes uniformly in each resin and hardening the resin. The second is due to dispersing the alumina powder absorbed the radioisotopes in each resin an...

  10. The Studies of Irradiation Hardening of Stainless Steel Reactor Internals under Proton and Xenon Irradiation

    Directory of Open Access Journals (Sweden)

    Chaoliang Xu

    2016-06-01

    Full Text Available Specimens of stainless steel reactor internals were irradiated with 240 keV protons and 6 MeV Xe ions at room temperature. Nanoindentation constant stiffness measurement tests were carried out to study the hardness variations. An irradiation hardening effect was observed in proton- and Xe-irradiated specimens and more irradiation damage causes a larger hardness increment. The Nix-Gao model was used to extract the bulk-equivalent hardness of irradiation-damaged region and critical indentation depth. A different hardening level under H and Xe irradiation was obtained and the discrepancies of displacement damage rate and ion species may be the probable reasons. It was observed that the hardness of Xe-irradiated specimens saturate at about 2 displacement/atom (dpa, whereas in the case of proton irradiation, the saturation hardness may be more than 7 dpa. This discrepancy may be due to the different damage distributions.

  11. Susceptibility and hardening of electronic systems to fast transient threats: new challenges ahead

    Directory of Open Access Journals (Sweden)

    F. Sabath

    2004-01-01

    Full Text Available The field of susceptibility and hardening of electronic systems to transient threats has experienced a significant growth during the past ten years. Driven by the development in the area of non-lethal electromagnetic weapons it has become necessary to extend the classical set of transient threats, consisting of LEMP, ESD and NEMP, by a fast transient threat with an extreme bandwidth. The investigation of the susceptibility to those UWB threats, characterized by a bandwidth of more than a quarter of the center frequency, rise times of less than 200 ps and pulse durations in the ns regime, is of special interest. This paper presents an overview of current challenges of the hardening against UWB threats. It discusses recent research trends in transient susceptibility measurements, protection concepts and methods of analysis.

  12. Radiation- and temperature hardened components for in-vessel handling equipment

    International Nuclear Information System (INIS)

    Rohrbacher, H.A.; Rahn, A.; Suppan, A.; Decreton, M.; Moons, F.; Maisonnier, D.; Englert, M.

    1995-01-01

    During in-vessel remote operations on the NET/ITER fusion reactor, sensorics, motors and associated components being part of the handling equipment become exposed to a high gamma field of 30 Kilo-Gy/h (Si) at elevated ambient temperatures of 150 C. Component lifetimes of 300 hours for NET and 1000 hours for ITER are envisaged. Since such radiation- and temperature hardened components are not yet available on the market studies for the gamma-irradiation resistance of those components were indispensable with respect to functionality, lifetime and availability of the handling equipment, and have been launched at an early date. This contribution gives a review of the actual availability for gamma- and temperature hardened and appropriate driving and encoder systems. It reflects to the present achievements and shows up future activities for additional experiments performed on modified materials with view to a one decade higher gamma compatibility to fulfil the ITER in-pile environment requirements. (orig.)

  13. Prediction of beam hardening artefacts in computed tomography using Monte Carlo simulations

    DEFF Research Database (Denmark)

    Thomsen, M.; Bergbäck Knudsen, Erik; Willendrup, Peter Kjær

    2015-01-01

    We show how radiological images of both single and multi material samples can be simulated using the Monte Carlo simulation tool McXtrace and how these images can be used to make a three dimensional reconstruction. Good numerical agreement between the X-ray attenuation coefficient in experimental...... and simulated data can be obtained, which allows us to use simulated projections in the linearisation procedure for single material samples and in that way reduce beam hardening artefacts. The simulations can be used to predict beam hardening artefacts in multi material samples with complex geometry......, illustrated with an example. Linearisation requires knowledge about the X-ray transmission at varying sample thickness, but in some cases homogeneous calibration phantoms are hard to manufacture, which affects the accuracy of the calibration. Using simulated data overcomes the manufacturing problems...

  14. Specific Hardening Function Definition and Characterization of a Multimechanism Generalized Potential-based Viscoelastoplasticity Model

    Science.gov (United States)

    Arnold, S. M.; Saleeb, A. F.

    2003-01-01

    Given the previous complete-potential structure framework together with the notion of strain- and stress-partitioning in terms of separate contributions of several submechanisms (viscoelastic and viscoplastic) to the thermodynamic functions (stored energy and dissipation) a detailed viscoelastoplastic multimechanism characterization of a specific hardening functional form of the model is presented and discussed. TIMETAL 21S is the material of choice as a comprehensive test matrix, including creep, relaxation, constant strain-rate tension tests, etc. are available at various temperatures. Discussion of these correlations tests, together with comparisons to several other experimental results, are given to assess the performance and predictive capabilities of the present model particularly with regard to the notion of hardening saturation as well as the interaction of multiplicity of dissipative (reversible/irreversible) mechanisms.

  15. Unusual hardening behaviour in heavily cryo-rolled Cu-Al-Zn alloys during annealing treatment

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Y.L. [Faculty of Science, Kunming University of Science and Technology, Kunming 650500 (China); Ren, S.Y. [Ningbo Powerway Alloy Material Co., Ltd, Ningbo 315135 (China); Zeng, S.D. [Yunnan Institute of Measuring and Testing Technology, Kunming 650228 (China); Zhu, X.K., E-mail: xk_zhu@hotmail.com [Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650500 (China)

    2016-04-06

    Three nanostructured Cu-Al-Zn alloys were produced via rolling at the liquid nitrogen temperature. The deformed Cu alloys were then annealed at 150–300 °C for 1 h. The two alloys with high solute content and thus with low stacking fault energy exhibit unusual annealing hardening, namely, an increase in hardness and strength and a decrease in tensile elongation after annealing at 150 and 200 °C. From X-ray diffraction (XRD) analysis and microstructural observations by transmission electron microscopy (TEM), it is found that microstrain and dislocation density decrease after annealing at 200 °C because of the recovery of dislocations and the lattice parameter decreases due to solute segregation. Meanwhile, the twin density of the two Cu alloys increases and grain size remains basically unchanged. It is shown that the formation of annealing twins and stacking faults and the segregation of solute atoms may be the main causes of unusual annealing hardening.

  16. Surface hardening using cw CO2 laser: laser heat treatment, modelation, and experimental work

    Science.gov (United States)

    Muniz, German; Alum, Jorge

    1996-02-01

    In the present work are given the results of the application of laser metal surface hardening techniques using a cw carbon dioxide laser as an energy source on steel 65 G. The laser heat treatment results are presented theoretically and experimentally. Continuous wave carbon dioxide laser of 0.6, 0.3, and 0.4 kW were used. A physical model for the descriptions of the thermophysical laser metal interactions process is given and a numerical algorithm is used to solve this problem by means of the LHT code. The results are compared with the corresponding experimental ones and a very good agreement is observed. The LHT code is able to do predictions of transformation hardening by laser heating. These results will be completed with other ones concerning laser alloying and cladding presented in a second paper.

  17. Numerical model of phase transformation of steel C80U during hardening

    Directory of Open Access Journals (Sweden)

    T. Domański

    2007-12-01

    Full Text Available The article concerns numerical modelling of the phase transformations in solid state hardening of tool steel C80U. The transformations were assumed: initial structure – austenite, austenite – perlite, bainite and austenite – martensite. Model for evaluation of fractions of phases and their kinetics based on continuous heating diagram (CHT and continuous cooling diagram (CCT. The dilatometric tests on the simulator of thermal cycles were performed. The results of dilatometric tests were compared with the results of the test numerical simulations. In this way the derived models for evaluating phase content and kinetics of transformations in heating and cooling processes were verified. The results of numerical simulations confirm correctness of the algorithm that were worked out. In the numerical example the simulated estimation of the phase fraction in the hardened axisimmetrical element was performed.

  18. Determination of Coefficient of Convection Heat Transfer at Continual Induction Hardening of Axi-Symmetric Bodies

    Czech Academy of Sciences Publication Activity Database

    Barglik, J.; Doležel, Ivo; Ulrych, B.

    2003-01-01

    Roč. 928, č. 101 (2003), s. 9-16 ISSN 0374-4817 R&D Projects: GA ČR GA102/01/0184; GA MŠk ME 542 Grant - others:PSRC(PL) 4T08C 04823 Institutional research plan: CEZ:AV0Z2057903 Keywords : convective heat transfer coefficient * numerical modelling * induction hardening Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  19. Characterization of tool wear in high-speed milling of hardened powder metallurgical steels

    OpenAIRE

    Klocke, Fritz; Arntz, Kristian; Cabral, Gustavo Francisco; Stolorz, Martin; Busch, Marc

    2011-01-01

    In this experimental study, the cutting performance of ball-end mills in high-speed dry-hard milling of powder metallurgical steels was investigated. The cutting performance of the milling tools was mainly evaluated in terms of cutting length, tool wear, and cutting forces. Two different types of hardened steels were machined, the cold working steel HS 4-2-4 PM (K490 Microclean/66 HRC) and the high speed steel HS 6-5-3 PM (S790...

  20. SEU testing of a novel hardened register implemented using standard CMOS technology

    International Nuclear Information System (INIS)

    Monnier, T.; Roche, F.M.; Cosculluela, J.; Velazco, R.

    1999-01-01

    A novel memory structure, designed to tolerate SEU perturbations, has been implemented in registers and tested. The design was completed using a standard submicron nonradiation hardened CMOS technology. This paper presents the results of heavy ions tests which evidence the noticeable improvement of the SEU-robustness with an increased LET threshold and reduced cross-section, without significant impact to die real estate, write time, or power consumption

  1. IMPROVEMENT OF EQUIPMENT FOR EFFECTIVE HARDENING SAND MIXTURE BY VACUUM MOLDING

    Directory of Open Access Journals (Sweden)

    V. S. Doroshenko

    2016-01-01

    Full Text Available The review deals with the design flask tooling and patterns for effective hardening sand mixture in the vacuum molding (V-Process, and molding on a one-off patterns (Lost Foam Casting. Sealing and evacuating sand mixture – two major factors influence the strength of the casting mold and casting quality, management practices which will enable to improve the casting process.

  2. Radiation Effects and Component Hardening testing program at the Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    Draper, J.V.; Weil, B.S.; Chesser, J.B.

    1993-01-01

    This paper describes Phase II of the Radiation Effects and Component Hardening (REACH) testing program, performed as part of the joint collaborative agreement between the United States Department of Energy (USDOE) and the Power Reactor and Nuclear Fuel Development Corporation (PNC) of Japan, Components and materials were submitted to 10 5 R/hr gamma radiation fields for 10,000 hr, producing accumulated doses of 10 9 R; most performed as expected

  3. Principles and techniques of radiation hardening. Volume 2. Transient radiation effects in electronics (TREE)

    International Nuclear Information System (INIS)

    Rudie, N.J.

    1976-01-01

    The three-volume book is intended to serve as a review of the effects of thermonuclear explosion induced radiation (x-rays, gamma rays, and beta particles) and the resulting electromagnetic pulse (EMP). Volume 2 deals with the following topics: radiation effects on quartz crystals, tantalum capacitors, bipolar semiconductor devices and integrated circuits, field effect transistors, and miscellaneous electronic devices; hardening electronic systems to photon and neutron radiation; nuclear radiation source and/or effects simulation techniques; and radiation dosimetry

  4. Reproduction studies in the rat with shea oleine and hardened shea oleine.

    Science.gov (United States)

    Baldrick, P; Robinson, J A; Hepburn, P A

    2001-09-01

    Shea oleine is an oil fraction derived from the nut of the tree Butyrospermum parkii, which grows in central and western Africa. There are several uses of shea oleine including its use as a frying oil and, after hardening, in margarine and toffee fat. This investigation was performed to examine the toxicity of 7 or 15% hardened shea oleine in comparison with 7 or 15% unhardened shea oleine and various commercially available materials, sheanut and palm oils, cocoa butter and toffee powder following dietary administration to rats during pre-mating, mating, pregnancy and offspring weaning in two separate investigations. Reproduction was assessed using number of litters and pups born plus survival and body weights at birth and at weaning on day 21. Skeletal evaluation using X-ray, clinical pathology and a macroscopic examination were also performed for F1 rats. Study measures for parent animals comprised evaluation of body weight, food consumption, clinical pathology, organ weights and macroscopic examination. Fatty acids and hydrocarbon levels were measured and an evaluation for lipogranulomata was made for various tissues. Results showed that shea oleine, whether unhardened or hardened, produced no evidence of reproduction toxicity and gave a similar profile to the other commercially available materials used in this study in the rat. Minor findings with shea oleine were not related to reproduction performance but comprised slightly reduced body weight gain and reduced cholesterol and raised alkaline phosphatase levels. None of the findings in this study were considered to be of toxicological significance. Thus, no evidence of reproduction toxicity was seen for both unhardened and hardened shea oleine in this investigation in the rat at levels equating to greater than 7.5 g/kg/day.

  5. Strain hardening in startup shear of long-chain branched polymer solutions.

    Science.gov (United States)

    Liu, Gengxin; Cheng, Shiwang; Lee, Hyojoon; Ma, Hongwei; Xu, Hongde; Chang, Taihyun; Quirk, Roderic P; Wang, Shi-Qing

    2013-08-09

    We show for the first time that entangled polymeric liquids containing long-chain branching can exhibit strain hardening upon startup shear. As the significant long-chain branching impedes chain disentanglement, Gaussian coils between entanglements can deform to reach the finite extensibility limit where the intrachain retraction force exceeds the value expected from the usual conformational entropy loss evaluated based on Gaussian chain statistics. The phenomenon is expected to lead to further theoretical understanding.

  6. Radiation hardening and irradiation testing of in-cell electronics for MA23/APM

    International Nuclear Information System (INIS)

    Friant, A.

    1988-09-01

    We relate briefly the radiation hardening method used to guarantee a gamma resistance of 10 Mrad for the whole electronic equipment associated with the slave arm of MA23 M servomanipulator which will be set up in cell 404 in Marcoule (APM). We describe the radiation testing of electronic devices and of the various subsystems designed by the D. LETI groups involved in the MA23/APM project

  7. Lattice plane spacing change in hardened layer of chrome molybdenum steel after carburizing and quenching

    International Nuclear Information System (INIS)

    Sakaida, Yoshihisa; Kawauchi, Motonori; Shobu, Takahisa

    2011-01-01

    Block specimens of chrome molybdenum steel with 0.20 mass% C, SCM420, were carburized in carrier gas and quenched in oil bath. The hardness and carbon content gradients in the hardened layer were measured experimentally. The carburized surface of one block specimen was gradually removed by electrolytic polishing. Ten thin plates were cut from the total case depth of the other block specimen. An experimental method to determine the stress-free lattice plane spacing of the hardened layer was examined using x-ray and neutron radiations. As a result, the stress-free lattice plane spacing change in the hardened layer could be determined successfully by measuring neutron diffraction peaks from Fe-211 of the thin plates during rotating ±90deg around the specimen axis. Using x-ray, the stress-free lattice plane spacing at the carburized surface could be also determined by measuring the 2θ-sin 2 ψ diagrams of either removed surface of block specimen or thin plate. However, under the carburized surface, the K α2 diffraction from the heat-treated eutectoid phase was superimposed on x-ray diffraction peak because the subsurface microstructure was composed of martensitic and heat-treated eutectoid phases. The stress-free lattice plane spacing under the carburized surface could not be determined using x-ray. Furthermore, the stress-free lattice plane spacing of Fe-211 was found to decrease with increasing the distance from the carburized surface and be expressed by the cubic function of the carbon content in the hardened layer. (author)

  8. Action of age-hardening on the copper single crystals after ion implantation

    International Nuclear Information System (INIS)

    Kul'ment'eva, O.P.; Kul'ment'ev, A.I.

    2007-01-01

    High-dose implantation (up to (1-5)·10 17 cm -2 ) of tantalum ions into a copper single crystal of (100), (110) and (111) orientation has been investigated. Modified properties just after ion implantation and subsequent age-hardening during ten years were studied. It was shown that ion implantation and subsequent masstransfer process results in sufficient long-term stable changes of the microhardness. (authors)

  9. The Studies of Irradiation Hardening of Stainless Steel Reactor Internals under Proton and Xenon Irradiation

    OpenAIRE

    Xu, Chaoliang; Zhang, Lu; Qian, Wangjie; Mei, Jinna; Liu, Xiangbing

    2016-01-01

    Specimens of stainless steel reactor internals were irradiated with 240 keV protons and 6 MeV Xe ions at room temperature. Nanoindentation constant stiffness measurement tests were carried out to study the hardness variations. An irradiation hardening effect was observed in proton- and Xe-irradiated specimens and more irradiation damage causes a larger hardness increment. The Nix-Gao model was used to extract the bulk-equivalent hardness of irradiation-damaged region and critical indentation ...

  10. Surface hardening of 30CrMnSiA steel using continuous electron beam

    Science.gov (United States)

    Fu, Yulei; Hu, Jing; Shen, Xianfeng; Wang, Yingying; Zhao, Wansheng

    2017-11-01

    30CrMnSiA high strength low alloy (HSLA) carbon structural steel is typically applied in equipment manufacturing and aerospace industries. In this work, the effects of continuous electron beam treatment on the surface hardening and microstructure modifications of 30CrMnSiA are investigated experimentally via a multi-purpose electron beam machine Pro-beam system. Micro hardness value in the electron beam treated area shows a double to triple increase, from 208 HV0.2 on the base metal to 520 HV0.2 on the irradiated area, while the surface roughness is relatively unchanged. Surface hardening parameters and mechanisms are clarified by investigation of the microstructural modification and the phase transformation both pre and post irradiation. The base metal is composed of ferrite and troostite. After continuous electron beam irradiation, the micro structure of the electron beam hardened area is composed of acicular lower bainite, feathered upper bainite and part of lath martensite. The optimal input energy density for 30CrMnSiA steel in this study is of 2.5 kJ/cm2 to attain the proper hardened depth and peak hardness without the surface quality deterioration. When the input irradiation energy exceeds 2.5 kJ/cm2 the convective mixing of the melted zone will become dominant. In the area with convective mixing, the cooling rate is relatively lower, thus the micro hardness is lower. The surface quality will deteriorate. Chemical composition and surface roughness pre and post electron beam treatment are also compared. The technology discussed give a picture of the potential of electron beam surface treatment for improving service life and reliability of the 30CrMnSiA steel.

  11. STUDY OF THE HARDENING TEMPERATURE INFLUENCE ON PROCESSES WHEN TEMPERING CARBON STEEL

    Directory of Open Access Journals (Sweden)

    Ms. Irina L. Polyanskaya

    2016-12-01

    Full Text Available The article presents the research results of carbon steel electrical resistance changes at low tem-pering and determines the effect of temperature on the electrical resistance. The analysis of the results showed that the influence of carbon on the value of the electrical resistance is higher than the influence of the crystal structure defects. The changes of the hardened steel electrical resistance are due to the redistri-bution of carbon.

  12. On the rate of black hole binary mergers in galactic nuclei due to dynamical hardening

    Science.gov (United States)

    Leigh, N. W. C.; Geller, A. M.; McKernan, B.; Ford, K. E. S.; Mac Low, M.-M.; Bellovary, J.; Haiman, Z.; Lyra, W.; Samsing, J.; O'Dowd, M.; Kocsis, B.; Endlich, S.

    2018-03-01

    We assess the contribution of dynamical hardening by direct three-body scattering interactions to the rate of stellar-mass black hole binary (BHB) mergers in galactic nuclei. We derive an analytic model for the single-binary encounter rate in a nucleus with spherical and disc components hosting a super-massive black hole (SMBH). We determine the total number of encounters NGW needed to harden a BHB to the point that inspiral due to gravitational wave emission occurs before the next three-body scattering event. This is done independently for both the spherical and disc components. Using a Monte Carlo approach, we refine our calculations for NGW to include gravitational wave emission between scattering events. For astrophysically plausible models, we find that typically NGW ≲ 10. We find two separate regimes for the efficient dynamical hardening of BHBs: (1) spherical star clusters with high central densities, low-velocity dispersions, and no significant Keplerian component and (2) migration traps in discs around SMBHs lacking any significant spherical stellar component in the vicinity of the migration trap, which is expected due to effective orbital inclination reduction of any spherical population by the disc. We also find a weak correlation between the ratio of the second-order velocity moment to velocity dispersion in galactic nuclei and the rate of BHB mergers, where this ratio is a proxy for the ratio between the rotation- and dispersion-supported components. Because discs enforce planar interactions that are efficient in hardening BHBs, particularly in migration traps, they have high merger rates that can contribute significantly to the rate of BHB mergers detected by the advanced Laser Interferometer Gravitational-Wave Observatory.

  13. Numerical convergence in simulations of multiaxial ratcheting with directional distortional hardening

    Czech Academy of Sciences Publication Activity Database

    Welling, CH.A.; Marek, René; Feigenbaum, H. P.; Dafalias, Y.F.; Plešek, Jiří; Hrubý, Zbyněk; Parma, Slavomír

    2017-01-01

    Roč. 126, November (2017), s. 105-121 ISSN 0020-7683 R&D Projects: GA MŠk(CZ) EF15_003/0000493; GA MŠk LH14018 Keywords : plasticity * yield * ratcheting * yield surface distortion * directional distortional hardening Subject RIV: JG - Metallurgy OBOR OECD: Materials engineering Impact factor: 2.760, year: 2016 http://www.sciencedirect.com/science/article/pii/S0020768317303499

  14. Epoxy adhesive formulations for engineered wood manufacturing: Design of Experiment (DOE) and hardener modification

    Science.gov (United States)

    Wangkheeree, W.; Meekum, U.

    2016-03-01

    The effect of IPDA, DDS, BPA and DICY, as main ingredient of TETA based hardener were examined. The 2k design of experiment(DOE) with k=3 were preliminary explored. The designed parameters A(IPDA), B(DDS) and C(BPA) were assigned as low(-) and high(+) levels, respectively. The Design Expert™ was hired as the analyzing tool at α=0.05. The mixed epoxy resin was based on the commercial one. The designed responds including tcure, t50, impact strengths, flexural properties and HDT were measured, respectively. Regarding to ANOVA conclusion, it was found that, there were no significant effects on the assigned parameters on the interested responds, except for the HDT where BPA(C) was negative effect was found. The lower in the crosslink density of cured epoxy, inferior in HDT, the higher in BPA addition was hypothesized. It was found that impact strength of cured epoxy derived from all formula were unacceptable low and tcure and t50, were too short. Thus, the further investigation by adding DICY into hardener was explored. The results showed that no significant change by mechanical means of cured epoxy by resolving 5-30 phr of DICY into the hardener. However, it was observed that the DICY added formula showed the obvious long cure times and behave as prepreg formula. The room temperature cured epoxy was incompletely crosslinked. The degrees of linear chain fragment were evidence, by weight, when higher DICY loading was engaged. Complete crosslink was achieved at 150°C post curing. The hardener comprised of TETA/aliphatic Epoxy(RD108) adduct was studied for enhancing the toughness of epoxy resin. It was observed that longer cure time at 150°C but lower toughness was experienced, on both prepreg and engineered wood made from the resins, at high TETA/RD108 ratio. Incomplete cure was explained for the mechanical inferior at high RD108 loading.

  15. The swelling, microstructure, and hardening of wrought LCAC, TZM, and ODS molybdenum following neutron irradiation

    Science.gov (United States)

    Cockeram, B. V.; Smith, R. W.; Hashimoto, N.; Snead, L. L.

    2011-11-01

    TEM examinations and swelling measurements were performed on commercially available wrought Low Carbon Arc Cast (LCAC), La-oxide Oxide Dispersion Strengthened (ODS), and TZM molybdenum alloys following irradiation in the High Flux Isotope Reactor (HFIR) at 300 °C, 600 °C, and 900 °C to neutron fluences between 1.05 and 24.7 × 10 25 n/m 2 ( E > 0.1 MeV), or 0.6-13.1 dpa. The defect structure, hardening, and swelling were shown to be strongly dependent on irradiation temperature and starting microstructure. Irradiation at 300 °C results in the formation of a high number density of fine loops and voids (˜1 nm) that produce significant hardening and low swelling that is comparable for all alloys. Irradiation at 600 °C-784 °C produces a high number density of larger voids (5-6 nm) that results in significant hardening with the highest swelling. A low number density of the largest void sizes (8-30 nm) are formed for the 900 °C irradiation that result in low hardening and less swelling than observed for the 600 °C irradiation. The fine grain size of ODS Mo results in a higher concentration of denuded zones along grain boundaries and improved ductile-laminate toughening that results in improved resistance to irradiation embrittlement for the 600 °C irradiations. Irradiation-induced formation of precipitates rich in transmutation products is observed at the highest dose, and it is likely that these features exert an influence on subsequent void growth.

  16. X-Ray diffraction study of strain hardening and annealing in an UNS S31803 duplex stainless steel; Estudo por difracao de raios-X do encruamento e do recozimento do aco inoxidavel duplex UNS S318031

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, Denilson Jose Marcolino de; Padilha, Angelo Fernando [Universidade de Sao Paulo (EP/USP), Sao Paulo, SP (Brazil). Departamento de Engenharia Metalurgica e de Materiais; Lima, Nelson Batista de [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2010-07-01

    In the present work the phenomena of strain hardening, formation and reversion of the strain induced alpha-prime martensite (α', CCC, Ferromagnetic) in an UNS S31803 duplex stainless steel have been studied. Initially, the microstructure of the material in the solution annealed condition was characterized with aid of several complementary techniques of microstructural analysis. The volumetric fraction, crystalline structure, chemical composition, size and morphology of the two phases (ferrite and austenite) have been determined. The phenomena of strain hardening, formation and reversion of strain induced martensite in the austenite phase and recovery of austenite and ferrite phases have been studied, predominantly by using X-ray diffraction and the Rietveld method. (author)

  17. The Numerical Analysis of the Phenomena of Superficial Hardening of the Hot-Work Tool Steel Elements / Analiza Numeryczna Zjawisk Przypowierzchniowego Hartowania Elementów Ze Stali Narzędziowej Do Pracy Na Gorąco

    Directory of Open Access Journals (Sweden)

    Bokota A.

    2015-12-01

    Full Text Available In the paper the complex model of hardening of the hot-work tool steel is presented. Model of estimation of phase fractions and their kinetics is based on the continuous heating diagram (CHT and cooling diagram (CCT. Phase fractions which occur during the continuous heating and cooling (austenite, pearlite or bainite are described by Johnson-Mehl (JM formula. To determine of the formed martensite the modified Koistinen-Marburger (KM equation is used. Model takes into account the thermal, structural, plastic strains and transformation plasticity. To calculate the plastic strains the Huber-Mises plasticity condition with isotopic hardening is used. Whereas to determine transformations induced plasticity the Leblond model is applied. The numerical analysis of phase compositions and residual stresses in the hot-work steel (W360 element is considered.

  18. A Compact, Radiation Hardened, Stable, Low Power, Programmable Crystal Oscillator for Extreme Temperature and High Reliability Space Application Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose a feasibility study of a fully intgrated radiation hardened (>1Mrad/si), programmable crystal oscilator (RPXO) in a miniature package that will deliver...

  19. Effect of the hardener to epoxy monomer ratio on the water absorption behavior of the DGEBA/TETA epoxy system

    Directory of Open Access Journals (Sweden)

    Ayrton Alef Castanheira Pereira

    2016-02-01

    Full Text Available Abstract The water absorption behavior of the DGEBA/TETA epoxy system was evaluated as a function of the epoxy monomer to amine hardener ratio. Weight gain versus immersion time curves were obtained and the experimental points were fitted using Fickian and Non-Fickian diffusion models. The results obtained showed that for all epoxy monomer to hardener ratios analyzed water diffusion followed non-Fickian behavior. It was possible to correlate the water absorption behavior to the macromolecular structure developed when the epoxy/ hardener ratio was varied. All epoxy/hardener ratios present a two-phase macromolecular structure, composed of regions with high crosslink density and regions with lower crosslinking. Epoxy rich systems have a more open macromolecular structure with a lower fraction of the dense phase than the amine rich systems, which present a more compact two-phase structure.

  20. Process-Hardened, Multi-Analyte Sensor for Characterizing Rocket Plum Constituents Under Test Environment, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This STTR project aims to develop a process-hardened, simple and low cost multi-analyte sensor for detecting components of rocket engine plumes. The sensor will be...