Heat treatment effect on the microstructure, tensile properties and dry sliding wear behavior of A356-10%B4C cast composites

International Nuclear Information System (INIS)

Lashgari, H.R.; Zangeneh, Sh.; Shahmir, H.; Saghafi, M.; Emamy, M.

2010-01-01

In present paper, an attempt was made to examine the influence of T6 heat treatment (solution treatment at 540 o C for 5 h, quenching in hot water and artificial aging at 170 o C for 8 h) on the microstructure, tensile properties and dry sliding wear behavior of A356-10%B 4 C cast composites. The composite ingots were made by stir casting process. In this work, the matrix alloy and composite were characterized by optical microscope, scanning electron microscope equipped with energy dispersive X-ray spectroscopy, tensile tests and conventional pin-on-disk experiment. The obtained results showed that in Al-B 4 C composite, T6 treatment was a dominant factor on the hardness improvement in comparison with hardness increasing due to the addition of B 4 C hard particles. In addition, T6 treatment can contribute to the strong bonding between B 4 C and matrix alloy and also it can change eutectic silicon morphology from acicular to near spherical. This case can lead to higher strength and wear properties of heat treated metal matrix composites in comparison with unheat treated state. Observation of worn surfaces indicated detachment of mechanically mixed layer which can primarily due to the delamination wear mechanism under higher applied load.

Effect of composition and heat treatment on the phase formation of mechanically alloyed Cr-B and Mo-B powders

International Nuclear Information System (INIS)

Wu, H M; Hu, C J; Pai, K Y

2009-01-01

Blended elemental Cr-B and Mo-B powders in atomic ratio of 67:33, 50:50, and 20:80 were subjected to mechanical alloying up to 60 h and subsequent heat treatment to investigate effect of composition and heat treatment on the phase formation of Cr-B and Mo-B powders. It was studied by X-ray diffraction and differential thermal analysis. Mechanical alloying these powder mixtures for 60 h leads essentially to a amorphous structure except for the Mo 20 B 80 powder, which creates a partially amorphous MoB 4 structure. Annealing at lower temperatures relieves the strains cumulative in the milled powders and creates no new phase. The structures obtained after annealing the milled powders at higher temperature vary and depend on the overall composition of the powder mixtures. Annealing the milled Mo-B powders having greater Mo content ends up with a dissociation reaction at higher temperature.

Effects of heat treatment on optical absorption properties of Ni-P/AAO nano-array composite structure

Energy Technology Data Exchange (ETDEWEB)

Liu, Yi-Fan; Wang, Feng-Hua; Guo, Dong-Lai; Huang, Sheng-You; Zou, Xian-Wu [Wuhan University, Department of Physics, Wuhan (China); Sang, Jian-Ping [Wuhan University, Department of Physics, Wuhan (China); Jianghan University, Department of Physics, Wuhan (China)

2009-11-15

Ni-P/AAO nano-array composite structure assemblies with Ni and P grown in the pores of anodic aluminum oxide (AAO) membranes were prepared by electroless deposition. The results of SEM, TEM and SAED show that as-deposited Ni-P nanowires have an amorphous structure and a few nanocrystallites form after annealing. The optical absorption spectra reveal that, as the annealing temperature increases, the absorption band edge of the Ni-P/AAO composite structure is obviously blue shifted, which is attributed to a decrease of the internal pressure after heat treatment. Meanwhile, the annealed Ni-P/AAO nano-array composite structure exhibits the absorption behavior of a direct band gap semiconductor. Details of this behavior are discussed together with the implications for potential device applications. (orig.)

Wide-angle X-ray scattering study of heat-treated PEEK and PEEK composite

Science.gov (United States)

Cebe, Peggy; Lowry, Lynn; Chung, Shirley Y.; Yavrouian, Andre; Gupta, Amitava

1987-01-01

Samples of poly(etheretherketone) (PEEK) neat resin and APC-2 carbon fiber composite were subjected to various heat treatments, and the effect of quenching and annealing treatments was studied by wide-angle X-ray scattering. It is found that high-temperature treatments may introduce disorder into neat resin and composite PEEK when followed by rapid cooling. The disorder is metastable and can revert to ordered state when the material is heated above its glass transition temperature and then cooled slowly. The disorder may result from residual thermal stresses.

Effects of post-heat treatment on microstructure and properties of laser cladded composite coatings on titanium alloy substrate

Science.gov (United States)

Li, G. J.; Li, J.; Luo, X.

2015-01-01

The composite coatings were produced on the Ti6Al4V alloy substrate by laser cladding. Subsequently, the coatings were heated at 500 °C for 1 h and 2 h and then cooled in air. Effects of post-heat treatment on microstructure, microhardness and fracture toughness of the coatings were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), optical microscopy (OM). Wear resistance of the coatings was evaluated under the dry sliding reciprocating friction condition at room temperature. The results indicated that the coatings mainly consist of a certain amount of coarse white equiaxed WC particles surrounded by the white-bright W2C, a great deal of fine dark spherical TiC particles and the matrix composed of the α(Ti), Ti2Ni and TiNi phases. Effects of the post-heat treatment on phase constituents and microstructure of the coatings were almost negligible due to the low temperature. However, the post-heat treatment could decrease the residual stress and increase fracture toughness of the coatings, and fracture toughness of the coatings was improved from 2.77 MPa m1/2 to 3.80 MPa m1/2 and 4.43 MPa m1/2 with the heat treatment for 1 h and 2 h, respectively. The mutual role would contribute to the reduction in cracking susceptibility. Accompanied with the increase in fracture toughness, microhardness of the coatings was reduced slightly. The dominant wear mechanism for all the coatings was abrasive wear, characterized by micro-cutting or micro-plowing. The heat treatment could significantly decrease the average friction coefficient and reduce the fluctuation of the friction coefficient with the change in sliding time. The appropriate heat treatment time (approximately 1 h) had a minimal effect on wear mass loss and volume loss. Moreover, the improvement in fracture toughness will also be beneficial to wear resistance of the coatings under the long service.

Influence of heat treatment on hardness and kinetics of growth of intermetallic compound interlayer in titanium-steel composite material

International Nuclear Information System (INIS)

Shmorgun, V.G.; Slaustin, O.V.; Trykov, Yu.P.

2005-01-01

The effect of heat treatment conditions on microhardness and diffusion interlayer thickness is studied for composite material of titanium VT1-O + steel 08kp + titanium VT1-O. Heat treatments are carried out at temperatures of 800-1000 deg C and holding at heat for 3 h in a vacuum furnace (1 x 10 -4 mmHg) as well as in an electric furnace with coating a dual protective layer. It is stated that the hardness and the thickness of the interlayer are higher after heat treatment in an ordinary electric furnaces as compared to vacuum heating. all other things being equal. Annealed in electric furnace specimens are water quenched from temperatures of 600-950 deg C. It is shown that the hardness of the interlayer increases sharply when hardening from 650 deg C comparing with annealed specimens (from 4.5-5.2 to 7-9 GPa). The quenching from 700 and 800 deg C results in an interlayer hardness decrease down to 4.8-5.4 and 3.1-3 GPa respectively. A quenching temperature increase up to 800-900 deg C is accompanied by a monotonic enhancement of hardness from 3.5-4.8 up to 5.1-6.8 GPa [ru

Phase composition of Al-Ti-Nb-Mo γ alloys in the heat-treatment temperature range: Calculation and experiment

Science.gov (United States)

Belov, N. A.; Dashkevich, N. I.; Bel'tyukova, S. O.

2015-07-01

The phase composition of TNM-type Al-Ti-Nb-Mo γ alloys at heat-treatment temperatures is quantitatively studied using the Thermo-Calc program package and experimental methods. Isothermal cross sections are calculated and the joint influence of two alloying elements on the phase composition of the alloy is determined at the mean concentration of a third component. Based on the calculations of vertical cross sections, the boundaries of the four-phase eutectoid reaction α → α2 + β + γ are found. The temperature is shown to significantly influence the phase compositions of the γ alloys, among them the mass fractions of various phases (α, β, γ,α2) and the element concentration in them.

Cold spraying SiC/Al metal matrix composites: effects of SiC contents and heat treatment on microstructure, thermophysical and flexural properties

Science.gov (United States)

Gyansah, L.; Tariq, N. H.; Tang, J. R.; Qiu, X.; Feng, B.; Huang, J.; Du, H.; Wang, J. Q.; Xiong, T. Y.

2018-02-01

In this paper, cold spray was used as an additive manufacturing method to fabricate 5 mm thick SiC/Al metal matrix composites with various SiC contents. The effects of SiC contents and heat treatment on the microstructure, thermophysical and flexural properties were investigated. Additionally, the composites were characterized for retention of SiC particulates, splat size, surface roughness and the progressive understanding of strengthening, toughening and cracking mechanisms. Mechanical properties were investigated via three-point bending test, thermophysical analysis, and hardness test. In the as-sprayed state, flexural strength increased from 95.3 MPa to 133.5 MPa, an appreciation of 40% as the SiC contents increased, and the main toughening and strengthening mechanisms were zigzag crack propagation and high retention of SiC particulates respectively. In the heat treatment conditions, flexural strength appreciated significantly compared to the as-sprayed condition and this was as a result of coarsening of pure Al splat. Crack branching, crack deflection and interface delamination were considered as the main toughening mechanisms at the heat treatment conditions. Experimental results were consistent with the measured CTE, hardness, porosity and flexural modulus.

Effect of Heat Treatment on the Microstructure and Wear Properties of Al-Zn-Mg-Cu/In-Situ Al-9Si-SiCp/Pure Al Composite by Powder Metallurgy

Science.gov (United States)

Yu, Byung Chul; Bae, Ki-Chang; Jung, Je Ki; Kim, Yong-Hwan; Park, Yong Ho

2018-03-01

This study examined the effects of heat treatment on the microstructure and wear properties of Al-Zn-Mg-Cu/in-situ Al-9Si-SiCp/pure Al composites. Pure Al powder was used to increase densification but it resulted in heterogeneous precipitation as well as differences in hardness among the grains. Heat treatment was conducted to solve this problem. The heat treatment process consisted of three stages: solution treatment, quenching, and aging treatment. After the solution treatment, the main dissolved phases were η'(Mg4Zn7), η(MgZn2), and Al2Cu phase. An aging treatment was conducted over the temperature range, 100-240 °C, for various times. The GP zone and η'(Mg4Zn7) phase precipitated at a low aging temperature of 100-160 °C, whereas the η(MgZn2) phase precipitated at a high aging temperature of 200-240 °C. The hardness of the sample aged at 100-160 °C was higher than that aged at 200-240 °C. The wear test was conducted under various linear speeds with a load of 100 N. The aged composite showed a lower wear rate than that of the as-sintered composite under all conditions. As the linear speed was increased to 1.0 m/s, the predominant wear behavior changed from abrasive to adhesive wear in all composites.

Effect of Heat Treatment on the Microstructure and Wear Properties of Al-Zn-Mg-Cu/In-Situ Al-9Si-SiCp/Pure Al Composite by Powder Metallurgy

Science.gov (United States)

Yu, Byung Chul; Bae, Ki-Chang; Jung, Je Ki; Kim, Yong-Hwan; Park, Yong Ho

2018-05-01

This study examined the effects of heat treatment on the microstructure and wear properties of Al-Zn-Mg-Cu/in-situ Al-9Si-SiCp/pure Al composites. Pure Al powder was used to increase densification but it resulted in heterogeneous precipitation as well as differences in hardness among the grains. Heat treatment was conducted to solve this problem. The heat treatment process consisted of three stages: solution treatment, quenching, and aging treatment. After the solution treatment, the main dissolved phases were η'(Mg4Zn7), η(MgZn2), and Al2Cu phase. An aging treatment was conducted over the temperature range, 100-240 °C, for various times. The GP zone and η'(Mg4Zn7) phase precipitated at a low aging temperature of 100-160 °C, whereas the η(MgZn2) phase precipitated at a high aging temperature of 200-240 °C. The hardness of the sample aged at 100-160 °C was higher than that aged at 200-240 °C. The wear test was conducted under various linear speeds with a load of 100 N. The aged composite showed a lower wear rate than that of the as-sintered composite under all conditions. As the linear speed was increased to 1.0 m/s, the predominant wear behavior changed from abrasive to adhesive wear in all composites.

Water Absorption Properties of Heat-Treated Bamboo Fiber and High Density Polyethylene Composites

Directory of Open Access Journals (Sweden)

Lanxing Du

2014-01-01

Full Text Available To modify water absorption properties of bamboo fiber (BF and high density polyethylene (HDPE composites, heat treatment of BFs was performed prior to compounding them with HDPE to form the composites. The moisture sorption property of the composites was measured and their diffusion coefficients (Dm were evaluated using a one-dimensional diffusion model. Moisture diffusion coefficient values of all composites were in the range of 0.115x10-8 to 1.267x10-8 cm2/s. The values of Dm decreased with increasing BF heat-treatment temperature, and increased with increasing BF loading level. The Dm value of 40 wt% bamboo fiber/HDPE composites with BFs treated with 100 oC was the greatest (i.e., 1.267x10-8cm2/s. Morphology analysis showed increased fiber-matrix interfacial bonding damage due to fiber swelling and shrinking from water uptaking and drying. The mechanism of water absorption of the composite, indicated a general Fickian diffusion process.

Pre-heating mitigates composite degradation.

Science.gov (United States)

Silva, Jessika Calixto da; Rogério Vieira, Reges; Rege, Inara Carneiro Costa; Cruz, Carlos Alberto dos Santos; Vaz, Luís Geraldo; Estrela, Carlos; Castro, Fabrício Luscino Alves de

2015-01-01

Dental composites cured at high temperatures show improved properties and higher degrees of conversion; however, there is no information available about the effect of pre-heating on material degradation. Objectives This study evaluated the effect of pre-heating on the degradation of composites, based on the analysis of radiopacity and silver penetration using scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS). Material and Methods Thirty specimens were fabricated using a metallic matrix (2x8 mm) and the composites Durafill VS (Heraeus Kulzer), Z-250 (3M/ESPE), and Z-350 (3M/ESPE), cured at 25°C (no pre-heating) or 60°C (pre-heating). Specimens were stored sequentially in the following solutions: 1) water for 7 days (60°C), plus 0.1 N sodium hydroxide (NaOH) for 14 days (60°C); 2) 50% silver nitrate (AgNO3) for 10 days (60°C). Specimens were radiographed at baseline and after each storage time, and the images were evaluated in gray scale. After the storage protocol, samples were analyzed using SEM/EDS to check the depth of silver penetration. Radiopacity and silver penetration data were analyzed using ANOVA and Tukey's tests (α=5%). Results Radiopacity levels were as follows: Durafill VSZ-350>Z-250 (pheated specimens presented higher radiopacity values than non-pre-heated specimens (pheated specimens (pheating at 60°C mitigated the degradation of composites based on analysis of radiopacity and silver penetration depth.

Synthesis of Mo5SiB2 based nanocomposites by mechanical alloying and subsequent heat treatment

International Nuclear Information System (INIS)

Abbasi, A.R.; Shamanian, M.

2011-01-01

Research highlights: → α-Mo-Mo 5 SiB 2 nanocomposite was produced after 20 h milling of Mo-Si-B powders. → Heat treatment of 5 h MAed powders led to the formation of boride phases. → Heat treatment of 10 h MAed powders led to the formation of Mo 5 SiB 2 phase. → By increasing heat treatment time, quantity of Mo 5 SiB 2 phase increased. → 5 h heat treatment of 20 h MAed powders led to the formation of Mo 5 SiB 2 -based composite. - Abstract: In this study, systematic investigations were conducted on the synthesis of Mo 5 SiB 2 -based alloy by mechanical alloying and subsequent heat treatment. In this regard, Mo-12.5 mol% Si-25 mol% B powder mixture was milled for different times. Then, the mechanically alloyed powders were heat treated at 1373 K for 1 h. The phase transitions and microstructural evolutions of powder particles during mechanical alloying and heat treatment were studied by X-ray diffractometry and scanning electron microscopy. The results showed that the phase evolutions during mechanical alloying and subsequent heat treatment are strongly dependent on milling time. After 10 h of milling, a Mo solid solution was formed, but, no intermetallic phases were detected at this stage. However, an α-Mo-Mo 5 SiB 2 nanocomposite was formed after 20 h of milling. After heat treatment of 5 h mechanically alloyed powders, small amounts of MoB and Mo 2 B were detected and α-Mo-MoB-Mo 2 B composite was produced. On the other hand, heat treatment of 10 h and 20 h mechanically alloyed powders led to the formation of an α-Mo-Mo 5 SiB 2 -MoSi 2 -Mo 3 Si composite. At this point, there is a critical milling time (10 h) for the formation of Mo 5 SiB 2 phase after heat treatment wherein below that time, boride phase and after that time, Mo 5 SiB 2 phase are formed. In the case of 20 h mechanically alloyed powders, by increasing heat treatment time, not only the quantity of α-Mo was reduced and the quantity of Mo 5 SiB 2 was increased, but also new boride

Production of AA2124/MoSi{sub 2}/25p composites and effect of heat treatment on their microstructure, hardness and compression properties

Energy Technology Data Exchange (ETDEWEB)

Piyadeh, F.; Abdollah-Pour, H.; Lieblich, M.

2014-07-01

AA2124/25vol%MoSi{sub 2} composites were processed by two powder metallurgy routes: high energy ball milling of the reinforcement and alloy powder (B composite) and wet blending with cyclohexane (W composite), both followed by extrusion to achieve full consolidation. As-extruded and heat treated composite bars were studied microstructurally and mechanically (hardness and compression tests under quasistatic loading). Microstructure and fracture profiles were observed by scanning electron microscopy and the reaction products formed in the matrix were identified by energy-dispersive X-ray spectroscopy and X-ray diffraction analysis. The results show that for both composites, the hardness of the specimens in solution and aged condition was higher than in the as-extruded condition. The hardness of the B composite was higher than that of the W composite whereas the age-harden ability of the B composite was significantly lower than that of the W composite. After heat treatments, small diffusion reaction phases appeared at the interface between matrix and reinforcements. Compressive yield strength and the ultimate strength of both composites improved considerably after the artificial ageing. The composite fracture surfaces exhibited microscopically a ductile appearance that consisted of dimples in the matrix and a fragile fracture of the MoS{sub i}2 particulates. (Author)

THE EFFECTS OF INTERCRITICAL HEAT TREATMENTS ON THE ...

African Journals Online (AJOL)

Effect of intercritical heat treatment on 0.14wt%C 0.56wt%Mn 0.13wt%Si struc- ... Table 1: Chemical composition of the steel used (wt. %) with its critical temperature (calculated). C. Mn. Si. Ni. S ... primary austenitic grain size hardening and.

Heat release rate of wood-plastic composites

Science.gov (United States)

N. M. Stark; R. H. White; C. M. Clemons

1997-01-01

Wood-plastic composites are becoming more important as a material that fulfills recycling needs. In this study, fire performance tests were conducted on several compositions of wood and plastic materials using the Ohio State University rate of heat release apparatus. Test results included five-minute average heat release rate in kW/m2 (HRR avg) and maximum heat release...

High-Density Polyethylene and Heat-Treated Bamboo Fiber Composites: Nonisothermal Crystallization Properties

Directory of Open Access Journals (Sweden)

Yanjun Li

2015-01-01

Full Text Available The effect of heat-treated bamboo fibers (BFs on nonisothermal crystallization of high-density polyethylene (HDPE was investigated using differential scanning calorimetry under nitrogen. The Avrami-Jeziorny model was used to fit the measured crystallization data of the HDPE/BF composites and to obtain the model parameters for the crystallization process. The heat flow curves of neat HDPE and HDPE/heat-treated BF composites showed similar trends. Their crystallization mostly occurred within a temperature range between 379 K and 399 K, where HDPE turned from the liquid phase into the crystalline phase. Values of the Avrami exponent (n were in the range of 2.8~3.38. Lamellae of neat HDPE and their composites grew in a three-dimensional manner, which increased with increased heat-treatment temperature and could be attributed to the improved ability of heterogeneous nucleation and crystallization completeness. The values of the modified kinetic rate constant (KJ first increased and then decreased with increased cooling rate because the supercooling was improved by the increased number of nucleating sites. Heat-treated BF and/or a coupling agent could act as a nucleator for the crystallization of HDPE.

Relaxation of residual stress in MMC after combined plastic deformation and heat treatment

International Nuclear Information System (INIS)

Bruno, G.; Ceretti, M.; Girardin, E.; Giuliani, A.; Manescu, A.

2004-01-01

Neutron Diffraction shows that plastic pre-deformation and heat treatments have opposite effects on the residual stress in Al-SiC p composites. The thermal micro residual stress is relaxed or even reversed by pre-strains above 0.2%, but restored by heat treatments. The sense of relaxation changes above 400 deg. C (the mixing temperature)

Enhancement of heat dissipation of LED module with cupric-oxide composite coating on aluminum-alloy heat sink

International Nuclear Information System (INIS)

Kim, Donghyun; Lee, Junghoon; Kim, Junho; Choi, Chang-Hwan; Chung, Wonsub

2015-01-01

Highlights: • We fabricate the CuO/resin composite coating layer on aluminum alloy heat sink. • CuO/resin coating considerably improved the surface emissivity. • The LED junction temperature was reduced by CuO/resin coated heat sink. • The thermal resistance of heat sink was decreased by CuO/resin composite coating at 200 μm thickness. - Abstract: A composite coating composed of cupric oxide (CuO) and silicon-based resin was applied to an aluminum-alloy heat sink for a light emitting diode (LED) module. The purpose of the composite coating is to improve the heat dissipation performance of heat sink by enhancing thermal radiation emission. The heat dissipation performance was investigated in terms of LED junction temperature and thermal resistance using a thermal transient method. The CuO and silicon-based resin composite coating showed higher emissivity, and the lower junction temperature and thermal resistance of the heat sink was achieved. In addition, a continuous operation test of the LED chip with the heat sink revealed that the surface treated with the CuO composite coating stably dissipated heat without degradation. In conclusion, the composite coating proposed here showed a significant improvement of the heat dissipation performance of the aluminum-alloy heat sink due to the enhanced thermal radiation property.

Study of microstructure and superconducting properties of Nb3Al-tapes, obtained by heat treatment of three-layer and multilayer composites Nb/AlCu

International Nuclear Information System (INIS)

Korzhov, Valeriy P.

2012-01-01

The structure and superconductivity of three- and multilayer composite tapes of Nb/AlCu after high- temperature heating at 1750-1850 0 C for 1-3 seconds were investigated. Three-layer composites of Nb/AlCu/Nb with thickness of 50 microns were obtained by applying a vacuum rolling at 400-450 0 C and subsequent rolling at room temperature. Multilayer lengthy composites of Nb/AlCu obtained by extrusion with subsequent flattening by rolling of complex blank, collected in a special way. The effect of copper on the structure and properties of three-layer tapes was investigated. Copper increased the critical current of the superconductor. The critical current density in multilayered Nb 3 Al-tape reaches the value 8.10 4 A/cm 2 in magnetic field 14 T. The critical bending radius of the tape is 7 mm. Key words: multilayer composite tape, extrusion, rolling, superconducting Nb 3 Al-tape, high- temperature heat treatment, critical current density

Grain Refinement of Low Carbon Martensitic Steel by Heat Treatment

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N. V. Kolebina

2015-01-01

Full Text Available The low-carbon steels have good corrosion and technological properties. Hot deformation is the main operation in manufacturing the parts from these steels. So one of the important properties of the material is a property of plasticity. The grain size significantly influences on the ductility properties of steel. The grain size of steel depends on the chemical composition of the crystallization process, heat treatment, and steel machining. There are plenty methods to have grain refinement. However, taking into account the large size of the blanks for the hydro turbine parts, the thermal cycling is an advanced method of the grain refinement adaptable to streamlined production. This work experimentally studies the heat treatment influence on the microstructure of the low-carbon 01X13N04 alloy steel and proposes the optimal regime of the heat treatment to provide a significantly reduced grain size. L.M. Kleiner, N.P. Melnikov and I.N. Bogachyova’s works focused both on the microstructure of these steels and on the influence of its parameters on the mechanical properties. The paper focuses mainly on defining an optimal regime of the heat treatment for grain refinement. The phase composition of steel and temperature of phase transformation were defined by the theoretical analysis. The dilatometric experiment was done to determine the precise temperature of the phase transformations. The analysis and comparison of the experimental data with theoretical data and earlier studies have shown that the initial sample has residual stress and chemical heterogeneity. The influence of the heat treatment on the grain size was studied in detail. It is found that at temperatures above 950 ° C there is a high grain growth. It is determined that the optimal number of cycles is two. The postincreasing number of cycles does not cause further reducing grain size because of the accumulative recrystallization process. Based on the results obtained, the thermal cycling

Influence of heat treatment temperature on bonding and oxidation ...

Indian Academy of Sciences (India)

The effects of heat treatment temperature on the morphology, composition, chemical bonds, oxidation resistance and compressive strength of diamond particles coated with TiO2 films were characterized through scanning electron microscopy, Fourier transform infrared, Raman spectroscopy, X-ray diffraction analysis, X-ray ...

Influences of Thermo-Vacuum Treatment on Colors and Chemical Compositions of Alder Birch Wood

Directory of Open Access Journals (Sweden)

Yan Yang

2015-10-01

Full Text Available With high temperature-heat treatment, the dimensional stability and durability of wood is improved and wood color is darkened as well. In this paper, alder birch wood (Betula alnoides was treated by the Thermo-Vacuum Treatment (TVT. The changes of wood color parameters and the chemical composition were determined by the CIE1976 L*a*b* method and the chemical analysis method, respectively. The results were revealed as follows: (1 A lower value of lightness, L*, and a higher value of total color difference, △E*, were obtained at the higher heat-treatment temperatures and longer treatment time. (2 The higher the heat-treatment temperatures and the longer the heat-treatment times were, the lower the contents of hemicellulose and cellulose were and the higher the content of lignin was. Moreover, Fourier Transform infrared spectroscopy (FTIR analysis demonstrated that the characteristic absorption peaks of cellulose, hemicellulose, and lignin diminished. The acetylation reaction of hemicellulose and the degradation reaction of groups of lignin side chain occurred during TVT. (3 TVT degraded the chemical composition of cell walls, which resulted in further changes of the wood color. A significant correlation existed between the differences of color indices and the differences of the chemical composition after TVT.

Fatigue and frictional heating in ceramic matrix composites

DEFF Research Database (Denmark)

Jacobsen, T.K.; Sørensen, B.F.; Brøndsted, P.

1997-01-01

This paper describes an experimental technique for monitoring the damage evolution in ceramic matrix composites during cyclic testing. The damage is related to heat dissipation, which may be measured as radiated heat from the surface of the test specimen. In the present experimental set-up an iso......This paper describes an experimental technique for monitoring the damage evolution in ceramic matrix composites during cyclic testing. The damage is related to heat dissipation, which may be measured as radiated heat from the surface of the test specimen. In the present experimental set...... with a high spatial and temperature resolution and changes in the heat dissipation can be measured almost instantaneously. The technique has been tested on uni-directional ceramic matrix composites. Experimental results are shown and the possibilities and the limitations of the technique are discussed....

Effect of heat treatment on strength and abrasive wear behaviour of ...

Indian Academy of Sciences (India)

In the present investigation Al6061–SiCp composites was fabricated by liquid metallurgy route with percentages of SiCp varying from 4 wt% to 10 wt% in steps of 2 ... However, under identical heat treatment conditions, adopted Al6061–SiCp composites exhibited better microhardness and tensile strength reduced wear loss ...

Effect of heat treatment in air on surface composition of iron-phosphate based soft magnetic composite components

Energy Technology Data Exchange (ETDEWEB)

Oikonomou, C., E-mail: christos.oikonomou@chalmers.se; Oro, R.; Hryha, E.; Nyborg, L.

2014-11-15

Highlights: • Surface morphological and chemical depth profiling analyses of SMC parts. • Effect of annealing at exterior/interior areas for different temperature regimes. • Difference in degree of oxidation/nature of bulk/coating with area and temperature. • Thermodynamic calculations/considerations on the thermal stability of the coating. • Incomplete delubrication and strong bulk oxidation of the samples under 500 °C. - Abstract: Soft magnetic composite materials (SMC) manufactured by conventional powder metallurgical techniques for electromagnetic applications constitute individually encapsulated ferromagnetic powder particles with an insulating surface layer, bonded together into 3D finished structures. The production procedure includes compaction of the SMC base powder mixed with a lubricant substance and a post-annealing treatment that aims to relieve the stresses induced in the component during pressing. In the present study, the effect of the heat treatment process to the nature of the insulating layer was investigated under different temperature regimes using analytical techniques. Its surface chemistry was determined based on the XPS depth profiling technique, and its morphology and structure were evaluated using HR-SEM and XRD. Differences between interior and exterior areas of the samples suggested the development of an oxide scale in the outer regions that prevents its further bulk oxidation at temperatures above 500 °C, while below that temperature incomplete de-lubrication takes place.

Effects of heat treatment on the mechanical properties of kenaf fiber

Energy Technology Data Exchange (ETDEWEB)

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

2016-05-18

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

Study on the heat-resistant EB curing composites

International Nuclear Information System (INIS)

Bao Jianwen; Li Yang; Li Fengmei

2000-01-01

There are many advantages in the EB-curing process of composites. Heat-resistant EB-curing composites could substitute for polyimide composites used in aeronautical engine. The effects of catalyst and dose on the cured resin were investigated. The heat-resistance of the resin cured by EB was evaluated by dynamic mechanical thermal analysis (DMTA). The experiment result shows that the mechanical property of the composites cured by EB could meet the needs of the aeronautical engine in 250degC. (author)

An Analytical Solution for Transient Heat Conduction in a Composite Slab with Time-Dependent Heat Transfer Coefficient

Directory of Open Access Journals (Sweden)

Ryoichi Chiba

2018-01-01

Full Text Available An analytical solution is derived for one-dimensional transient heat conduction in a composite slab consisting of n layers, whose heat transfer coefficient on an external boundary is an arbitrary function of time. The composite slab, which has thermal contact resistance at n-1 interfaces, as well as an arbitrary initial temperature distribution and internal heat generation, convectively exchanges heat at the external boundaries with two different time-varying surroundings. To obtain the analytical solution, the shifting function method is first used, which yields new partial differential equations under conventional types of external boundary conditions. The solution for the derived differential equations is then obtained by means of an orthogonal expansion technique. Numerical calculations are performed for two composite slabs, whose heat transfer coefficient on the heated surface is either an exponential or a trigonometric function of time. The numerical results demonstrate the effects of temporal variations in the heat transfer coefficient on the transient temperature field of composite slabs.

Effect of the Heat Treatment on the Graphite Matrix of Fuel Element for HTGR

International Nuclear Information System (INIS)

Lee, Chungyong; Lee, Seungjae; Suh, Jungmin; Jo, Youngho; Lee, Youngwoo; Cho, Moonsung

2013-01-01

In this paper, the cylinder-formed fuel element for the block type reactor is focused on, which consists of the large part of graphite matrix. One of the most important properties of the graphite matrix is the mechanical strength for the high reliability because the graphite matrix should be enabled to protect the TRISO particles from the irradiation environment and the impact from the outside. In this study, the three kinds of candidate graphites and Phenol as a binder were chosen and mixed with each other, formed and heated for the compressive strength test. The objective of this research is to optimize the kinds and composition of the mixed graphite and the forming process by evaluating the compressive strength before/after heat treatment (carbonization of binder). In this study, the effect of heat treatment on graphite matrix was studied in terms of the density and the compressive strength. The size (diameter and length) of pellet is increased by heat treatment. Due to additional weight reduction and swelling (length and diameter) of samples the density of graphite pellet is decreased from about 2.0 to about 1.7g/cm 3 . From the mechanical test results, the compressive strength of graphite pellets was related to the various conditions such as the contents of binder, the kinds of graphite and the heat treatment. Both the green pellet and the heat treated pellet, the compressive strength of G+S+P pellets is relatively higher than that of R+S+P pellets. To optimize fuel element matrix, the effect of Phenol and other binders, graphite composition and the heat treatment on the mechanical properties will be deeply investigated for further study

Biochemical changes in full fat rice bran stabilized through microwave heating and irradiation treatment

International Nuclear Information System (INIS)

El-Niely, H.F.; Abaullah, M.I.

2007-01-01

The effect of microwave heating and irradiation treatments on proximate composition, lipoxygenase (LOX) activity, free fatty acid (FFA) and fatty acids profile of full fat rice bran were examined. Full fat raw rice bran (FRB) (82.7 g / kg moisture content) was heated in microwave oven at 850 W for up to 4 min or exposed to gamma irradiation up to 25 KGy then packed in polyethylene bags and stored at room temperature for 6 months. Water, protein, fat, ash and crude fiber contents did not change significantly in raw, microwave heated and irradiated samples before and after storage. An exception for this general observation was observed for the moisture content of FRB processed through microwave heating where heating FRB for 4 min dropped the level of moisture to 64.3 g / kg at zero time. Storage of both raw and processed samples had significant (P<0.05) effects on LOX activity. LOX activity of raw samples was significantly increased from its initial value by 43.5% after storage for six months. Microwave heat and irradiated samples showed deactivated LOX and samples exhibited significant changes in LOX activity could be due to treatment dosage. Meanwhile, significant change in LOX activity was observed in processed samples stored for six months. Minor changes were observed due to applied processing methods on FFA and fatty acids composition of full fat rice bran before and after storage. The results suggested that microwave heated or irradiated full fat rice bran packed in polyethylene bags can be stored at room temperature for six months without adverse effect on proximate, fatty acid composition quality and could prevent oxidative and hydrolytic rancidity. However, gamma irradiation treatment at 25 KGy was more effective in this respect. Therefore, it could be concluded that gamma irradiation contributed to optimal processing conditions for FRB stabilization

Silica Treatments: A Fire Retardant Strategy for Hemp Fabric/Epoxy Composites

Directory of Open Access Journals (Sweden)

Francesco Branda

2016-08-01

Full Text Available In this paper, for the first time, inexpensive waterglass solutions are exploited as a new, simple and ecofriendly chemical approach for promoting the formation of a silica-based coating on hemp fabrics, able to act as a thermal shield and to protect the latter from heat sources. Fourier Transform Infrared (FTIR and solid-state Nuclear Magnetic Resonance (NMR analysis confirm the formation of –C–O–Si– covalent bonds between the coating and the cellulosic substrate. The proposed waterglass treatment, which is resistant to washing, seems to be very effective for improving the fire behavior of hemp fabric/epoxy composites, also in combination with ammonium polyphosphate. In particular, the exploitation of hemp surface treatment and Ammonium Polyphosphate (APP addition to epoxy favors a remarkable decrease of the Heat Release Rate (HRR, Total Heat Release (THR, Total Smoke Release (TSR and Specific Extinction Area (SEA (respectively by 83%, 35%, 45% and 44% as compared to untreated hemp/epoxy composites, favoring the formation of a very stable char, as also assessed by Thermogravimetric Analysis (TGA. Because of the low interfacial adhesion between the fabrics and the epoxy matrix, the obtained composites show low strength and stiffness; however, the energy absorbed by the material is higher when using treated hemp. The presence of APP in the epoxy matrix does not affect the mechanical behavior of the composites.

Effect of heat treatment on strength and abrasive wear behaviour of ...

Indian Academy of Sciences (India)

Administrator

Aluminum 6061 has been used as matrix material owing to its ... Mechanical properties such as microhardness, tensile strength, and abrasive wear tests have been ... heat treatment conditions, adopted Al6061–SiCp composites exhibited better microhardness and tensile ... corrosion resistance (Ramesh et al 2005).

Effect of heat treatment of wood on the morphology, surface roughness and penetration of simulated and human blood.

Science.gov (United States)

Rekola, J; Lassila, L V J; Nganga, S; Ylä-Soininmäki, A; Fleming, G J P; Grenman, R; Aho, A J; Vallittu, P K

2014-01-01

Wood has been used as a model material for the development of novel fiber-reinforced composite bone substitute biomaterials. In previous studies heat treatment of wood was perceived to significantly increase the osteoconductivity of implanted wood material. The objective of this study was to examine some of the changing attributes of wood materials that may contribute to improved biological responses gained with heat treatment. Untreated and 140°C and 200°C heat-treated downy birch (Betula pubescens Ehrh.) were used as the wood materials. Surface roughness and the effect of pre-measurement grinding were measured with contact and non-contact profilometry. Liquid interaction was assessed with a dipping test using two manufactured liquids (simulated blood) as well as human blood. SEM was used to visualize possible heat treatment-induced changes in the hierarchical structure of wood. The surface roughness was observed to significantly decrease with heat treatment. Grinding methods had more influence on the surface contour and roughness than heat treatment. The penetration of the human blood in the 200°C heat-treated exceeded that in the untreated and 140°C heat-treated materials. SEM showed no significant change due to heat treatment in the dry-state morphology of the wood. The results of the liquid penetration test support previous findings in literature concerning the effects of heat treatment on the biological response to implanted wood. Heat-treatment has only a marginal effect on the surface contour of wood. The highly specialized liquid conveyance system of wood may serve as a biomimetic model for the further development of tailored fiber-composite materials.

Surface chemistry of polyacrylonitrile- and rayon-based activated carbon fibers after post-heat treatment

International Nuclear Information System (INIS)

Chiang Yuchun; Lee, C.-Y.; Lee, H.-C.

2007-01-01

Polyacrylonitrile- and rayon-based activated carbon fibers (ACFs) subject to heat treatment were investigated by means of elemental analyzer, and X-ray photoelectron spectroscopy (XPS). The total ash content of all ACFs was also analyzed. The adsorption of benzene, carbon tetrachloride and water vapor on ACFs was determined to shed light on the role of surface chemistry on gas adsorption. Results show that different precursors resulted in various elemental compositions and imposed diverse influence upon surface functionalities after heat treatment. The surface of heat-treated ACFs became more graphitic and hydrophobic. Three distinct peaks due to C, N, and O atoms were identified by XPS, and the high-resolution revealed the existence of several surface functionalities. The presence of nitride-like species, aromatic N-imines, or chemisorbed nitrogen oxides was found to be of great advantage to adsorption of water vapor or benzene, but the pyridine-N was not. Unstable complexes on the surface would hinder the fibers from adsorption of carbon tetrachloride. The rise in total ash content or hydrogen composition was of benefit to the access of water vapor. Modifications of ACFs by heat treatment have effectively improved adsorption performance

Effect of Heat Treatment on the Structure and Properties of Die Steel 70Kh3G2FTR

Science.gov (United States)

Krylova, S. E.; Kletsova, O. A.; Gryzunov, V. I.; Fot, A. P.; Tavtilov, I. Sh.

2018-01-01

The effect of heat treatment parameters on the properties and structural and phase composition of a promising die steel 70Kh3G2FTR for hot deformation is studied. The temperature-and-stress state of a hammer die under a heat treatment is simulated.

Effect of Heat Treatment and Salt Concentration on Free Amino Acids Composition of Sudanese Braided (Muddaffara Cheese during Storage

Directory of Open Access Journals (Sweden)

Mohamed O. E. Altahir

2014-07-01

Full Text Available The aim of this study was to assess the effect of heat treatment and salt concentrations (0, 5, and 10% on the free amino acids (FAA composition of Sudanese braided cheese (BC ripened for up to 3 months at 5±2°C. Heat and salt concentration significantly affected the FAA of braided cheese. The free amino acids concentrations of BC ripened in 0%, 5%, and 10% salted whey (SW were significantly fluctuated. Under ripening conditions tested (salt level + time, braided cheese made from pasteurized milk (BCPM had consistently lower values of FAA than braided cheese made from raw milk (BCRM. In fresh cheese, the major FAA in BCRM were Glu (36.12 nmol/ml, Leu (26.77nmol/ml and Lys (14.51 nmol/ml while the major ones in BCPM were Lys (2.94 nmol/ml and Ala (2.45 nmol/ml. BCPM stored in 10% SW had shorter quality life compared to that stored in 5% salted whey.

Effect of Heat Treatment Temperature on Chemical Compositions of Extracted Hydroxyapatite from Bovine Bone Ash

Science.gov (United States)

Younesi, M.; Javadpour, S.; Bahrololoom, M. E.

2011-11-01

This article presents the effect of heat treating temperature on chemical composition of hydroxyapatite (HA) that was produced by burning bovine bone, and then heat treating the obtained bone ash at different temperatures in range of 600-1100 °C in air. Bone ash and the resulting white powder from heat treating were characterized by Fourier transformed infrared spectroscopy (FT-IR) and x-ray diffractometry (XRD). The FT-IR spectra confirmed that heat treating of bone ash at temperature of 800 °C removed the total of organic substances. x-ray diffraction analysis showed that the white powder was HA and HA was the only crystalline phase indicated in heat treating product. x-ray fluorescence analyses revealed that calcium and phosphorous were the main elements and magnesium and sodium were minor impurities of produced powder at 800 °C. The results of the energy dispersive x-ray analysis showed that Ca/P ratio in produced HA varies in range of 1.46-2.01. The resulting material was found to be thermally stable up to 1100 °C.

Electrodeposition of Copper/Carbonous Nanomaterial Composite Coatings for Heat-Dissipation Materials

Directory of Open Access Journals (Sweden)

Yasuki Goto

2017-12-01

Full Text Available Carbonous nanomaterials are promising additives for composite coatings for heat-dissipation materials because of their excellent thermal conductivity. Here, copper/carbonous nanomaterial composite coatings were prepared using nanodiamond (ND as the carbonous nanomaterial. The copper/ND composite coatings were electrically deposited onto copper substrates from a continuously stirred copper sulfate coating bath containing NDs. NDs were dispersed by ultrasonic treatment, and the initial bath pH was adjusted by adding sodium hydroxide solution or sulfuric acid solution before electrodeposition. The effects of various coating conditions—the initial ND concentration, initial bath pH, stirring speed, electrical current density, and the amount of electricity—on the ND content of the coatings were investigated. Furthermore, the surface of the NDs was modified by hydrothermal treatment to improve ND incorporation. A higher initial ND concentration and a higher stirring speed increased the ND content of the coatings, whereas a higher initial bath pH and a greater amount of electricity decreased it. The electrical current density showed a minimum ND content at approximately 5 A/dm2. Hydrothermal treatment, which introduced carboxyl groups onto the ND surface, improved the ND content of the coatings. A copper/ND composite coating with a maximum of 3.85 wt % ND was obtained.

The effect of heat treatment on microstructure evolution in artificially aged carbon nanotube/Al2024 composites synthesized by mechanical alloying

International Nuclear Information System (INIS)

Pérez-Bustamante, R.; Pérez-Bustamante, F.; Maldonado-Orozco, M.C.; Martínez-Sánchez, R.

2017-01-01

Although carbon nanotubes/aluminum (CNT/Al) composites are promising materials in the production of structural components, their mechanical behavior under overaging conditions has not been considered. In this paper the effect of CNTs on the microstructural and mechanical behavior of a 2024 aluminum alloy (Al2024) synthesized by mechanical alloying (MA) and powder metallurgy routes is discussed, as well as the effect of aging heat treatments at different temperatures and aging times. The mechanical behavior of composites was screened by hardness measurements as function of aging time. After 96 h of aging time, composites showed mechanical stability in their hardness performance. Images from transmission electron microscopy showed that the mechanical stability of composites was due to a homogeneous dispersion of CNTs in the aluminum matrix and a subsequent alteration in the kinetics of precipitation is due to their presence in the aluminum matrix. Even though strengthening precipitation took place during aging, this was not the main strengthening mechanism observed in composites. - Highlights: • Dispersion of carbon nanotubes during mechanical alloying • Microstructural evolution observed by HRTEM. • Mechanical performance evaluated through micro-hardness test. • Increased mechanical performance at high working temperatures • Acceleration of kinetics of precipitation due to CNTs, and milling conditions

The effect of heat treatment on microstructure evolution in artificially aged carbon nanotube/Al2024 composites synthesized by mechanical alloying

Energy Technology Data Exchange (ETDEWEB)

Pérez-Bustamante, R. [Centro de Investigación en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnología, Miguel de Cervantes No.120, C.P. 31109 Chihuahua, Chih. (Mexico); Pérez-Bustamante, F. [Universidad Autónoma de Chihuahua (UACH), Facultad de Ciencias Químicas, Circuito No. 1 Nuevo Campus Universitario, C.P. 31125 Chihuahua, Chih. (Mexico); Maldonado-Orozco, M.C. [Universidad Autónoma de Chihuahua (UACH), Facultad de Ingeniería, Circuito No. 1 Nuevo Campus Universitario, C.P. 31125 Chihuahua, Chih. (Mexico); Martínez-Sánchez, R., E-mail: roberto.martinez@cimav.edu.mx [Centro de Investigación en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnología, Miguel de Cervantes No.120, C.P. 31109 Chihuahua, Chih. (Mexico)

2017-04-15

Although carbon nanotubes/aluminum (CNT/Al) composites are promising materials in the production of structural components, their mechanical behavior under overaging conditions has not been considered. In this paper the effect of CNTs on the microstructural and mechanical behavior of a 2024 aluminum alloy (Al2024) synthesized by mechanical alloying (MA) and powder metallurgy routes is discussed, as well as the effect of aging heat treatments at different temperatures and aging times. The mechanical behavior of composites was screened by hardness measurements as function of aging time. After 96 h of aging time, composites showed mechanical stability in their hardness performance. Images from transmission electron microscopy showed that the mechanical stability of composites was due to a homogeneous dispersion of CNTs in the aluminum matrix and a subsequent alteration in the kinetics of precipitation is due to their presence in the aluminum matrix. Even though strengthening precipitation took place during aging, this was not the main strengthening mechanism observed in composites. - Highlights: • Dispersion of carbon nanotubes during mechanical alloying • Microstructural evolution observed by HRTEM. • Mechanical performance evaluated through micro-hardness test. • Increased mechanical performance at high working temperatures • Acceleration of kinetics of precipitation due to CNTs, and milling conditions.

TEM Characterization and Properties of Cu-1 wt.% TiB2 Nanocomposite Prepared by Rapid Solidification and Subsequent Heat Treatment

Directory of Open Access Journals (Sweden)

M. Sobhani

2012-12-01

Full Text Available Copper matrix composite reinforced by 1wt.% TiB2 particles was prepared using in situ reaction of Cu-1.4wt.% Ti and Cu-0.7wt.% B by rapid solidification and subsequent heat treatment for 1-20 hrs at 900ºC. High-resolution transmission electron microscopy (HRTEM characterization showed that primary TiB2 particles were formed in liquid copper. Heat treatment of as-solidified samples led to the formation of secondary TiB2 particles via spinodal decomposition of titanium-rich zone inside the grains. Mechanical properties (after 50% reduction in area as well as electrical conductivity of composite were evaluated after heat treatment and were compared with those of pure copper. The results indicated that, due to the formation of secondary TiB2 particles in the matrix, electrical conductivity increased along with hardness up to 10 hrs of heat treatment and reached 65% IACS and 155 HV, respectively. Moreover, the maximum ultimate (i.e. 580 MPa and yield (i.e. 555 MPa strengths of composite were achieved at this time.

Effect of T6 heat treatment on damping characteristics of Al/RHA ...

Indian Academy of Sciences (India)

Abstract. In the present work, effect of T6 heat treatment on the damping behaviour of aluminum/rice husk ash .... alloy-based composites, there is dearth of information on the damping ... fication. Using the process 4, 6 and 8% by weight, RHA.

INFLUENCE OF SILANE HEAT TREATMENT ON THE TENSILE BOND STRENGTH BETWEEN EX-3 SYNTHETIC VENEERING PORCELAIN AND COMPOSITE RESIN USING FIVE DIFFERENT ACTIVATION TEMPERATURES

Directory of Open Access Journals (Sweden)

Spartak Yanakiev

2017-02-01

Full Text Available Purpose: The purpose of the present study is to assess the effect of five different silane activation temperatures and eight activation methods on the tensile bond strength between one veneering porcelain and one composite resin material. Material and methods: A total of 81 ceramic rods were made of EX-3 veneering ceramic (Kuraray Noritake Dental, Japan. Sintered ceramic bars were grinded with diamond disks to size 10x2x2mm ± 0,05mm. The front part of each bar was polished. After ultrasonic cleaning in distilled water, the specimens were divided into nine groups. Silane was activated with air at room temperature, 38º С, 50º С, 100º С, 120º С using a custom made blow drier. In a silicone mold, a composite resin Z250 (3М ESPE, St. Paul, USA was condensed toward the bond ceramic surface. A total of 81 specimens approximately 2,0 cm long were prepared for tensile bond testing. One way ANOVA, followed by Bonferroni and Games-Howell tests were used for statistical analysis. Results: The lowest tensile bond strength was observed in the control group (3,51MPa. Group 2 yielded the highest bond strength among all groups (19,54MPa. Silane heat treatment enhanced the bond strength for all treatment methods. Within the polished specimens, the highest bond strength was yielded with warm air at 120ºС (11,31MPa. Conclusion: The most effective method for bonding Z250 composite resin to EX-3 veneering ceramic includes HF etching, silane, and adhesive resin. The most effective heat treatment method for bonding is hot air at 120ºС.

THE INFLUENCE OF PRE-HEAT TREATMENT ON WHITE CAST IRONS PLASTICITY

Directory of Open Access Journals (Sweden)

T. M. Myronova

2013-11-01

Full Text Available Purpose. The development of heat treatment modes of white cast irons for structure changes in their eutectic constituent, namely in disturbing the monolithic structure of ledeburite colonies cementite structure and eutectic net continuity. Also the mentioned heat treatment modes are targeted to the eutectic net shift for the most suitable position from the point of plastic deforming. Methodology. The hypoeutectic white cast irons with 2.92…3.35 % carbon content and additionally alloyed by 3.18 % vanadium have been used as the research materials. The mentioned alloys have been pre-heat treated and hot twist tested. Findings. The research results showed that the carbide net breaking by plastic deforming leads to cast irons mechanical properties increasing but has difficulties in implementation due to the white cast irons low plasticity. The influence of different pre-heat treatment modes on structure and plasticity of white hypoeutectic cast irons have been investigated. They include the isotherm soaking under the different temperatures as well as multiply soakings and thermo-cycling. The influence of eutectic level, as well as pre heat treatment modes on different composition white cast irons hot plasticity have been investigated. Originality. It was determined that the heat treatment, which leads to double α→γ recrystallization under 860 – 950 °С and reperlitization under 720-680 °С results in significant increase of plasticity, as well as in un-alloyed and alloyed by vanadium white cast irons. It takes place due to carbide matrix phase separation in ledeburite colonies by new phase boundaries forming especially due to carbide transformations under vanadium alloying. Practical value. The implementation of pre-heat treatment with phase recrystallization resulted in hypoeutectic white cast irons plasticity increasing. The obtained level of cast iron plasticity corresponds to the one of carbide class steels, which ensures the successful

29 CFR 1919.36 - Heat treatment.

Science.gov (United States)

2010-07-01

... 29 Labor 7 2010-07-01 2010-07-01 false Heat treatment. 1919.36 Section 1919.36 Labor Regulations...) GEAR CERTIFICATION Certification of Vessels: Tests and Proof Loads; Heat Treatment; Competent Persons § 1919.36 Heat treatment. (a) The annealing of wrought iron gear required by this part shall be...

49 CFR 179.500-6 - Heat treatment.

Science.gov (United States)

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Heat treatment. 179.500-6 Section 179.500-6...-6 Heat treatment. (a) Each necked-down tank shall be uniformly heat treated. Heat treatment shall... treatment of alternate steels shall be approved. All scale shall be removed from outside of tank to an...

29 CFR 1919.80 - Heat treatment.

Science.gov (United States)

2010-07-01

... 29 Labor 7 2010-07-01 2010-07-01 false Heat treatment. 1919.80 Section 1919.80 Labor Regulations...) GEAR CERTIFICATION Certification of Shore-Based Material Handling Devices § 1919.80 Heat treatment. (a) Wherever heat treatment of any loose gear is recommended by the manufacturer, it shall be carried out in...

Heat Transfer Analysis of Localized Heat-Treatment for Grade 91 Steel

Science.gov (United States)

Walker, Jacob D.

Many of the projects utilizing Grade 91 steel are large in scale, therefore it is necessary to assemble on site. The assembly of the major pieces requires welding in the assembly; this drastically changes the superior mechanical properties of Grade 91 steel that it was specifically developed for. Therefore, because of the adverse effects of welding on the mechanical properties of Grade 91, it is necessary to do a localized post weld heat treatment. As with most metallic materials grade 91 steel requires a very specific heat treatment process. This process includes a specific temperature and duration at that temperature to achieve the heat treatment desired. Extensive research has been done to determine the proper temperatures and duration to provide the proper microstructure for the superior mechanical properties that are inherent to Grade 91 steel. The welded sections are typically large structures that require local heat treatments and cannot be placed in an oven. The locations of these structures vary from indoors in a controlled environment to outdoors with unpredictable environments. These environments can be controlled somewhat, however in large part the surrounding conditions are unchangeable. Therefore, there is a need to develop methods to accurately apply the surrounding conditions and geometries to a theoretical model in order to provide the proper requirements for the local heat treatment procedure. Within this requirement is the requirement to define unknowns used in the heat transfer equations so that accurate models can be produced and accurate results predicted. This study investigates experimentally and numerically the heat transfer and temperature fields of Grade 91 piping in a local heat treatment. The objective of this thesis research is to determine all of the needed heat transfer coefficients. The appropriate heat transfer coefficients are determined through the inverse heat conduction method utilizing a ceramic heat blanket. This will be done

In situ heat treatment process utilizing a closed loop heating system

Science.gov (United States)

Vinegar, Harold J.; Nguyen, Scott Vinh

2010-12-07

Systems and methods for an in situ heat treatment process that utilizes a circulation system to heat one or more treatment areas are described herein. The circulation system may use a heated liquid heat transfer fluid that passes through piping in the formation to transfer heat to the formation. In some embodiments, the piping may be positioned in at least two of the wellbores.

Heat Generation by Irradiated Complex Composite Nanostructures

DEFF Research Database (Denmark)

Ma, Haiyan; Tian, Pengfei; Pello, Josselin

2014-01-01

Heating of irradiated metallic e-beam generated nanostructures was quantified through direct measurements paralleled by novel model-based numerical calculations. By comparing discs, triangles, and stars we showed how particle shape and composition determines the heating. Importantly, our results...... revealed that substantial heat is generated in the titanium adhesive layer between gold and glass. Even when the Ti layer is as thin as 2 nm it absorbs as much as a 30 nm Au layer and hence should not be ignored....

Optimized chemical composition, working and heat treatment condition for resistance to irradiation assisted stress corrosion cracking of cold worked 316 and high-chromium austenitic stainless steel

International Nuclear Information System (INIS)

Yonezawa, Toshio; Iwamura, Toshihiko; Fujimoto, Koji; Ajiki, Kazuhide

2000-01-01

The authors have reported that the primary water stress corrosion cracking (PWSCC) in baffle former bolts made of austenitic stainless steels for PWR after long-term operation is caused by irradiation-induced grain boundary segregation. The resistance to PWSCC of simulated austenitic stainless steels whose chemical compositions are simulated to the grain boundary chemical composition of 316 stainless steel after irradiation increased with decrease of the silicon content, increases of the chromium content, and precipitation of M 23 C 6 carbides at the grain boundaries. In order to develop resistance to irradiation assisted stress corrosion cracking in austenitic stainless steels, optimized chemical compositions and heat treatment conditions for 316CW and high-chromium austenitic stainless steels for PWR baffle former bolts were investigated. For 316CW stainless steel, ultra-low-impurities and high-chromium content are beneficial. About 20% cold working before aging and after solution treatment has also been recommended to recover sensitization and make M 23 C 6 carbides coherent with the matrix at the grain boundaries. Heating at 700 to 725degC for 20 to 50 h was selected as a suitable aging procedure. Cold working of 5 to 10% after aging produced the required mechanical properties. The optimized composition of the high-chromium austenitic stainless steel contents 30% chromium, 30% nickel, and ultra-low impurity levels. This composition also reduces the difference between its thermal expansion coefficient and that of 304 stainless steel for baffle plates. Aging at 700 to 725degC for longer than 40 h and cold working of 10 to 15% after aging were selected to meet mechanical property specifications. (author)

Effect of heat treatment and composition on stress corrosion cracking of steam generation tubing materials

International Nuclear Information System (INIS)

Kim, H. P.; Hwang, S. S.; Kuk, I. H.; Kim, J. S.; Oh, C. Y.

1998-01-01

Effects of heat treatment and alloy composition on stress corrosion cracking (SCC) of steam generator tubing materials have been studied in 40% NaOH at 315.deg.C at potential of +200mV above corrosion potential using C-ring specimen and reverse U bend specimen. The tubing materials used were commercial Alloy 600, Alloy 690 and laboratory alloys, Ni-χCr-10Fe. Commercial Alloy 600, Alloy 690 were mill annealed or thermally treated.Laboratory alloy Ni-χCr-10Fe, and some of Alloy 600 and Alloy 690 were solution annealed. Polarization curves were measured to find out any relationship between SCC susceptibility and electrochemical behaviour. The variation in thermal treatment of Alloy 600 and Alloy 690 had no effect on polarization behaviour probably due to small area fraction of carbide and Cr depletion zone near grain boundary. In anodic polarization curves, the first and second anodic peaks at about 170mV and about at 260mV, respectively, above corrosion potential were independent of Cr content, whereas the third peak at 750mV above corrosion potential and passive current density in-creased with Cr content. SCC susceptibility decreased with Cr content and thermal treatment producing semicontinuous grain boundary decoration. Examination of cross sectional area of C-ring specimen showed deep SCC cracks for the alloys with less than 17%Cr and many shallow attacks for alloy 690. The role of Cr content in steam generator tubing materials and grain boundary carbide on SCC were discussed

Thermoluminescence and cathodoluminescence studies of calcite and MgO: surface defects and heat treatment

International Nuclear Information System (INIS)

Goeksu, H.Y.; Brown, L.M.

1988-01-01

Some of the problems which preclude accurate thermoluminescence (TL) dating of geologically formed calcite stem from different sample pre-treatment procedures, such as grinding, drilling or pre-heating. It has long been known that grinding can introduce spurious TL in calcite, but there have been wide differences of opinion as to the magnitude of the influence and its importance. Therefore, various grinding and acid-washing procedures have been suggested to avoid spurious thermoluminescence. Various models have been developed to explain the mechanism. We have studied the changes in thermoluminescence (TL) and cathodoluminescence (CL) properties as well as in the spectral composition of the glow from calcite and MgO due to surface defects and heat treatment. It is found that both laboratory heat treatment and surface indents give rise to changes in TL efficiency. (author)

Effect of heat treatment on carbon fiber surface properties and fibers/epoxy interfacial adhesion

International Nuclear Information System (INIS)

Dai Zhishuang; Zhang Baoyan; Shi Fenghui; Li Min; Zhang Zuoguang; Gu Yizhuo

2011-01-01

Carbon fiber surface properties are likely to change during the molding process of carbon fiber reinforced matrix composite, and these changes could affect the infiltration and adhesion between carbon fiber and resin. T300B fiber was heat treated referring to the curing process of high-performance carbon fiber reinforced epoxy matrix composites. By means of X-ray photoelectron spectroscopy (XPS), activated carbon atoms can be detected, which are defined as the carbon atoms conjunction with oxygen and nitrogen. Surface chemistry analysis shows that the content of activated carbon atoms on treated carbon fiber surface, especially those connect with the hydroxyl decreases with the increasing heat treatment temperature. Inverse gas chromatography (IGC) analysis reveals that the dispersive surface energy γ S d increases and the polar surface energy γ S sp decreases as the heat treatment temperature increases to 200. Contact angle between carbon fiber and epoxy E51 resin, which is studied by dynamic contact angle test (DCAT) increases with the increasing heat treatment temperature, indicating the worse wettability comparing with the untreated fiber. Moreover, micro-droplet test shows that the interfacial shear strength (IFSS) of the treated carbon fiber/epoxy is lower than that of the untreated T300B fiber which is attributed to the decrement of the content of reactive functional groups including hydrogen group and epoxy group.

Heat treatment of transparent Yb:YAG and YAG ceramics and its influence on laser performance

Science.gov (United States)

Fujioka, Kana; Mochida, Tetsuo; Fujimoto, Yasushi; Tokita, Shigeki; Kawanaka, Junji; Maruyama, Momoko; Sugiyama, Akira; Miyanaga, Noriaki

2018-05-01

Composite transparent ceramic materials are promising for improving the performance of high-average-power lasers. A combination of room-temperature bonding via surface treatment by a fast atom beam and diffusion bonding via heating, which effectively controls the ion diffusion distance near the interface, makes the laser materials suitable for a variety of oscillator/amplifier. During the heat treatment of yttrium aluminum garnet (YAG) ceramics, the Si ions in the solid solution of the sintering aid incorporated within the grains were seen to segregate at the grain boundary, resulting in an increase of scattering sites. The number density and size of the scattering sites strongly depended on the post-heating temperature rather than the heating time. Specifically, heating at 1300 °C did not affect the transmittance of the YAG ceramic, whereas both the size and number of scattering sites substantially increased with a heat treatment at 1400 °C. The laser oscillation experiment using cryogenically-cooled Yb:YAG ceramics exhibited heating temperature dependence of the slope efficiency owing to the increasing scattering loss.

49 CFR 179.400-12 - Postweld heat treatment.

Science.gov (United States)

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Postweld heat treatment. 179.400-12 Section 179... and 107A) § 179.400-12 Postweld heat treatment. (a) Postweld heat treatment of the inner tank is not... be attached before postweld heat treatment. Welds securing the following need not be postweld heat...

Heat-treatment and heat-to-heat variations in the fracture toughness of Alloy 718

International Nuclear Information System (INIS)

Mills, W.J.

1981-07-01

The effect of heat-treatment and heat-to-heat variations on the J Ic fracture toughness response of Alloy 718 was examined at room and elevated temperatures using the multiple-specimen R-curve technique. Six heats of alloy 718 were tested in the conventional and modified heat-treated conditions. The fracture toughness response for the modified superalloy was found to be superior to that exhibited by the conventional material. Heat-to-heat variations in the J Ic response of Alloy 718 were observed in both heat-treated conditions; the modified treatment exhibited much larger variability. The J Ic and corresponding K Ic fracture toughness values were analyzed statistically to establish minimum expected toughness, values for use in design and safety analyses. 26 refs., 10 figs., 9 tabs

Fully coupled heat conduction and deformation analyses of nonlinear viscoelastic composites

KAUST Repository

Khan, Kamran

2012-05-01

This study presents an integrated micromechanical model-finite element framework for analyzing coupled heat conduction and deformations of particle-reinforced composite structures. A simplified micromechanical model consisting of four sub-cells, i.e., one particle and three matrix sub-cells is formulated to obtain the effective thermomechanical properties and micro-macro field variables due to coupled heat conduction and nonlinear thermoviscoelastic deformation of a particulate composite that takes into account the dissipation of energy from the viscoelastic constituents. A time integration algorithm for simultaneously solving the equations that govern heat conduction and thermoviscoelastic deformations of isotropic homogeneous materials is developed. The algorithm is then integrated to the proposed micromechanical model. A significant temperature generation due to the dissipation effect in the viscoelastic matrix was observed when the composite body is subjected to cyclic mechanical loadings. Heat conduction due to the dissipation of the energy cannot be ignored in predicting the factual temperature and deformation fields within the composite structure, subjected to cyclic loading for a long period. A higher creep resistant matrix material or adding elastic particles can lower the temperature generation. Our analyses suggest that using particulate composites and functionally graded materials can reduce the heat generation due to energy dissipation. © 2012 Elsevier Ltd.

49 CFR 179.220-11 - Postweld heat treatment.

Science.gov (United States)

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Postweld heat treatment. 179.220-11 Section 179... Postweld heat treatment. (a) Postweld heat treatment of the inner container is not a specification requirement. (b) Postweld heat treatment of the cylindrical portions of the outer shell to which the anchorage...

Process for forming thin film, heat treatment process of thin film sheet, and heat treatment apparatus therefor

International Nuclear Information System (INIS)

Watanabe, S.

1984-01-01

The invention provides a process for forming a magnetic thin film on a base film, a heat treatment process of a thin film sheet consisting of the base film and the magnetic thin film, and an apparatus for performing heat treatment of the thin film sheet. Tension applied to the thin film sheet is substantially equal to that applied to the base film when the magnetic thin film is formed thereon. Then, the thin film sheet is treated with heat. The thin film sheet is heated with a given temperature gradient to a reactive temperature at which heat shrinkage occurs, while the tension is being applied thereto. Thereafter, the thin film sheet to which the tension is still applied is cooled with substantially the same temperature gradient as applied in heating. The heat treatment apparatus has a film driving unit including a supply reel, a take-up reel, a drive source and guide rollers; a heating unit including heating plates, heater blocks and a temperature controller for heating the sheet to the reactive temperature; and a heat insulating unit including a thermostat and another temperature controller for maintaining the sheet at the nonreactive temperature which is slightly lower than the reactive temperature

Development of glass fibre reinforced composites using microwave heating technology

Science.gov (United States)

Köhler, T.; Vonberg, K.; Gries, T.; Seide, G.

2017-10-01

Fibre reinforced composites are differentiated by the used matrix material (thermoplastic versus duroplastic matrix) and the level of impregnation. Thermoplastic matrix systems get more important due to their suitability for mass production, their good shapeability and their high impact resistance. A challenge in the processing of these materials is the reduction of the melt flow paths of the thermoplastic matrix. The viscosity of molten thermoplastic material is distinctly higher than the viscosity of duroplastic material. An approach to reduce the flow paths of the thermoplastic melt is given by a commingling process. Composites made from commingling hybrid yarns consist of thermoplastic and reinforcing fibres. Fabrics made from these hybrid yarns are heated and consolidated by the use of heat pressing to form so called organic sheets. An innovative heating system is given by microwaves. The advantage of microwave heating is the volumetric heating of the material, where the energy of the electromagnetic radiation is converted into thermal energy inside the material. In this research project microwave active hybrid yarns are produced and examined at the Institute for Textile Technology of RWTH Aachen University (ITA). The industrial research partner Fricke und Mallah Microwave Technology GmbH, Peine, Germany develops an innovative pressing systems based on a microwave heating system. By implementing the designed microwave heating technology into an existing heat pressing process, FRTCs are being manufactured from glass and nanomodified polypropylene fibre woven fabrics. In this paper the composites are investigated for their mechanical and optical properties.

Viscoelastic characterization and self-heating behavior of laminated fiber composite driveshafts

International Nuclear Information System (INIS)

Henry, Todd C.; Bakis, Charles E.; Smith, Edward C.

2015-01-01

Highlights: • Carbon fiber composites with different matrix moduli were manufactured. • The composites are of interest for flexible driveshaft applications. • The composites are viscoelastically characterized using dynamic mechanical analysis. • The viscoelastic properties are used to predict self-heating in spinning shafts. • Measured and predicted temperatures of shafts agreed within 0.7 °C. - Abstract: The high cyclic strain capacity of fiber reinforced polymeric composites presents an opportunity to design driveshafts that can transmit high power under imperfect alignment conditions without the use of flexible couplers. In weight sensitive applications such as rotorcraft, the design of highly optimized driveshafts requires a general modeling capability that can predict a number of shaft performance characteristics—one of which is self-heating due to dynamic loading conditions. The current investigation developed three new flexible matrix composite materials of intermediate matrix modulus that, together with previously developed composites, cover the full range of material properties that are of potential interest in driveshaft design. An analytical model for the self-heating of spinning, misaligned, laminated composite shafts was refined to suit the full range of materials. Inputs to the model include ply-level dynamic material properties of the composite, cyclic strain amplitude and frequency, and various heat transfer constants related to conduction, radiation, and convection. Predictions of the surface temperature of spinning shafts correspond well with experimental measurements for bending strains of up to 2000 με, which encompasses the range of strains expected in rotorcraft driveshaft applications

Preparation and characterization of composite microspheres for brachytherapy and hyperthermia treatment of cancer

International Nuclear Information System (INIS)

Zhao Di; Huang Wenhai; Rahaman, Mohamed N.; Day, Delbert E.; Wang Deping; Gu Yifei

2012-01-01

Composite microspheres were prepared by coating yttrium–aluminum–silicate (YAS) glass microspheres (20–30 μm) with a layer of Fe 3 O 4 nanoparticles and evaluated for potential use in brachytherapy and hyperthermia treatment of cancer. After neutron activation to form the β-emitting 90 Y radionuclide, the composite microspheres can be injected into a patient to destroy cancerous tumors; at the same time, the composite microspheres can generate heat upon application of a magnetic field to also destroy the tumors. The results showed that the composite microspheres were chemically durable when immersed in a simulated body fluid (SBF), with ∼ 0.25% weight loss and ∼ 3.2% yttrium dissolved into the SBF after 30 days at 37 °C. The composite microspheres also showed ferromagnetic properties as a result of the Fe 3 O 4 coating; when immersed in water at 20 °C (20 mg in 1 mL of water), the application of an alternating magnetic field produced a temperature increase from 20 °C to 38−46 °C depending on the thickness of the Fe 3 O 4 coating. The results indicate that these composite microspheres have promising potential in combined brachytherapy and hyperthermia treatment of cancerous tumors. - Highlights: ► Composite microspheres for brachytherapy and hyperthermia treatment of cancer. ► Fe 3 O 4 nanoparticles coated on the yttrium–aluminum–silicate glass microspheres. ► Microspheres are chemically stable in SBF. ► Microspheres can generate heat for hyperthermia under an alternating magnetic field. ► Microspheres can emit β-rays for brachytherapy after neutron activation.

Evaluation of Criticality of Self-Heating of Polymer Composites by Estimating the Heat Dissipation Rate

Science.gov (United States)

Katunin, A.

2018-03-01

The critical self-heating temperature at which the structural degradation of polymer composites under cyclic loading begins is evaluated by analyzing the heat dissipation rate. The method proposed is an effective tool for evaluating the degradation degree of such structures.

Heat treatment furnace

Science.gov (United States)

Seals, Roland D; Parrott, Jeffrey G; DeMint, Paul D; Finney, Kevin R; Blue, Charles T

2014-10-21

A furnace heats through both infrared radiation and convective air utilizing an infrared/purge gas design that enables improved temperature control to enable more uniform treatment of workpieces. The furnace utilizes lamps, the electrical end connections of which are located in an enclosure outside the furnace chamber, with the lamps extending into the furnace chamber through openings in the wall of the chamber. The enclosure is purged with gas, which gas flows from the enclosure into the furnace chamber via the openings in the wall of the chamber so that the gas flows above and around the lamps and is heated to form a convective mechanism in heating parts.

A stydy on the heat transfer characteristics in the composite heat pipe as modeling turbine rotor

International Nuclear Information System (INIS)

Kwon, Sun Sok; Jang, Yeong Suc; Yoo, Byung Wook

1993-01-01

The purpose of this research is to study the characteristics of heat transfer in composite rotary heat pipe as modeled turbine rotating by a finite element analysis and experiment. Nu number, Re number, Pr number and dimensionless condensate layer thickness by thermal input and revolutions per minute were given as analysis factors. The comparison between calculated and experimental data showed similar tendency. Therefore the analysis method may be useful to predict the performance of composite heat pipe. The resistance on heat pipe showed the best effect of heat transfer by film condensation, by decreasing film condensation, the heat transfer rate from condenser was increased rapidly. The dimensionless condensate layer thickness according to Re number at given Pr number showed constant values, the dimensionless condensate layer thickness is proportionate to the square root of inverse of revolution number per minute. In this study Nu = A(δ(ω/ν) -1/2 Re B ) is used to the convection heat transfer coefficient and A = 0.963, B = 0.5025 were obtained as analysis predicts. (Author)

Plasma assisted heat treatment: annealing

International Nuclear Information System (INIS)

Brunatto, S F; Guimaraes, N V

2009-01-01

This work comprises a new dc plasma application in the metallurgical-mechanical field, called plasma assisted heat treatment, and it presents the first results for annealing. Annealing treatments were performed in 90% reduction cold-rolled niobium samples at 900 deg. C and 60 min, in two different heating ways: (a) in a hollow cathode discharge (HCD) configuration and (b) in a plasma oven configuration. The evolution of the samples' recrystallization was determined by means of the microstructure, microhardness and softening rate characterization. The results indicate that plasma species (ions and neutrals) bombardment in HCD plays an important role in the recrystallization process activation and could lead to technological and economical advantages considering the metallic materials' heat treatment application. (fast track communication)

The Effect of Heat Treatments and Coatings on the Outgassing Rate of Stainless Steel Chambers

Energy Technology Data Exchange (ETDEWEB)

Mamum, Md Abdullah A. [Old Dominion Univ., Norfolk, VA (United States); Elmustafa, Abdelmageed A, [Old Dominion Univ., Norfolk, VA (United States); Stutzman, Marcy L. [JLAB, Newport News, VA (United States); Adderley, Philip A. [JLAB, Newport News, VA (United States); Poelker, Matthew [JLAB, Newport News, VA (United States)

2014-03-01

The outgassing rates of four nominally identical 304L stainless steel vacuum chambers were measured to determine the effect of chamber coatings and heat treatments. One chamber was coated with titanium nitride (TiN) and one with amorphous silicon (a-Si) immediately following fabrication. One chamber remained uncoated throughout, and the last chamber was first tested without any coating, and then coated with a-Si following a series of heat treatments. The outgassing rate of each chamber was measured at room temperatures between 15 and 30 deg C following bakes at temperatures between 90 and 400 deg C. Measurements for bare steel showed a significant reduction in the outgassing rate by more than a factor of 20 after a 400 deg C heat treatment (3.5 x 10{sup 12} TorrL s{sup -1}cm{sup -2} prior to heat treatment, reduced to 1.7 x 10{ sup -13} TorrL s{sup -1}cm{sup -2} following heat treatment). The chambers that were coated with a-Si showed minimal change in outgassing rates with heat treatment, though an outgassing rate reduced by heat treatments prior to a-Si coating was successfully preserved throughout a series of bakes. The TiN coated chamber exhibited remarkably low outgassing rates, up to four orders of magnitude lower than the uncoated stainless steel. An evaluation of coating composition suggests the presence of elemental titanium which could provide pumping and lead to an artificially low outgassing rate. The outgassing results are discussed in terms of diffusion-limited versus recombination-limited processes.

Preliminary study on the forgeability and heat treatment response of niobium - containing tool steels materials

International Nuclear Information System (INIS)

Cescon, T.; Papaleo, R.

1981-01-01

The forgeability and microstructure of tool steels materials based on the M-2 composition, where W and V were partially replaced by Nb, were examined. The optimum heat-treating conditions were established. The poor response to heat treatment of some of the alloys studied indicated the need of increasing the C content of the steels when Nb is used as a substitute for W and V. (Author) [pt

Aesthetic value improvement of the ruby stone using heat treatment and its synergetic surface study

International Nuclear Information System (INIS)

Sahoo, Rakesh K.; Mohapatra, Birendra K.; Singh, Saroj K.; Mishra, Barada K.

2015-01-01

Highlights: • Natural ruby is heated at high temperature with metal oxide additives (PbO and ZnO) to enhance its aesthetic value. • Changes in surface characteristics of these natural rubies before and after heat treatment are compared. • The R-line peak splitting in the PL spectra and the contrary shift of the Al 2p peaks in the XPS spectra are explicated. - Abstract: The surface behavior of the natural ruby stones before and after heat treatment with metal oxide additives like: zinc oxide (ZnO) and lead oxide (PbO) have been studied. The surface appearance of the ruby stones processed with the metal oxides changed whereas the bulk densities of the stones remained within the range of 3.9–4.0 g/cm 3 . The cracks healing and pores filling by the metal oxides on the surface of the ruby have been examined using scanning electron microscopy. The chemical compositions based on the XPS survey scans are in good agreement with the expected composition. The phase and crystallinity of the ruby stones original and heat-treated were obtained from their X-ray diffraction patterns. The change in peak separation between R 1 and R 2 – peaks in photoluminescence spectra and the contrary binding energy shift of the Al 2p peaks in the X-ray photoelectron spectra have been explicated. Moreover, in this work we describe the change in surface chemical and physical characteristics of the ruby stone before and after heat treatment

Advances in the heat treatment of steels

International Nuclear Information System (INIS)

Morris, J.W. Jr.; Kim, J.I.; Syn, C.K.

1978-06-01

A number of important recent advances in the processing of steels have resulted from the sophisticated uses of heat treatment to tailor the microstructure of the steels so that desirable properties are established. These new heat treatments often involve the tempering or annealing of the steel to accompish a partial or complete reversion from martensite to austenite. The influence of these reversion heat treatments on the product microstructure and its properties may be systematically discussed in terms of the heat treating temperature in relation to the phase diagram. From this perspective, four characteristic heat treatments are defined: (1) normal tempering, (2) inter-critical tempering, (3) intercritical annealing, and (4) austenite reversion. The reactions occurring during each of these treatments are described and the nature and properties of typical product microstructures discussed, with specific reference to new commercial or laboratory steels having useful and exceptional properties

MATHEMATICAL MODELING OF HEATING RATE PRODUCT AT HIGH HEAT TREATMENT

Directory of Open Access Journals (Sweden)

M. M. Akhmedova

2014-01-01

Full Text Available Methods of computing and mathematical modeling are all widely used in the study of various heat exchange processes that provide the ability to study the dynamics of the processes, as well as to conduct a reasonable search for the optimal technological parameters of heat treatment.This work is devoted to the identification of correlations among the factors that have the greatest effect on the rate of heating of the product at hightemperature heat sterilization in a stream of hot air, which are chosen as the temperature difference (between the most and least warming up points and speed cans during heat sterilization.As a result of the experimental data warming of the central and peripheral layers compote of apples in a 3 liter pot at high-temperature heat treatment in a stream of hot air obtained by the regression equation in the form of a seconddegree polynomial, taking into account the effects of pair interaction of these parameters. 

Effect of cathode vibration and heat treatment on electromagnetic properties of flake-shaped diatomite coated with Ni–Fe alloy by electroplating

Energy Technology Data Exchange (ETDEWEB)

Lan, Mingming, E-mail: lan_mingming@163.com; Li, Huiqin; Huang, Weihua; Xu, Guangyin; Li, Yan

2015-03-01

In this paper, flake-shaped diatomite particles were used as forming templates for the fabrication of the ferromagnetic functional fillers by way of electroplating Ni–Fe alloy method. The effects of cathode vibration frequency on the content of Ni–Fe alloy in the coating and the surface morphologies of the coatings were evaluated. The electromagnetic properties of the coated diatomite particles before and after heat treatment were also investigated in detail. The results show that the core-shell flake-shaped diatomite particles with high content of Ni–Fe alloy and good surface qualities of the coatings can be obtained by adjusting cathode vibration frequency. The coated diatomite particles with heat treatment filled paraffin wax composites exhibit a superior microwave absorbing and electromagnetic properties compared to the non-heat treated samples. Additionally, the peaks of reflection loss are found to be able to shift to lower frequency by the heat treatment process, which indicates the heat treatment can adjust microwave absorbing frequency band. - Highlights: • We used the diatomite particles as template to fabricate the flake-shaped ferromagnetic fillers. • The diatomite particles were deposited pure magnetic Ni–Fe alloy by electroplating methods. • The coated diatomite particles were lightweight ferromagnetic fillers. • The composites containing coated diatomite particles with heat treatment exhibited great potential in the field of electromagnetic absorbing.

Effect of cathode vibration and heat treatment on electromagnetic properties of flake-shaped diatomite coated with Ni–Fe alloy by electroplating

International Nuclear Information System (INIS)

Lan, Mingming; Li, Huiqin; Huang, Weihua; Xu, Guangyin; Li, Yan

2015-01-01

In this paper, flake-shaped diatomite particles were used as forming templates for the fabrication of the ferromagnetic functional fillers by way of electroplating Ni–Fe alloy method. The effects of cathode vibration frequency on the content of Ni–Fe alloy in the coating and the surface morphologies of the coatings were evaluated. The electromagnetic properties of the coated diatomite particles before and after heat treatment were also investigated in detail. The results show that the core-shell flake-shaped diatomite particles with high content of Ni–Fe alloy and good surface qualities of the coatings can be obtained by adjusting cathode vibration frequency. The coated diatomite particles with heat treatment filled paraffin wax composites exhibit a superior microwave absorbing and electromagnetic properties compared to the non-heat treated samples. Additionally, the peaks of reflection loss are found to be able to shift to lower frequency by the heat treatment process, which indicates the heat treatment can adjust microwave absorbing frequency band. - Highlights: • We used the diatomite particles as template to fabricate the flake-shaped ferromagnetic fillers. • The diatomite particles were deposited pure magnetic Ni–Fe alloy by electroplating methods. • The coated diatomite particles were lightweight ferromagnetic fillers. • The composites containing coated diatomite particles with heat treatment exhibited great potential in the field of electromagnetic absorbing

29 CFR 1919.16 - Heat treatment.

Science.gov (United States)

2010-07-01

... 29 Labor 7 2010-07-01 2010-07-01 false Heat treatment. 1919.16 Section 1919.16 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) GEAR CERTIFICATION Certification of Vessels' Cargo Gear § 1919.16 Heat treatment. (a) All chains (other...

49 CFR 179.200-11 - Postweld heat treatment.

Science.gov (United States)

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Postweld heat treatment. 179.200-11 Section 179.200-11 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS... Postweld heat treatment. When specified in § 179.201-1, after welding is complete, postweld heat treatment...

Composite bulk Heat Insulation Made of loose Mineral and Organic Aggregate

Directory of Open Access Journals (Sweden)

Namsone Eva

2015-12-01

Full Text Available The task of building energy-efficiency is getting more important. Every house owner wishes to save up exploitation costs of heating, cooling, hot water production, ventilation, etc. and find cost-effective investments. One of the ways to reduce greenhouse gas emissions (GHGE is to minimize the heat transfer through the building by insulating it. Loose heat insulation is a good alternative to traditional board insulation, it is simple in use and cost-effective. Main drawback of this insulation is tendency to compact during exploitation. In the frame of this research composite loose heat insulation is elaborated, consisting on porous mineral foamed glass aggregate and local organic fiber materials (hemp and flaxen shives. Composite bulk insulation is an alternative solution which combines heat insulating properties and mechanical stability.

The Effect of Heat Treatment on the Thermo-Elastic Behavior of Ti Ni Shape Memory Alloy

International Nuclear Information System (INIS)

Ahmed, K.

2008-01-01

The Ti-Ni shape memory alloys are used in industrial, medical and biological applications because of their outstanding mechanical properties . Research work has been done to design a remote handling unit using such alloy to work in a high neutron irradiated areas .The pre-alloyed powder is supplied by Memory-Metalle GmbH with composition Ti-49.5 at % Ni. The Metal Injection Molding (MIM) technique has been used to fabricate the alloy and subsequent different heat treatments, spectroscopic and thermal analysis have been done to test the alloy performance. Regarding to this pre-alloyed powder composition, the thermo-elastic behavior is perfect. Transformation temperature in the range 27 degree C - 63 degree C has been achieved .The final sintering quality is not satisfactory. The results show that the proposed heat treatments are not able to release the generated internal stress

Technological and Thermal Properties of Thermoplastic Composites Filled with Heat-treated Alder Wood

Directory of Open Access Journals (Sweden)

Mürşit Tufan

2016-02-01

Full Text Available This study investigated the effect of heat-treated wood content on the water absorption, mechanical, and thermal properties of wood plastic composites (WPCs. The WPCs were produced from various loadings (30, 40, and 50 wt% of heat-treated and untreated alder wood flours (Alnus glutinosa L. using high-density polyethylene (HDPE with 3 wt% maleated polyethylene (MAPE coupling agent. All WPC formulations were compression molded into a hot press for 3 min at 170 ºC. The WPCs were evaluated using mechanical testing, Fourier transform infrared spectroscopy (FTIR, thermogravimetric analysis (TGA, and differential scanning calorimetry (DSC. The mechanical property values of the WPC specimens decreased with increasing amounts of the heat-treated wood flour, except for the tensile modulus values. The heat treatment of alder wood slightly increased the thermal stability of the WPCs compared with the reference WPCs. The crystallization degree (Xc and the enthalpy of crystallization of the WPCs slightly decreased with increasing content of the heat-treated wood flour. However, all WPCs containing the heat-treated alder wood flour showed a higher crystallinity degree than that of the virgin HDPE.

The effect of cold work, heat treatment, and composition on the austenite to R-phase transformation temperature of Ni-Ti shape memory alloys

International Nuclear Information System (INIS)

Thoma, P.E.; Angst, D.R.; Schachner, K.D.

1995-01-01

The influence of cold work (CW) and heat treatment (HT) on the austenite to R-Phase (A→R) transformation temperature (TT) of a near equiatomic and three other Ti rich NiTi SMA is examined. For the SMA having a near equiatomic composition, the A→R TT increases with increasing CW at low HT temperatures. For the SMA having the maximum possible Ti content, the A→R TT decreases with increasing CW at low HT temperatures. For all compositions, the A→R TT is not sensitive to CW at high HT temperatures. At a Ti content slightly below the maximum possible, the A→R TT is relatively insensitive to CW and HT temperature. For all of the SMA investigated, the A→R TT increases with increasing Ti content for a specific CW and HT temperature, and this effect is greatest at low CW and at high HT temperatures. (orig.)

Exploiting heat treatment effects on SMAs macro and microscopic properties in developing fire protection devices

Science.gov (United States)

Burlacu, L.; Cimpoeşu, N.; Bujoreanu, L. G.; Lohan, N. M.

2017-08-01

Ni-Ti shape memory alloys (SMAs) are intelligent alloys which demonstrate unique properties, such as shape memory effect, two-way shape memory effect, super-elasticity and vibration damping which, accompanied by good processability, excellent corrosion resistance and biocompatibility as well as fair wear resistance and cyclic stability, enabled the development of important industrial applications (such as sensors, actuators, fasteners, couplings and valves), medical applications (such as stents, bone implants, orthodontic archwires, minimal invasive surgical equipment) as well as environmental health and safety devices (anti-seismic dampers, fire safety devices). The phase transitions in Ni-Ti SMAs are strongly influenced by processing methods, chemical compositions and thermomechanical history. This paper presents a study of the effects of heat treatment on the mechanical and thermal properties of commercial Ni-Ti shape memory alloy (SMA). The experimental work involved subjecting a SMA rod to heat-treatment consisting in heating up to 500°C, 10 minutes-maintaining and water quenching. Mechanical properties were highlighted by microhardness tests while thermal characteristics were emphasized by differential scanning calorimetry (DSC). The presence of chemical composition fluctuations was checked by X-ray energy dispersive spectroscopy performed with an EDAX Bruker analyzer.

Improved process for the treatment of bituminous materials. [two heat treatments

Energy Technology Data Exchange (ETDEWEB)

1947-04-30

A continuous process for recovering valuable hydrocarbon oils from solid minerals adapted to produce such oils upon application of heat, consists of reducing the raw minerals to a powder, suspending the powdered minerals in a gaseous medium and subjecting the suspension thus formed to heat treatment in a primary reaction zone, followed by heat treatment in a secondary reaction zone separate from the primary reaction zone. The temperature during the second of said treatments being substantially higher than that of the first.

Influence of heat treatment on the wear life of hydraulic fracturing tools

Energy Technology Data Exchange (ETDEWEB)

Zheng, Chao; Liu, Yonghong; Wang, Hanxiang; Qin, Jie; Shen, Yang; Zhang, Shihong [China University of Petroleum, Qingdao (China)

2017-02-15

Wear phenomenon has caused severe damage or failure of fracturing tools in oil and gas industry. In this paper, influence of heat treatment on the mechanical properties and wear resistance of fracturing tool made of lamellar graphite grey cast iron were investigated. The surface composition and microstructure were characterized by X-ray diffraction (XRD) and metallographic microscope. Sliding wear tests were performed to study the tribological behavior. Tests results showed that wear rates of treated specimens decreased by 33 %. Besides, worn morphology and wear debris were analyzed using Scanning electron microscope (SEM) and Energy dispersive Xray spectra (EDS). Wear failure mechanisms of specimens were identified. Furthermore, on-site experiment results indicated that wear loss of treated samples decreased by 37.5 %. The wear life of hydraulic fracturing tools can be improved obviously by the heat treatment.

Influence of heat treatment on the wear life of hydraulic fracturing tools

International Nuclear Information System (INIS)

Zheng, Chao; Liu, Yonghong; Wang, Hanxiang; Qin, Jie; Shen, Yang; Zhang, Shihong

2017-01-01

Wear phenomenon has caused severe damage or failure of fracturing tools in oil and gas industry. In this paper, influence of heat treatment on the mechanical properties and wear resistance of fracturing tool made of lamellar graphite grey cast iron were investigated. The surface composition and microstructure were characterized by X-ray diffraction (XRD) and metallographic microscope. Sliding wear tests were performed to study the tribological behavior. Tests results showed that wear rates of treated specimens decreased by 33 %. Besides, worn morphology and wear debris were analyzed using Scanning electron microscope (SEM) and Energy dispersive Xray spectra (EDS). Wear failure mechanisms of specimens were identified. Furthermore, on-site experiment results indicated that wear loss of treated samples decreased by 37.5 %. The wear life of hydraulic fracturing tools can be improved obviously by the heat treatment

In-Situ Neutron Diffraction Under Tensile Loading of Powder-in-Tube Cu/Nb$_{3}$Sn Composite Wires Effect of Reaction Heat Treatment on Texture, Internal Stress State and Load Transfer

CERN Document Server

Scheuerlein, C; Thilly, L

2007-01-01

The strain induced degradation of Nb$_{3}$Sn superconductors can hamper the performance of high field magnets. We report elastic strain measurements in the different phases of entire non-heat treated and fully reacted Nb$_{3}$Sn composite strands as a function of uniaxial stress during in-situ deformation under neutron beam. After the reaction heat treatment the Cu matrix loses entirely its load carrying capability and the applied stress is transferred to the remaining Nb-Ta alloy and to the brittle (Nb-Ta)3Sn phase, which exhibits a preferential grain orientation parallel to the strand axis.

PROTECTIVE TREATMENT OF WOOD IMPREGNATING COMPOSITION OF PETROCHEMICAL WASTE

Directory of Open Access Journals (Sweden)

T. V. Maslakova

2015-01-01

Full Text Available The paper presents results of experimental and theoretical studies aimed at expanding the applications of the copolymers on the basis of the waste styrene production. One of the areas is used as impregnating compositions of wood materials, selection of optimal conditions modification on samples of the most widely used in the industry of wood, such as birch, aspen and other. Studies were conducted to obtain and use an impregnating compositions based on copolymers synthesized from waste products of styrene and the cubic remainder rectification of ethylbenzene (CRRE for the protective treatment of birch wood. Identified physic-chemical characteristics of physical mixtures of copolymers «CORS», «STAM», CRRE at different ratios. Studied the process of modification birch using the method of experiment planning greco-latin square of the fourth order, and the influence of such factors as the temperature of the impregnating composition, the duration of the impregnation, the temperature and duration of thermal treatment on the performance moisture resistance of wood. Were established optimal conditions modification birch wood treated impregnating compositions on the basis of physical mixtures of copolymer «CORS» with CRRE and copolymer «STAM» with CRRE is the mixing ratio 2:1, the duration and temperature of the impregnation 7 h and 95 0C, time and temperature of heat treatment 7 h and 170 0C, respectively. A sealing composition containing CRRE with copolymer «STAM» 1:2 is more preferable, as in the structure of the copolymer «STAM» contains carboxyl and anhydrite group. Thus was justified use for the modification of natural wood impregnating compositions on the basis of physical mixtures of CRRE with copolymers «CORS» and «STAM», which improve the properties of wood, increase moisture and weather resistance more than twice.

Study of the effects of heat-treatment of hydroxyapatite synthesized in gelatin matrix

Science.gov (United States)

Zaits, A. V.; Golovanova, O. A.; Kuimova, M. V.

2017-01-01

In the study, the isothermal thermogravimetric analysis (TGA) of hydroxyapatite synthesized in gelatin matrix (HAG) has been performed. 3 wt.% HAG samples were synthesized from the solution simulating the human extracellular fluid (SBF). X-ray diffraction and IR spectroscopy were used to determine the composition. During the experiment, increase in the calcination temperature up to 200°C-800°C was found to cause weight loss. The study of phase composition revealed that heat treatment does not affect the phase composition of the solid phase, which is composed of hydroxylapatite (HA). The prepared HAG (3 wt.% gelatin) samples are shown to have low thermal stability; the degradation of the samples occurs at 400°C.

Effect of heat-treatment on elevated temperature fatigue-crack growth behavior of two heats of Alloy 718

International Nuclear Information System (INIS)

Mills, W.J.; James, L.A.

1978-05-01

The room temperature and elevated temperature fatigue-crack growth behavior of two heats of Alloy 718 was characterized within a linear-elastic fracture mechanics framework. Two different heat-treatments were used: the ''conventional'' (ASTM A637) treatment, and a ''modified'' heat-treatment designed to improve the toughness of Alloy 718 base metal and weldments. Heat-to-heat variations in the fatigue-crack propagation behavior were observed in the conventionally-treated material. On the other hand, no heat-to-heat variations were observed in the modified condition. Furthermore, both heats of Alloy 718 exhibited superior fatigue-crack growth resistance when given the modified heat-treatment. Electron fractographic examination of Alloy 718 fatigue fracture surfaces revealed that the operative crack growth mechanisms were dependent on heat-treatment, temperature, and ΔK level

Cold storage condensation heat recovery system with a novel composite phase change material

International Nuclear Information System (INIS)

Xia, Mingzhu; Yuan, Yanping; Zhao, Xudong; Cao, Xiaoling; Tang, Zhonghua

2016-01-01

Highlights: • Cold storage condensation heat recovery system using PCM was proposed. • CW with a phase change temperature of nearly 80 °C was selected as the potential PCM. • The optimal mass ratio between the CW and EG was 10:1. • The thermal and physical performances of the CW/EG were investigated. • The thermal reliability was demonstrated by 1000 cycles. - Abstract: Using condensation heat from cold storage refrigeration systems to provide heat for domestic hot water preparation and industrial hot water supply promotes energy conservation. However, few studies have investigated cold storage condensation heat recovery using phase change materials (PCMs). In this study, a cold storage condensation heat recovery system that uses PCMs has been designed and analysed. According to the principle of energy cascade recycling, different operation modes could be effectively switched to recycle condensation heat. Furthermore, a novel and suitable phase change composite material is developed for cold storage condensation heat recovery, which has a relatively large latent heat, high thermal conductivity, and an appropriate phase change temperature (i.e. 80 °C). With carnauba wax (CW) as the PCM and expanded graphite (EG) as the additive, a composite was developed with an optimal mass ratio of CW:EG = 10:1. The thermal and physical properties and the interior structure of the composite were then investigated using a scanning electron microscope (SEM), thermal constants analyser (Hot Disk), differential scanning calorimeter (DSC), and Fourier transform infrared spectrometer (FT-IR). Furthermore, experiments on the melting and solidification processes and accelerated thermal cycling were also conducted. It was found that at the optimal mass ratio of 10:1, the temperatures of the CW/EG composite in the melting and solidification processes were 81.98 °C and 80.43 °C, respectively, while the corresponding latent heats were 150.9 J/g and 142.6 J/g, respectively

Influence of Ear Surface Area on Heat Tolerance of Composite ...

African Journals Online (AJOL)

Relative importance of ear surface area on heat tolerance of composite rabbit population was evaluated. The study was conducted during the dry and rainy seasons, climatic data were recorded to obtain categorical heat stress index. Physiological parameters, growth performance, ear length and ear width of the rabbits ...

Effect of Mixed Working Fluid Composition on Binary Cycle Condenser Heat Transfer Coefficients

Energy Technology Data Exchange (ETDEWEB)

Dan Wendt; Greg Mines

2011-10-01

Effect of Mixed Working Fluid Composition on Binary Cycle Condenser Heat Transfer Coefficients Dan Wendt, Greg Mines Idaho National Laboratory The use of mixed working fluids in binary power plants can provide significant increases in plant performance, provided the heat exchangers are designed to take advantage of these fluids non-isothermal phase changes. In the 1980's testing was conducted at DOE's Heat Cycle Research Facility (HCRF) where mixtures of different compositions were vaporized at supercritical pressures and then condensed. This testing had focused on using the data collected to verify that Heat Transfer Research Incorporated (HTRI) codes were suitable for the design of heat exchangers that could be used with mixtures. The HCRF data includes mixture compositions varying from 0% to 40% isopentane and condenser tube orientations of 15{sup o}, 60{sup o}, and 90{sup o} from horizontal. Testing was performed over a range of working fluid and cooling fluid conditions. Though the condenser used in this testing was water cooled, the working fluid condensation occurred on the tube-side of the heat exchanger. This tube-side condensation is analogous to that in an air-cooled condenser. Tube-side condensing heat transfer coefficient information gleaned from the HCRF testing is used in this study to assess the suitability of air-cooled condenser designs for use with mixtures. Results of an air-cooled binary plant process model performed with Aspen Plus indicate that that the optimal mixture composition (producing the maximum net power for the scenario considered) is within the range of compositions for which data exist. The HCRF data is used to assess the impact of composition, tube orientation, and process parameters on the condensing heat transfer coefficients. The sensitivity of the condensing coefficients to these factors is evaluated and the suitability of air-cooled condenser designs with mixtures is assessed. This paper summarizes the evaluation

Microwave heat treatment as a substitute for conventional treatment of palm oil fruits

International Nuclear Information System (INIS)

Mujahid H Al-Fayadh; Nor Azura Masabbir Ali

1996-01-01

Microwave energy has become a sound method of heat treatment because of its high penetration power, cleanliness and possible economic significance. In this research, microwave heat was used as a substitute for conventional blanching method of palm oil fruits. Microwave treatment at 2450 MHz and 800 watts gave very close color and frn,frying characteristics to oil of blanched fruits after one minute exposure time. However, five minutes of microwave heat gave severe husk oil discoloration after 49 hours of deep frying, compared to all oils extracted from fruits treated by either low, microwave exposure time or conventional steam treatment. Kernel oil, after five minutes of microwave treatment, was less discolored than both steam or microwave-treated fruits for one minute. More carotenes and discoloration compounds may be contributed to discoloration during microwave treatments. Oil chemical constants of both husk and kernel oils treated by microwave heat were close to those treated by conventional heat. Further research is needed to investigate detailed oil characteristics and evaluate the feasibility study for using microwave energy, as a substitute for conventional heat in palm oil industry

Production of AA2124/MoSi2/25p composites and effect of heat treatment on their microstructure, hardness and compression properties

Directory of Open Access Journals (Sweden)

Piyadeh, Fatemeh

2014-12-01

Full Text Available AA2124/25vol%MoSi2 composites were processed by two powder metallurgy routes: high energy ball milling of the reinforcement and alloy powder (B composite and wet blending with cyclohexane (W composite, both followed by extrusion to achieve full consolidation. As-extruded and heat treated composite bars were studied microstructurally and mechanically (hardness and compression tests under quasistatic loading. Microstructure and fracture profiles were observed by scanning electron microscopy and the reaction products formed in the matrix were identified by energy-dispersive X-ray spectroscopy and X-ray diffraction analysis. The results show that for both composites, the hardness of the specimens in solution and aged condition was higher than in the as-extruded condition. The hardness of the B composite was higher than that of the W composite whereas the age-hardenability of the B composite was significantly lower than that of the W composite. After heat treatments, small diffusion reaction phases appeared at the interface between matrix and reinforcements. Compressive yield strength and the ultimate strength of both composites improved considerably after the artificial ageing. The composite fracture surfaces exhibited microscopically a ductile appearance that consisted of dimples in the matrix and a fragile fracture of the MoSi2 particulates.En este trabajo se procesaron materiales compuestos AA2124/25vol% MoSi2 mediante dos rutas pulvimetalúrgicas: mezcla de refuerzo y matriz mediante molino de bolas de alta energía (compuesto B y mezcla húmeda con ciclohexano (compuesto W. Ambos polvos compuestos se consolidaron por extrusión. Los materiales recién extruidos y después de tratados térmicamente se estudiaron desde el punto de vista microestructural y mecánico (dureza y compresión bajo carga cuasiestática. Las microestructuras y los perfiles de fractura se observaron por microscopía electrónica de barrido y los productos de reacci

Synergistic effects of composition and heat treatment on microstructure and properties of vacuum die cast Al-Si-Mg-Mn alloys

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Jun-jie Xu

2018-03-01

Full Text Available The purpose of this study was to prepare high-quality Al-Si-Mg-Mn alloy with a good combination of strength and ductility employing the vacuum-assisted high-pressure die cast process. An orthogonal study of heat treatments was conducted to design an optimized T6 heat treatment process for both Al-10%Si-0.3%Mg-Mn and Al-11%Si-0.6%Mg-Mn alloys. The results demonstrate that no obvious blisters and warpage were observed in these two alloys with solid solution treatment. After the optimal T6 heat treatment of 530°C×3h + 165°C×6h, Al-11%Si-0.6%Mg-Mn alloy has better mechanical properties, of which tensile strength, yield strength and elongation reached 377.3 MPa, 307.8 MPa and 9%, respectively. The improvement of mechanical properties can be attributed to the high density of needle-like β″(Mg5Si6 precipitation after aging treatment and the fine and spherical eutectic Si particles uniformly distributed in the α-Al matrix.

THE INFLUENCE OF THE FILLER GRAIN COMPOSITION ON THE PROPERTIES OF THE HEAT-RESISTANT BASALTIC CONCRETE

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A. M. Gadzhiev

2017-01-01

Full Text Available Objectives. The optimal granulometric composition of filler compound ensures the production of concrete having improved  physical and mechanical characteristics, as well as minimal binder  consumption. The properties of heat-resistant concrete largely  depend on the type and the ratio of its components. Taking this into  account, the aim of the study is to determine the optimal grain composition of heat-resistant concrete.Methods. Methods for optimising the properties of heatresistant basaltic concrete with a composite binder and  mechanochemical activation of the filler grains were used during the  course of the research.A simplex-centroid experiment design is  applied for this purpose. The composite binder was subjected to  mechanochemical activation. Samples were made by vibration-pressing from a concrete mix with a cone draught of 2 cm.Results. The grain composition of heat-resistant concrete is proved  to be the most important variable factor, regulating which the  properties of concrete can be varied. The compositions of heat- resistant basaltic concrete with activated composite binder having a  maximum application temperature of 700 ºС are developed. The  influence of the grain composition of the basaltic filler on the  properties of basaltic concrete using mathematical experiment planning methods is determined. The regression equations for the ultimate tensile strength and bending stress of basaltic concrete are  obtained for heating temperature of 700ºC.Conclusion. The granulometric composition of heat-resistant basaltic concrete based on the activated binder is optimised for basic physical and technical properties. The optimal granulometric  design of the composition of heat-resistant concrete indicates that as the coarse fraction (particles greater than 0.63 mm in the filler  composition increases, the ultimate tensile strength and bending  stress of heatresistant basaltic concrete is increased

INFLUENCE ОF MODIFIER THERMAL TREATMENT ОN CHARACTERISTICS ОF COMPOSITE MATERIALS FOR PROTECTIVE COATINGS

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V. Ivashko

2012-01-01

Full Text Available This paper presents results that reveal influence of modifiers characterized by different nature and composition and subjected to heat treatment on operational characteristics of single and binary compositions. Interaction between dispersed clay particles and dependence of  coating properties on  their mass content in oligomeric and polymeric matrices have been justified in the paper. The paper contains data that prove an increase of coating hardness by 15–20 %. The coating composition includes thermally-treated dispersed clay particles.

Near field heat transfer between random composite materials. Applications and limitations

Energy Technology Data Exchange (ETDEWEB)

Santiago, Eva Yazmin; Esquivel-Sirvent, Raul [Univ. Nacional Autonoma de Mexico (Mexico). Inst. de Fisica

2017-05-01

We present a theoretical study of the limits and bounds of using effective medium approximations in the calculation of the near field radiative heat transfer between a composite system made of Au nanoparticles in a SiC host and an homogeneous SiC slab. The effective dielectric function of the composite slab is calculated using three different approximations: Maxwell-Garnett, Bruggeman, and Looyenga's. In addition, we considered an empirical fit to the effective dielectric function by Grundquist and Hunderi. We show that the calculated value of the heat flux in the near field is dependent on the model, and the difference in the effective dielectric function is larger around the plasmonic response of the Au nanoparticles. This, in turn, accounts for the difference in the near field radiative heat flux. For all values of filling fractions, the Looyenga approximation gives a lower bound for the heat flux.

Effect of cathode vibration and heat treatment on electromagnetic properties of flake-shaped diatomite coated with Ni-Fe alloy by electroplating

Science.gov (United States)

Lan, Mingming; Li, Huiqin; Huang, Weihua; Xu, Guangyin; Li, Yan

2015-03-01

In this paper, flake-shaped diatomite particles were used as forming templates for the fabrication of the ferromagnetic functional fillers by way of electroplating Ni-Fe alloy method. The effects of cathode vibration frequency on the content of Ni-Fe alloy in the coating and the surface morphologies of the coatings were evaluated. The electromagnetic properties of the coated diatomite particles before and after heat treatment were also investigated in detail. The results show that the core-shell flake-shaped diatomite particles with high content of Ni-Fe alloy and good surface qualities of the coatings can be obtained by adjusting cathode vibration frequency. The coated diatomite particles with heat treatment filled paraffin wax composites exhibit a superior microwave absorbing and electromagnetic properties compared to the non-heat treated samples. Additionally, the peaks of reflection loss are found to be able to shift to lower frequency by the heat treatment process, which indicates the heat treatment can adjust microwave absorbing frequency band.

Influence of the chemical composition, heat and surface treatment in the biofouling of austenitic stainless steels

International Nuclear Information System (INIS)

Sarro, M. I.; Aleman, O.; Moreno, D. A.; Roso, M.; Ranninger, C.

2004-01-01

The main objective of this study was to analyse the biofouling processes in the kinds of stainless steels used normally in industry (UNS S30400, UNS S30403 and UNS S31600), with different surface treatments after grinding and polishing. The study was developed using two microscopy techniques. Scanning Electron Microscopy (SEM was used to evaluate the microorganisms distribution in the materials, and Epi fluorescence Microscopy was used to evaluate the viability of cells in the biofilm. The results revealed the influence of the material, heat treatment, surface treatment and roughness in the biofouling processes in the stainless steel assays. (Author) 33 refs

Preparation and property investigation of multi-walled carbon nanotube (MWCNT/epoxy composite films as high-performance electric heating (resistive heating element

Directory of Open Access Journals (Sweden)

F. X. Wang

2018-04-01

Full Text Available A series of multi-walled carbon nanotube (MWCNT/epoxy composite films with a thickness of ~700 µm is prepared by a sequential process of premixing, post dispersing, film casting, and thermal curing. The effects of the physical shear dispersion on the properties of conductive polymer composites as the electric heating element are investigated. The scanning electron microscope (SEM images show that highly efficient conductive networks form with shear dispersions of MWCNTs in the polymer matrix. The electrical resistivity decreases sharply from ~1015 Ω·cm for the neat epoxy resin to ~102 Ω·cm for the composite film with 2.0 wt% MWCNTs in accordance with the percolation behaviour, and a low percolation threshold of ~0.018 wt% is fitted. The electric heating behaviour of the composite film is observed at a low MWCNT content of 0.05 wt% due to the high electrical conductivity. For the composite film with 2.0 wt% MWCNTs, an equilibrium temperature of 115 °C is reached at an applied voltage of 40 V within 30 s. The excellent electric heating behaviour, including the rapid temperature response, electric heating efficiency, and operational stability, is primarily related to the conductive two-dimensional networks consisting of MWCNTs and the thermodynamically stable polymer matrix.

An electrical-heating and self-sensing shape memory polymer composite incorporated with carbon fiber felt

International Nuclear Information System (INIS)

Gong, Xiaobo; Leng, Jinsong; Liu, Liwu; Liu, Yanju

2016-01-01

Shape memory polymers (SMPs) have the ability to adjust their stiffness, lock a temporary shape, and recover the permanent shape upon imposing an appropriate stimulus. They have found their way into the field of morphing structures. The electrically Joule resistive heating of the conductive composite can be a desirable stimulus to activate the shape memory effect of SMPs without external heating equipment. Electro-induced SMP composites incorporated with carbon fiber felt (CFF) were explored in this work. The CFF is an excellent conductive filler which can easily spread throughout the composite. It has a huge advantage in terms of low cost, simple manufacturing process, and uniform and tunable temperature distribution while heating. A continuous and compact conductive network made of carbon fibers and the overlap joints among them was observed from the microscopy images, and this network contributes to the high conductive properties of the CFF/SMP composites. The CFF/SMP composites can be electrical-heated rapidly and uniformly, and its’ shape recovery effect can be actuated by the electrical resistance Joule heating of the CFF without an external heater. The CFF/SMP composite get higher modulus and higher strength than the pure SMP without losing any strain recovery property. The high dependence of temperature and strain on the electrical resistance also make the composite a good self-sensing material. In general, the CFF/SMP composite shows great prospects as a potential material for the future morphing structures. (paper)

Heat treatment, microstructure and mechanical properties of a C–Mn–Al–P hot dip galvanizing TRIP steel

International Nuclear Information System (INIS)

Ding, Wei; Hedström, Peter; Li, Yan

2016-01-01

Heat treatments of a hot dip galvanizing TRIP (Transformation induced plasticity) steel with chemical composition 0.20C-1.50Mn-1.2Al-0.07P(mass%) were performed in a Gleeble 3500 laboratory equipment. The heat treatment process parameters were varied to investigate the effect of intercritical annealing temperature as well as isothermal bainitic transformation (IBT) temperature and time, on the microstructure and the mechanical properties. The microstructure was investigated using scanning electron microscopy, transmission electron microscopy and x-ray diffraction, while mechanical properties were evaluated by tensile testing. Furthermore, to generate a better understanding of the phase transformations during heat treatment, dilatometry trials were conducted. The desired microstructure containing ferrite, bainite, retained austenite and martensite was obtained after the heat treatments. It was further found that the IBT is critical in determining the mechanical properties of the steel, since it controls the fraction of bainite. With increasing bainite fraction, the fraction of retained austenite increases while the fraction of martensite decreases. The mechanical properties of the steel are excellent with a tensile strength above 780 MPa (expect in one case) and elongation above 22%.

Heat treatment, microstructure and mechanical properties of a C–Mn–Al–P hot dip galvanizing TRIP steel

Energy Technology Data Exchange (ETDEWEB)

Ding, Wei [School of Material and Metallurgy, Inner Mongolia University of Science and Technology, Baotou 014010 (China); Department of Materials Science and Engineering, KTH Royal Institute of Technology, SE-100 44 Stockholm (Sweden); Bayan Obo multimetallic resource comprehensive utilization Key lab, Inner Mongolia University of Science and Technology, Baotou 014010 (China); Hedström, Peter [Department of Materials Science and Engineering, KTH Royal Institute of Technology, SE-100 44 Stockholm (Sweden); Li, Yan [Department of Materials Science and Engineering, KTH Royal Institute of Technology, SE-100 44 Stockholm (Sweden); Bayan Obo multimetallic resource comprehensive utilization Key lab, Inner Mongolia University of Science and Technology, Baotou 014010 (China)

2016-09-30

Heat treatments of a hot dip galvanizing TRIP (Transformation induced plasticity) steel with chemical composition 0.20C-1.50Mn-1.2Al-0.07P(mass%) were performed in a Gleeble 3500 laboratory equipment. The heat treatment process parameters were varied to investigate the effect of intercritical annealing temperature as well as isothermal bainitic transformation (IBT) temperature and time, on the microstructure and the mechanical properties. The microstructure was investigated using scanning electron microscopy, transmission electron microscopy and x-ray diffraction, while mechanical properties were evaluated by tensile testing. Furthermore, to generate a better understanding of the phase transformations during heat treatment, dilatometry trials were conducted. The desired microstructure containing ferrite, bainite, retained austenite and martensite was obtained after the heat treatments. It was further found that the IBT is critical in determining the mechanical properties of the steel, since it controls the fraction of bainite. With increasing bainite fraction, the fraction of retained austenite increases while the fraction of martensite decreases. The mechanical properties of the steel are excellent with a tensile strength above 780 MPa (expect in one case) and elongation above 22%.

49 CFR 179.100-10 - Postweld heat treatment.

Science.gov (United States)

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Postweld heat treatment. 179.100-10 Section 179...-10 Postweld heat treatment. (a) After welding is complete, steel tanks and all attachments welded... treatment is prohibited. (c) Tank and welded attachments, fabricated from ASTM A 240/A 240M (IBR, see § 171...

Effect of thermal interface on heat flow in carbon nanofiber composites.

Science.gov (United States)

Gardea, F; Naraghi, M; Lagoudas, D

2014-01-22

The thermal transport process in carbon nanofiber (CNF)/epoxy composites is addressed through combined micromechanics and finite element modeling, guided by experiments. The heat exchange between CNF constituents and matrix is studied by explicitly accounting for interface thermal resistance between the CNFs and the epoxy matrix. The effects of nanofiber orientation and discontinuity on heat flow and thermal conductivity of nanocomposites are investigated through simulation of the laser flash experiment technique and Fourier's model of heat conduction. Our results indicate that when continuous CNFs are misoriented with respect to the average temperature gradient, the presence of interfacial resistance does not affect the thermal conductivity of the nanocomposites, as most of the heat flow will be through CNFs; however, interface thermal resistance can significantly alter the patterns of heat flow within the nanocomposite. It was found that very high interface resistance leads to heat entrapment at the interface near to the heat source, which can promote interface thermal degradation. The magnitude of heat entrapment, quantified via the peak transient temperature rise at the interface, in the case of high thermal resistance interfaces becomes an order of magnitude more intense as compared to the case of low thermal resistance interfaces. Moreover, high interface thermal resistance in the case of discontinuous fibers leads to a nearly complete thermal isolation of the fibers from the matrix, which will marginalize the contribution of the CNF thermal conductivity to the heat transfer in the composite.

Influence of heat treatment on the high temperature oxidation mechanisms of an Fe-TiCN cermet

OpenAIRE

Alvaredo Olmos, Paula; Abajo Clemente, Carolina; Tsipas, Sophia Alexandra; Gordo Odériz, Elena

2014-01-01

In this study, the oxidation behaviour of an iron matrix cermet containing 50 % vol. Ti(C,N) was investigated before and after heat treatment by oxidation tests performed in static air at temperatures between 500 °C and 1000 °C. The oxidation mechanism for this type of composite materials was established and it was found that the heat treated material presents lower mass gain than the as-sintered material at the early stages of the oxidation, due to the volatilization of oxides. The oxidation...

Formation of microstructure and properties on hot working and heat treatment of high strength modular cast iron

International Nuclear Information System (INIS)

Trajno, A.I.; Yusupov, V.S.; Kugushin, A.A.

1999-01-01

The possibility of plastic deformation of high strength modular cast iron (HSNCI) is under study. The microstructure and mechanical properties of hot worked and heat treated cast iron are investigated for the composition, %: Fe - 2.9 C - 2.4 Si - 0.7 Ni - 0.05 Mg - 0.04 Ce. It is stated that HSNCI can withstand various types of hot working without fracturing. Graphite inclusions lose their modular shape irreversibly during plastic deformation. Subsequent heat treatment affects the metal matrix only. The heating in oxidizing environment is noted to result in cast iron surface decarbonization [ru

Heating on the volatile composition and sensory aspects of extra-virgin olive oil

Directory of Open Access Journals (Sweden)

Cleiton Antônio Nunes

2013-12-01

Full Text Available The main ways by which extra-virgin olive oil is consumed include direct application on salads or as an ingredient in sauces, but it is also been used by some for cooking, including frying and baking. However, it has been reported that under heat stress, some nonglyceridic components of olive oil are degraded. So, the effect of heating (at 50, 100, 150, and 200 °C for 2 h on the volatile composition and sensory aspects of extra-virgin olive oil were evaluated. Heating altered the volatile composition of extra-virgin olive oil, mainly at higher temperatures (above 150 °C. The main modifications were related to the formation of large amounts of oxidized compounds, particularly large chain aldehydes. Sensory aspects were also altered when the oil was heated to higher temperatures, which might have occurred because of color alterations and mainly changes in the volatile composition of the oil.

Effect of pre-cooling and heat treatment on antioxidant enzymes ...

African Journals Online (AJOL)

Effect of pre-cooling and heat treatment on antioxidant enzymes profile of mango and banana. ... In banana, pre-cooling treatment (8 ºC) and heat treatment followed by cooling reduced CAT activity in peel and pulp, whereas POX activity increased. Pre-cooling and heat treatments altered normal homeostasis of these fruits, ...

Heat treatment control of Bi-2212 coils: I. Unravelling the complex dependence of the critical current density of Bi-2212 wires on heat treatment

Science.gov (United States)

Shen, Tengming; Li, Pei; Ye, Liyang

2018-01-01

A robust and reliable heat treatment is crucial for developing superconducting magnets from several superconductors especially Bi-2212. An improper heat treatment may significantly reduce the critical current density Jc of a Bi-2212 superconducting coil, even to zero, since the Jc of Bi-2212 wires is sensitive to parameters of its heat treatment (partial melt processing). To provide an essential database for heat treating Bi-2212 coils, the dependence of Jc on heat treatment is studied systematically in 11 industrial Bi-2212 wires, revealing several common traits shared between these wires and outlier behaviors. The dependence of the Jc of Bi-2212 on heat treatment is rather complex, with many processing parameters affecting Jc, including the peak processing temperature Tp, the time at the peak temperature tp, the time in the melt tmelt, the rate at which Bi-2212 melt is initially cooled CR1, the rate at which the solidification of Bi-2212 melt occurs CR2, and the temperature Tq at which the cooling rate switches from CR1 to CR2. The role of these parameters is analyzed and clarified, in the perspective of heat treating a coil. Practical advices on heat treatment design are given. The ability of a Bi-2212 coil to follow the prescribed recipe decreases with increasing coil sizes. The size of a coil that can be properly heat treated is determined.

Changes occurring in vegetable oils composition due to microwave heating

Directory of Open Access Journals (Sweden)

Hassan El-Mallah, M.

2003-12-01

Full Text Available The effect of microwave heating on three vegetable oils having different lipid compositions was studied. Sunflower, soybean and peanut oils in comparison with oil admixture of soybean and peanut oil (1:1, w/w, were selected for this study. Each oil was heated for 2, 4, 6, 8, 10, 12, 15 and 18 minutes in microwave oven. Peroxide value, free acidity and colour absorbance (at 420 nm were proportionally increasing with the increase of heating period. Colour absorption threw light on the formation of browning products arising from phospholipids during microwave heating. Total tocopherol contents were determined by preparative thin layer chromatography, whereas the fatty acid compositions and formed epoxy acid were analyzed by capillary gas liquid chromatography. The formed conjugated dienes and trienes were determined by UV spectrophotometry. It was found that the total tocopherols of the microwave heated oils, decreased depending on the type of the predominating tocopherols. Also a relation of peroxide formation, during microwave heating, with changes in total tocopherol composition was discussed. It was found that polyunsaturated fatty acids generally decreased by increasing the heating period. The results obtained from the heated oil admixture helped interpret the results obtained from other heated individual oils.Se estudia el efecto del calentamiento en horno de microondas sobre aceites de diferente composición en ácidos grasos. Aceites de girasol, soja, cacahuete y una mezcla de soja y cacahuete al 50%, se calentaron durante 2, 4, 6, 8 10, 12, 15 y 18 minutos. Los valores de índice de peróxidos, acidez libre y absorbancia a 420 nm fueron proporcionales al tiempo de calentamiento. Otras determinaciones incluyeron el contenido total en tocoferoles mediante cromatografía en capa fina, la composición en ácidos grasos y en epoxiácidos mediante cromatografía gas líquido, y la formación de dienos y trienos conjugados mediante

Lowcost automated control for steel heat treatments

International Nuclear Information System (INIS)

Zambaldi, Edimilson; Magalhães, Ricardo R.; Barbosa, Bruno H.G.; Silva, Sandro P. da; Ferreira, Danton D.

2017-01-01

Highlights: • Control the furnace temperature measured by thermocouple and adjusts it. • Activating the furnace resistors through Pulse Width Modulation. • Appling heat treatments to steels by a low-cost controller. - Abstract: The aim of this paper is to propose a low cost, automated furnace control system for the heat treatment of steel. We used an open source electronic prototyping platform to control the furnace temperature, thus reducing human interaction during the heat process. The platform can be adapted to non-controlled commercial furnaces, which are often used by small businesses. A Proportional-Integral-Derivative (PID) controller was implemented to regulate the furnace temperature based on a defined heat treatment cycle. The embedded system activates the furnace resistors through Pulse Width Modulation (PWM), allowing for control of electrical power supplied to the furnace. Hardening and tempering were performed on standard steel samples using a traditional method (visual inspection without temperature control) as well the embedded system with PID feedback control. The results show that the proposed system can reproduce an arbitrary heat treatment curve with accuracy and provide the desired final hardness as inferred through metallographic analysis. In addition, we observed a 6% saving in energy consumption using the proposed control system. Furthermore, the estimated cost to implement the system is 42% lower than a commercial controller model implemented in commercial furnaces.

Mortality of insect life stages during simulated heat treatment

Science.gov (United States)

. Heat treatment for insect disinfestation uses elevated air temperatures that are lethal to stored-product insects. Heat treatment has been demonstrated in our research to offer a reduced-risk alternative to fumigation or residual pesticide use in empty bins. Heat is also compatible with organic gr...

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

Science.gov (United States)

Zappa, Sebastián; Svoboda, Hernán; Surian, Estela

2017-02-01

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

Heat Treatment of Tools in Light Industry

Science.gov (United States)

Petukhov, V. A.

2005-09-01

Heat treatment processes for some tools (knitting needles, travelers for thimbles of spinning and doubling frames, thread-forming spinnerets) used for the production of cloths, hosiery, and other articles) in the knitting and textile industries are considered. Problems of the choice of steel and the kind and parameters of heat treatment are discussed in connection with the special features of tool design and operating conditions.

Effect of high temperature heat treatments on the quality factor of a large-grain superconducting radio-frequency niobium cavity

Science.gov (United States)

Dhakal, P.; Ciovati, G.; Myneni, G. R.; Gray, K. E.; Groll, N.; Maheshwari, P.; McRae, D. M.; Pike, R.; Proslier, T.; Stevie, F.; Walsh, R. P.; Yang, Q.; Zasadzinzki, J.

2013-04-01

Large-grain Nb has become a viable alternative to fine-grain Nb for the fabrication of superconducting radio-frequency cavities. In this contribution we report the results from a heat treatment study of a large-grain 1.5 GHz single-cell cavity made of “medium purity” Nb. The baseline surface preparation prior to heat treatment consisted of standard buffered chemical polishing. The heat treatment in the range 800-1400°C was done in a newly designed vacuum induction furnace. Q0 values of the order of 2×1010 at 2.0 K and peak surface magnetic field (Bp) of 90 mT were achieved reproducibly. A Q0 value of (5±1)×1010 at 2.0 K and Bp=90mT was obtained after heat treatment at 1400°C. This is the highest value ever reported at this temperature, frequency, and field. Samples heat treated with the cavity at 1400°C were analyzed by secondary ion mass spectrometry, x-ray photoelectron spectroscopy, energy dispersive x ray, point-contact tunneling, and x-ray diffraction, and revealed a complex surface composition which includes titanium oxide, increased carbon, and nitrogen content but reduced hydrogen concentration compared to a non-heat-treated sample.

A study on the effect of solution heat treatment on the corrosion resistance of super duplex stainless steels

International Nuclear Information System (INIS)

Park, Jee Yong; Park, Yong Soo; Kim, Soon Tae

2001-01-01

High temperature solution heat treatment(typically higher than 1100 .deg. C) is known generally to reduces the resistance to localized corrosion on super duplex stainless. This is attributed to the formation of zone depleted of alloying elements. In this study, the corrosion properties were investigated on super duplex stainless steels with various solution heat treatments. The corrosion resistance of these steels was evaluated in terms of critical pitting temperature and cyclic potentiodynamic polarization test. Chemical composition of the austenite and ferrite phases were analyzed by SEM-EDS. The following results were obtained. (1) By conducting furnace cooling, critical pitting temperature and repassivation potential increased. (2) By omitting furnace cooling, solution heat treatment produced Cr and Mo depleted zone in the phase boundary. (3) During furnace cooling, Cr and Mo rediffused through the phase boundary. This increased the corrosion resistance of super duplex stainless steels

Copper matrix composites as heat sink materials for water-cooled divertor target

Directory of Open Access Journals (Sweden)

Jeong-Ha You

2015-12-01

Full Text Available According to the recent high heat flux (HHF qualification tests of ITER divertor target mock-ups and the preliminary design studies of DEMO divertor target, the performance of CuCrZr alloy, the baseline heat sink material for DEMO divertor, seems to only marginally cover the envisaged operation regime. The structural integrity of the CuCrZr heat sink was shown to be affected by plastic fatigue at 20 MW/m². The relatively high neutron irradiation dose expected for the DEMO divertor target is another serious concern, as it would cause significant embrittlement below 250 °C or irradiation creep above 350 °C. Hence, an advanced design concept of the divertor target needs to be devised for DEMO in order to enhance the HHF performance so that the structural design criteria are fulfilled for full operation scenarios including slow transients. The biggest potential lies in copper-matrix composite materials for the heat sink. In this article, three promising Cu-matrix composite materials are reviewed in terms of thermal, mechanical and HHF performance as structural heat sink materials. The considered candidates are W particle-reinforced, W wire-reinforced and SiC fiber-reinforced Cu matrix composites. The comprehensive results of recent studies on fabrication technology, design concepts, materials properties and the HHF performance of mock-ups are presented. Limitations and challenges are discussed.

49 CFR 179.300-10 - Postweld heat treatment.

Science.gov (United States)

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Postweld heat treatment. 179.300-10 Section 179.300-10 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS... Postweld heat treatment. After welding is complete, steel tanks and all attachments welded thereto, must be...

7 CFR 58.236 - Pasteurization and heat treatment.

Science.gov (United States)

2010-01-01

... 7 Agriculture 3 2010-01-01 2010-01-01 false Pasteurization and heat treatment. 58.236 Section 58... Service 1 Operations and Operating Procedures § 58.236 Pasteurization and heat treatment. All milk and... is handled according to sanitary conditions approved by the Administrator. (a) Pasteurization. (1...

Dry sliding wear behavior of heat treated hybrid metal matrix composite using Taguchi techniques

International Nuclear Information System (INIS)

Kiran, T.S.; Prasanna Kumar, M.; Basavarajappa, S.; Viswanatha, B.M.

2014-01-01

Highlights: • ZA-27 alloy is used as matrix material and reinforced with SiC and Gr particles. • Heat treatment was carried out for all specimen. • Dry sliding wear test was done on pin-on-disc apparatus by Taguchi technique. • ZA-27/9SiC–3Gr showed superior wear resistance over the base alloy. • Ceramic mixed mechanical layer on contact surface of composite was formed. - Abstract: Dry sliding wear behavior of zinc based alloy and composite reinforced with SiCp (9 wt%) and Gr (3 wt%) fabricated by stir casting method was investigated. Heat treatment (HT) and aging of the specimen were carried out, followed by water quenching. Wear behavior was evaluated using pin on disc apparatus. Taguchi technique was used to estimate the parameters affecting the wear significantly. The effect of HT was that it reduced the microcracks, residual stresses and improved the distribution of microconstituents. The influence of various parameters like applied load, sliding speed and sliding distance on wear behavior was investigated by means and analysis of variance (ANOVA). Further, correlation between the parameters was determined by multiple linear regression equation for each response. It was observed that the applied load significantly influenced the wear volume loss (WVL), followed by sliding speed implying that increase in either applied load or sliding speed increases the WVL. Whereas for composites, sliding distance showed a negative influence on wear indicating that increase in sliding distance reduces WVL due to the presence of reinforcements. The wear mechanism of the worn out specimen was analyzed using scanning electron microscopy. The analysis shows that the formation and retention of ceramic mixed mechanical layer (CMML) plays a major role in the dry sliding wear resistance

Failures of tool steels after heat treatments

International Nuclear Information System (INIS)

Nunez-Gonzalez, G.

1990-01-01

The main objective of the work was to determine the most common defects occuring in tool steels of the AISI D-2, S-1, 0-1 and W-2 series during thermal treatment. Defects were evaluated by metallographic analyses, a method used to determine and recognize micro structural defects and their origin in order to be able to eliminate and correct some of the stages that are caused by heat treatment. Results show a large number of defects due to irregularities during thermal heating such as excess or lack of temperature, heating time, and atmosphere, rectifying and handling in service and, to a lesser extent, poor design. In conclusion, with the results obtained for each of the thermal treatments it is necessary to define, particularly the values each of these variables should have since they affect the material properties. (Author)

Manufacturing of kevlar/polyester composite by resin transfer moulding using conventional and microwave heating

International Nuclear Information System (INIS)

Abdullah, I.

2015-01-01

Microwave heating was incorporated into the resin transfer moulding technique. Polytetrafluoroethylene (PTFE) mould was used to cure the composite panel. Through the use of microwave heating, the mechanical and physical properties of produced Kevlar fibre/polyester composites were compared to those manufactured by conventional resin transfer moulding. The flexural modulus and flexural strength of 6-ply conventionally cured composites was 45% and 9% higher than the flexural modulus and flexural strength of 6-ply microwaved cured composites, respectively. However, 19% increase in interlaminar shear strength (ILSS) and 2% increase in compressive strength was observed in 6-ply microwave cured composites. This enhancement in ILSS and compressive strength is attributed to the better interfacial bonding of polyester resin with Kevlar fibres in microwaved cured composite, which was also confirmed via electron microscopy scanning. Furthermore, the microwave cured composite yielded maximum void contents (3%). (author)

Effects of thermal and enzymatic treatments and harvesting time on the microbial quality and chemical composition of fibre hemp (Cannabis sativa L.)

DEFF Research Database (Denmark)

Nykter, M.; Kymalainen, H.R.; Thomsen, Anne Belinda

2008-01-01

The aim of the present study was to examine the effects of pectinase enzyme treatment followed by thermal treatments (steam explosion and dry heating) on the microbial quality and chemical composition of hemp fibres. Before these treatments, the fibres were separated manually from the stems...... materials. Dry heating had no effect on mould and bacterial counts at temperatures below 120 degrees C and durations less than 60 min. The chemical composition was affected by the enzymatic treatment due to extraction and degradation of water-soluble components, pectin and ash. Thus the cellulose content...... increased by 6% w/w to 67-70% w/w. Steam explosion of the untreated hemp fibres increased the cellulose content to 74% w/w, whereas steam explosion of enzymatically treated hemp increased the cellulose content to 78% w/w. (c) 2007 Elsevier Ltd. All rights reserved....

Using geothermal energy to heat a portion of a formation for an in situ heat treatment process

Science.gov (United States)

Pieterson, Roelof; Boyles, Joseph Michael; Diebold, Peter Ulrich

2010-06-08

Methods of using geothermal energy to treat subsurface formations are described herein. Methods for using geothermal energy to treat a subsurface treatment area containing or proximate to hydrocarbons may include producing geothermally heated fluid from at least one subsurface region. Heat from at least a portion of the geothermally heated fluid may be transferred to the subsurface treatment area to heat the subsurface treatment area. At least some hydrocarbon fluids may be produced from the formation.

Propagation of internal stresses in composite materials during heating and cooling according to thermal cycles of welding

International Nuclear Information System (INIS)

Gukasyan, L.E.; Belov, V.V.

1977-01-01

Investigations of free thermal expansion of a composite material, of fibre and matrix during welding thermal cycle make it possible to estimate mean internal strain and stress in the composite components, as well as the residual internal stress and strain present in the composite material after manufacturing. The samples investigated consisted of nickel-chromium EhI445 alloy, reinforced by tungsten-rhenium alloy fibres. As the composite material was cooled and heated in course of welding, the stress and strain changed their sign twice, the first time upon heating, the second time upon cooling. After complete cooling of the composite material residual stresses in the fibre stay at the proportionality level, while those in the matrix are lower. Experimental evidence of internal stress and strain appearing in the composite material during heating are fairly consistent with calculations in the elastic region, if account is taken of the temperature of internal residual stress relaxation upon heating

Examination of heat treatments at preservation of grape must

Directory of Open Access Journals (Sweden)

Péter Korzenszky

2014-02-01

Full Text Available Heat treatment is a well-known process in food preservation. It is made to avoid and to slow down food deterioration. The process was developed by Louise Pasteur French scientist to avoid late among others wine further fermentation. The different heat treatments influence the shelf life in food production. In our article we present the process of grape must fermentation, as grape must is the base material of wine production. The treatment of harvested fresh grape juice has a big influence on end product quality. It is our experiments we examined the same grape must with four different methods in closed and in open spaces to determine CO2 concentration change. There are four different methods for treatment of grape juice: boiling, microwave treatment, treatment by water bath thermostat and a control without treatment. As a result of the comparison it can be stated that the heat treatment delays the start of fermentation, thereby increasing shelf life of grape must. However, no significant differences were found between two fermentation of heat-treated grape must by the microwave and water-bath thermostat. The different heat treatment of grape must base materials was done at the laboratory in Faculty of Mechanical Engineering of Szent István University. The origin of the table grapes used for the examination was Gödöllő-hillside. Normal 0 21 false false false HU X-NONE X-NONE

Effect of heat treatment on the corrosion behaviour of Al-Zn alloys in seawater

International Nuclear Information System (INIS)

Siti Radiah Mohd Kamarudin; Muhamad Daud; Nur Ubaidah Saidin; Zaifol Samsu

2010-01-01

A study has been carried out to investigate the effect of heat treatment on the corrosion behaviour of Al-Zn alloys in seawater environment. The microstructure, potential and current capacity of the samples were studied. Open circuit potential (OCP) of 96 hours was measured against saturated calomel electrode (SCE) and estimating current capacity of the alloys were calculated by using protective current generated from the capacity test. For the microstructure study, optical microscope is used to examine the surface morphology before and after test. The results show that the heat treated samples of 2 hours at 550 degree Celsius and variation in alloys composition affected the values of alloys OCP, current capacity and microstructure. (author)

Effect of heat treatment on carbon steel pipe welds

International Nuclear Information System (INIS)

Mohamad Harun.

1987-01-01

The heat treatment to improve the altered properties of carbon steel pipe welds is described. Pipe critical components in oil, gasification and nuclear reactor plants require adequate room temperature toughness and high strength at both room and moderately elevated temperatures. Microstructure and microhardness across the welds were changed markedly by the welding process and heat treatment. The presentation of hardness fluctuation in the welds can produce premature failure. A number of heat treatments are suggested to improve the properties of the welds. (author) 8 figs., 5 refs

Effect of high temperature heat treatments on the quality factor of a large-grain superconducting radio-frequency niobium cavity

Directory of Open Access Journals (Sweden)

P. Dhakal

2013-04-01

Full Text Available Large-grain Nb has become a viable alternative to fine-grain Nb for the fabrication of superconducting radio-frequency cavities. In this contribution we report the results from a heat treatment study of a large-grain 1.5 GHz single-cell cavity made of “medium purity” Nb. The baseline surface preparation prior to heat treatment consisted of standard buffered chemical polishing. The heat treatment in the range 800–1400°C was done in a newly designed vacuum induction furnace. Q_{0} values of the order of 2×10^{10} at 2.0 K and peak surface magnetic field (B_{p} of 90 mT were achieved reproducibly. A Q_{0} value of (5±1×10^{10} at 2.0 K and B_{p}=90  mT was obtained after heat treatment at 1400°C. This is the highest value ever reported at this temperature, frequency, and field. Samples heat treated with the cavity at 1400°C were analyzed by secondary ion mass spectrometry, x-ray photoelectron spectroscopy, energy dispersive x ray, point-contact tunneling, and x-ray diffraction, and revealed a complex surface composition which includes titanium oxide, increased carbon, and nitrogen content but reduced hydrogen concentration compared to a non-heat-treated sample.

Effect of high temperature heat treatments on the quality factor of a large-grain superconducting radio-frequency niobium cavity

Energy Technology Data Exchange (ETDEWEB)

Dhakal, P.; Ciovati, G.; Myneni, G. R.; Gray, K. E.; Groll, N.; Maheshwari, P.; McRae, D. M.; Pike, R.; Proslier, T.; Stevie, F.; Walsh, R. P.; Yang, Q.; Zasadzinzki, J.

2013-04-01

Large-grain Nb has become a viable alternative to fine-grain Nb for the fabrication of superconducting radio-frequency cavities. In this contribution we report the results from a heat treatment study of a large-grain 1.5 GHz single-cell cavity made of “medium purity” Nb. The baseline surface preparation prior to heat treatment consisted of standard buffered chemical polishing. The heat treatment in the range 800–1400°C was done in a newly designed vacuum induction furnace. Q{sub 0} values of the order of 2×10{sup 10} at 2.0 K and peak surface magnetic field (B{sub p}) of 90 mT were achieved reproducibly. A Q{sub 0} value of (5±1)×10{sup 10} at 2.0 K and B{sub p}=90mT was obtained after heat treatment at 1400°C. This is the highest value ever reported at this temperature, frequency, and field. Samples heat treated with the cavity at 1400°C were analyzed by secondary ion mass spectrometry, x-ray photoelectron spectroscopy, energy dispersive x ray, point-contact tunneling, and x-ray diffraction, and revealed a complex surface composition which includes titanium oxide, increased carbon, and nitrogen content but reduced hydrogen concentration compared to a non-heat-treated sample.

Effect of Different Heat Treatment Temperatures on the Chemical Composition and Structure of Chinese Fir Wood

Directory of Open Access Journals (Sweden)

Shichao Cheng

2016-03-01

Full Text Available The properties of wood can be improved after heat-treatment. There have been many studies dealing with mechanical properties and chemical modifications of heat-treated wood. The purpose of this paper is to provide a new analysis method, to give better insights on the hemicelluloses, cellulose, and lignin contents of heat-treated wood by using Fourier transform infrared (FT-IR and two-dimensional infrared (2D-IR spectroscopies. The FT-IR spectra results showed progressive degradation in the carbonyl groups of the glucuronic acid units and degradation of the pyranose of hemicelluloses. These changes were measured as the percentage decrease of crystalline cellulose and the loss of C=O and C=C groups linking together the aromatic skeleton of lignin. The 2D-IR spectra showed the appearance of 5 × 5 peak clusters in the 1000 to 1200 cm-1 region, which could account for the hemicellulose degradation. In addition, changes in the degree of sensitivity at 1627 and 1509 cm-1 coincided with cross-linking reactions among the aromatic units in the lignin molecules.

Social vulnerability to heat in Greater Atlanta, USA: spatial pattern of heat, NDVI, socioeconomics and household composition

Science.gov (United States)

Sim, Sunhui

2017-10-01

The purpose of the article is evaluating spatial patterns of social vulnerability to heat in Greater Atlanta in 2015. The social vulnerability to heat is an index of socioeconomic status, household composition, land surface temperature and normalized differential vegetation index (NDVI). Land surface temperature and NDVI were derived from the red, NIR and thermal infrared (TIR) of a Landsat OLI/TIRS images collected on September 14, 2015. The research focus is on the variation of heat vulnerability in Greater Atlanta. The study found that heat vulnerability is highly clustered spatially, resulting in "hot spots" and "cool spots". The results show significant health disparities. The hotspots of social vulnerability to heat occurred in neighborhoods with lower socioeconomic status as measured by low education, low income and more poverty, greater proportion of elderly people and young children. The findings of this study are important for identifying clusters of heat vulnerability and the relationships with social factors. These significant results provide a basis for heat intervention services.

Investigation of effects of boron additives and heat treatment on carbides and phase transition of highly alloyed duplex cast iron

International Nuclear Information System (INIS)

Tasgin, Yahya; Kaplan, Mehmet; Yaz, Mehmet

2009-01-01

The effect of boron additives and heat treatment on the microstructural morphology of the transition zone in a duplex cast iron, which has an outer shell of white cast iron (with a high Cr-content and containing boron additives) and an inner side composed of normal gray cast iron, has been investigated. For this purpose, two experimental materials possessing different compositions of white-gray duplex cast iron were produced. Subsequently, metallographic investigations were carried out to study the effect of heat treatment applied to the experimental materials by using the scanning electron microscopy technique, along with optical microscopy and energy dispersive X-ray spectroscopy. Moreover, the formation of various phases and carbide composites in the samples and their effects on the hardness were also investigated using X-ray diffraction techniques. The results of investigations, and hardness showed that addition of the elements Cr and B to high-alloyed white cast iron affected carbide formation significantly, while simultaneously hardening the microstructure, and consequently the carbide present in the transition area of white-gray cast iron was spread out and became thinner. However, B additives and heat treatment did not cause any damage to the transition region of high Cr-content duplex cast iron.

PECULIARITIES OF GENERALIZATION OF SIMILAR PHENOMENA IN THE PROCESS OF FISH HEAT TREATMENT

Directory of Open Access Journals (Sweden)

V. A. Pokhol’chenko

2015-01-01

Full Text Available The theoretical presuppositions for the possibility of generalizing and similarity founding in dehydration and wet materials heating processes are studieded in this article. It is offered to carry out the given processes generalization by using dimensionless numbers of similarity. At the detailed analyzing of regularities of heat treatment processes of fish in different modes a significant amount of experienced material was successfully generalized on the basis of dimensionless simplex (similarity numbers. Using the dimensionless simplex allowed to detect a number of simple mathematical models for the studied phenomena. The generalized kinetic models of fish dehydration, the generalized dynamic models (changing moisture diffusion coefficients, the generalized kinetic models of fish heating (the temperature field changing in the products thickness, average volume and center were founded. These generalized mathematical models showed also relationship of dehydration and heating at the processes of fish semi-hot, hot smoking (drying and frying. The relationship of the results from the physical nature of the dehydration process, including a change in the binding energy of the moisture with the material to the extent of the process and the shrinkage impact on the rate of the product moisture removal is given in the article. The factors influencing the internal structure and properties of the raw material changing and retarding the dehydration processes are described there. There was a heating rate dependence of fish products on the chemical composition the geometric dimensions of the object of heating and on the coolant regime parameters. A unique opportunity is opened by using the generalized models, combined with empirically derived equations and the technique of engineering calculation of these processes, to design a rational modes of heat treatment of raw materials and to optimize the performance of thermal equipment.

Thermoluminescent determination of prehistoric heat treatment of chert artifacts

International Nuclear Information System (INIS)

Melcher, C.L.; Zimmerman, D.W.

1977-01-01

In recent years archeologists have become interested in the extent to which prehistoric peoples heat-treated chert prior to shaping it into tools. Thermoluminescent determination of the radiation dose accumulated by an artifact since it was formed or last heated provides a simple, reliable test for such heat treatment. This test can be applied to single artifacts without the need for raw source material for comparison. Results on 25 artifacts from four sites indicate that, for many chert sources, color and luster are not useful indicators of heat treatment by prehistoric peoples

Investigation of anodic oxide coatings on zirconium after heat treatment

International Nuclear Information System (INIS)

Sowa, Maciej; Dercz, Grzegorz; Suchanek, Katarzyna; Simka, Wojciech

2015-01-01

Highlights: • Oxide layers prepared via PEO of zirconium were subjected to heat treatment. • Surface characteristics were determined for the obtained oxide coatings. • Heat treatment led to the partial destruction of the anodic oxide layer. • Pitting corrosion resistance of zirconium was improved after the modification. - Abstract: Herein, results of heat treatment of zirconium anodised under plasma electrolytic oxidation (PEO) conditions at 500–800 °C are presented. The obtained oxide films were investigated by means of SEM, XRD and Raman spectroscopy. The corrosion resistance of the zirconium specimens was evaluated in Ringer's solution. A bilayer oxide coatings generated in the course of PEO of zirconium were not observed after the heat treatment. The resulting oxide layers contained a new sublayer located at the metal/oxide interface is suggested to originate from the thermal oxidation of zirconium. The corrosion resistance of the anodised metal was improved after the heat treatment

The Effect of Heat Treatment on the Crystallography and Mineral Magnetism of Pyrrhotite

Science.gov (United States)

Hobart, K.; Feinberg, J. M.; Jones, D. S.

2017-12-01

Pyrrhotite (Fe1-xS, 0 ≤ x ≤ 0.125) is the second most common sulfide mineral after pyrite in the Earth's crust, and its properties are of interest to a wide variety of scientific disciplines, including electrical engineering, physical chemistry, planetary geology and meteoritics, and economic geology. The physical properties of pyrrhotite are highly dependent on slight variations in composition and the ordering of iron vacancies, resulting in a number of possible phases between the endmember compositions of FeS and Fe7S8­­. A common complication in studies on pyrrhotite is that different phases are frequently intergrown, making it difficult to isolate a natural single phase. This has led many researchers to rely on synthesis techniques, which produce a specific structure by using precise iron/sulfur ratios, heating protocols, and controlled cooling. One of the most common synthesis treatments used to create 4C pyrrhotite is an extended heating and annealing process, which is believed to allow the reordering of vacancies to a more thermodynamically stable, ordered state with elevated saturation magnetization. The process was first studied in detail by Schwarz and Vaughan (1972) who produced synthetic pyrrhotite at varying Fe/S ratios with annealing at either 700, 300, or 144°C. The most common method for producing 4C pyrrhotite is heating at 500°C for 24 hours under a vacuum followed by annealing at 250°C for 50 hours. While this technique has been broadly applied in diverse disciplines, there is debate about whether it produces ferrimagnetic, monoclinic 4C pyrrhotite or a different metastable disordered phase. We examined this process using a combination of rock magnetic, X-ray diffraction, and electron imaging techniques to study the effect of heating and annealing on a natural sample of pyrrhotite. Due to the lack of a Besnus transition in the annealed material, our data suggest that the increased magnetization we found following annealing, rather than

Influence of Heat Treatment and UV Irradiation on the Wettability of Ti35Nb10Ta Nanotubes

Directory of Open Access Journals (Sweden)

Joan Lario

2018-01-01

Full Text Available The implant osseointegration rate depends on the surface’s topography and chemical composition. There is a growing interest in the anodic oxidation process to obtain an oxide layer with a nanotube morphology on beta titanium alloys. This surface treatment presents large surface area, nanoscale rugosity and electrochemical properties that may increase the biocompatibility and osseointegration rate in titanium implants. In this work, an anodic oxidation process was used to modify the surface on the Ti35Nb10Ta alloy to obtain a titanium nanotubes topography. The work focused on analyzing the influence of some variables (voltage, heat treatment and ultraviolet irradiation on the wettability performance of a titanium alloy. The morphology of the nanotubes surfaces was studied by Field Emission Scanning Electron Microscopy (FESEM, and surface composition was analyzed by Energy Dispersive Spectroscopy (EDS. The measurement of contact angle for the TiO2 nanotube surfaces was measured by a video contact angle system. The surface with the non photoinduced nanotubes presented the largest contact angles. The post-heat treatment lowered the F/Ti ratio in the nanotubes and decreased the contact angle. Ultraviolet (UV irradiation of the TiO2 nanotubes decrease the water contact angle.

Effect of heat treatment on yield and quality of loofah (luffa cylindrica linn.) seed oil

International Nuclear Information System (INIS)

Akinoso, R.

2015-01-01

Effect of heat treatment on yield and some quality parameters of loofah seed (Luffa cylindrical Linn.) oil was the focus of this study. Central composite rotatable response surface methodology design for two variables was used for this investigation. Fatty acid composition of the un-treated oil was determined. The independent variables roasting temperature were 102, 110, 130, 150, 158 degree C and duration 16, 20, 30, 40, 44 min while oil yield, moisture content, free fatty acid, colour, refractive index and specific gravity of the oil were the dependent variables. All determinations were done using standard methods. Linoleic acid (50.66%), oleic acid (27.66%), palmitic acid (12.28%) and stearic acid (6.44%) were the major fatty acids. Mean oil yield, moisture, free fatty acid, colour, refractive index and specific gravity were 25.9 ± 5.16%, 0.035 ± 0.003%, 5.3 ± 2.47%, 15.23 ± 1.83 mg/100g, 1.47 ± 0.002 ND 40 and 0.913 ± 0.02, respectively. All the parameters were significantly affected by heat treatment (p<0.05). Regression models were not fit to express the relation, thus optimisation using response surface approach was not adequate. (author)

Heat treatment temperature influence on ASTM A890 GR 6A super duplex stainless steel microstructure

International Nuclear Information System (INIS)

Martins, Marcelo; Casteletti, Luiz Carlos

2005-01-01

Duplex and super duplex stainless steels are ferrous alloys with up to 26% chromium, 8% nickel, 5% molybdenum and 0.3% nitrogen, which are largely used in applications in media containing ions from the halogen family, mainly the chloride ion (Cl - ). The emergence of this material aimed at substituting Copper-Nickel alloys (Cupro-Nickel) that despite presenting good corrosion resistance, has mechanical properties quite inferior to steel properties. The metallurgy of duplex and super duplex stainless steel is complex due to high sensitiveness to sigma phase precipitation that becomes apparent, due to the temperatures they are exposed on cooling from solidification as well as from heat treatment processes. The objective of this study was to verify the influence of heat treating temperatures on the microstructure and hardness of ASTM A890/A890M Gr 6A super duplex stainless steel type. Microstructure control is of extreme importance for castings, as the chemical composition and cooling during solidification inevitably provide conditions for precipitation of sigma phase. Higher hardness in these materials is directly associated to high sigma phase concentration in the microstructure, precipitated in the ferrite/austenite interface. While heat treatment temperature during solution treatment increases, the sigma phase content in the microstructure decreases and consequently, the material hardness diminishes. When the sigma phase was completely dissolved by the heat treatment, the material hardness was influenced only due to ferrite and austenite contents in the microstructure

Efficacy of heat treatment for disinfestation of concrete grain silos

Science.gov (United States)

Field experiments were conducted in 2007 and 2008 to evaluate heat treatment for disinfestations of empty concrete elevator silos. A Mobile Heat Treatment Unit was used to introduce heat into silos to attain target conditions of 50°C for at least 6 h. Ventilated plastic containers with a capacity of...

Saving energy resources during heat treatment - the most important problem of the branch

Energy Technology Data Exchange (ETDEWEB)

Zadernovskiy, V V; Firger, I V

1980-01-01

Natural gas fired thermal furnaces expend significantly less fuel than electric furnaces with an equal quality of metal heating. An important reserve in power reserve economy is the use of the forging heat in an article for heat treatment (TOB), where besides the power resources, metal is also saved as a result of the reduction in the volume of heating means and production spaces. From the experience in the progressive enterprises of the branch, in a number of cases it is possible to combine heating for plastic deformation with heating for primary or secondary heat treatment. Other measures are examined which save power resources in heat treatment: the use of thermal furnaces for aerodynamic heating, the use of local heat treatment, the reduction in the duration of the heat treatment processes, savings in the power carriers during heat treatment in furnaces with a roll out hearth. Fibrous refractory materials are being used more and more as fettling materials in the construction of thermal furnaces.

Untargeted analysis to monitor metabolic changes of garlic along heat treatment by LC-QTOF MS/MS.

Science.gov (United States)

Molina-Calle, María; Sánchez de Medina, Verónica; Calderón-Santiago, Mónica; Priego-Capote, Feliciano; Luque de Castro, María D

2017-09-01

Black garlic is increasing its popularity in cuisine around the world; however, scant information exists on the composition of this processed product. In this study, polar compounds in fresh garlic and in samples taken at different times during the heat treatment process to obtain black garlic have been characterized by liquid chromatography coupled to tandem mass spectrometry in high resolution mode. Ninety-five compounds (mainly amino acids and metabolites, organosulfur compounds, and saccharides and derivatives) were tentatively identified in all the analysed samples and classified as a function of the family they belong to. Statistical analysis of the results allowed establishing that the major changes in garlic occur during the first days of treatment, and they mainly affect to the three representative families. The main pathways involved in the synthesis of the compounds affected by heat treatment, and their evolution during the process were studied. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fast in situ X-ray diffraction phase and stress analysis during complete heat treatment cycles of steel

International Nuclear Information System (INIS)

Rocha, A. da S.; Hirsch, T.

2005-01-01

This paper presents results obtained with a method for time and temperature resolved analysis of changes in phase composition and stresses/residual stresses during complete heat treatment cycles of steel, including quenching. Sample temperatures of up to 930 deg. C could be reached with a specially designed furnace, where fast cooling of the samples was realized by gas quenching. Measurements for phase and stress analysis could be performed with an acquisition rate of at least one value every 3 s. Results concerning residual stress relaxation during heating, and stress/residual stress development during quenching are presented and discussed for AISI E52100 ball bearing steel. The observed stress development during quenching followed the expected transformation behavior with some deviations that could be explained through the effects of surface decarburization. The system developed proved to be a suitable tool for characterizing phase and stress changes that occur during heat treatment of steels, as a function of time and temperature

Preparation of fine powdered composite for latent heat storage

Energy Technology Data Exchange (ETDEWEB)

Fořt, Jan, E-mail: jan.fort.1@fsv.cvut.cz; Trník, Anton, E-mail: anton.trnik@fsv.cvut.cz; Pavlíková, Milena, E-mail: milena.pavlikova@fsv.cvut.cz; Pavlík, Zbyšek, E-mail: pavlikz@fsv.cvut.cz [Department of Materials Engineering and Chemistry, Faculty of Civil Engineering, Czech Technical University in Prague, Thákurova 7, 166 29 Prague (Czech Republic); Pomaleski, Marina, E-mail: marina-pomaleski@fsv.cvut.cz [Faculty of Civil Engineering, Architecture and Urbanism, University of Campinas, R. Saturnino de Brito 224, 13083-889 Campinas – SP (Brazil)

2016-07-07

Application of latent heat storage building envelope systems using phase-change materials represents an attractive method of storing thermal energy and has the advantages of high-energy storage density and the isothermal nature of the storage process. This study deals with a preparation of a new type of powdered phase change composite material for thermal energy storage. The idea of a composite is based upon the impregnation of a natural silicate material by a reasonably priced commercially produced pure phase change material and forming the homogenous composite powdered structure. For the preparation of the composite, vacuum impregnation method is used. The particle size distribution accessed by the laser diffraction apparatus proves that incorporation of the organic phase change material into the structure of inorganic siliceous pozzolana does not lead to the clustering of the particles. The compatibility of the prepared composite is characterized by the Fourier transformation infrared analysis (FTIR). Performed DSC analysis shows potential of the developed composite for thermal energy storage that can be easily incorporated into the cement-based matrix of building materials. Based on the obtained results, application of the developed phase change composite can be considered with a great promise.

Low temperature heat treatments of AA5754-Ti6Al4V dissimilar laser welds: Microstructure evolution and mechanical properties

Science.gov (United States)

Leo, P.; D'Ostuni, S.; Casalino, G.

2018-03-01

This paper presents the effects of the post welding heat treatments (PWHT) performed at 350 °C and 450 °C on the microstructure evolution and mechanical properties of AA5754 and Ti6Al4V dissimilar laser welds. The microstructure and tensile properties of the welds before and after low temperature treatment were analyzed. The off-set welding technique was applied to limit the formation of brittle intermetallic compounds during the welding process. The laser beam was directed onto the titanium side at a small distance from the aluminum edge. The keyhole formed and the full penetration was reached in the titanium side of the weld. Thereafter, the aluminum side melted as the heat that formed the keyhole transferred from the titanium fused zone. Two different energy lines (32 J/mm and 76 J/mm) were used. In this manner, a fused and a heat affected zones was revealed on both sides of the weld. Several intermetallic compounds formed in the intermetallic layer between the two metals. The thickness and the composition of the intermetallic layer depended on the welding parameters and the post welding heat treatment. The hardness and tensile properties of the welds before and after the post welding heat treatment were measured and analyzed.

New Nomenclatures for Heat Treatments of Additively Manufactured Titanium Alloys

Science.gov (United States)

Baker, Andrew H.; Collins, Peter C.; Williams, James C.

2017-07-01

The heat-treatment designations and microstructure nomenclatures for many structural metallic alloys were established for traditional metals processing, such as casting, hot rolling or forging. These terms do not necessarily apply for additively manufactured (i.e., three-dimensionally printed or "3D printed") metallic structures. The heat-treatment terminology for titanium alloys generally implies the heat-treatment temperatures and their sequence relative to a thermomechanical processing step (e.g., forging, rolling). These designations include: β-processing, α + β-processing, β-annealing, duplex annealing and mill annealing. Owing to the absence of a thermomechanical processing step, these traditional designations can pose a problem when titanium alloys are first produced via additive manufacturing, and then heat-treated. This communication proposes new nomenclatures for heat treatments of additively manufactured titanium alloys, and uses the distinct microstructural features to provide a correlation between traditional nomenclature and the proposed nomenclature.

First order reversal curve analysis on NdFeB nanocomposite ribbons subjected to Joule heating treatments

Energy Technology Data Exchange (ETDEWEB)

Pampillo, L.G. [INTECIN-Instituto de Tecnologias y ciencias de la Ingenieria ' Hilario Fernandez Long' (UBA-CONICET), Facultad de Ingenieria, Paseo Colon 850 (C1063ACV), C. A. B. A. (Argentina); Saccone, F.D., E-mail: fsaccone@fi.uba.ar [INTECIN-Instituto de Tecnologias y ciencias de la Ingenieria ' Hilario Fernandez Long' (UBA-CONICET), Facultad de Ingenieria, Paseo Colon 850 (C1063ACV), C. A. B. A. (Argentina); Knobel, M. [Instituto de Fisica Gleb Wataghin-Departamento de Fisica de Materia Condensada-Universidade Estadual de Campinas, Cidade Universitaria Zeferino Vaz, Barao Geraldo 13083-970, Campinas, Sao Paulo (Brazil); Sirkin, H.R.M. [INTECIN-Instituto de Tecnologias y ciencias de la Ingenieria ' Hilario Fernandez Long' (UBA-CONICET), Facultad de Ingenieria, Paseo Colon 850 (C1063ACV), C. A. B. A. (Argentina)

2012-09-25

Highlights: Black-Right-Pointing-Pointer Nd-lean amorphous precursors subjected to Joule heating. Black-Right-Pointing-Pointer Exchange-spring magnets. Black-Right-Pointing-Pointer FORC diagrams of irreversible switching fields. Black-Right-Pointing-Pointer This last techniques helped us to verify the optimized treatments conditions. - Abstract: Amorphous precursors with composition Nd{sub 4.5}Fe{sub 72-x}Co{sub 3+x}Cr{sub 2}Al{sub 1}B{sub 17.5} (x = 0, 2, 7, 12) were thermally treated by the Joule heating technique with a linearly varying electrical current. The crystallization kinetics was followed by monitoring the resistance of the ribbons during the heating up to the final applied current. Crystallized nanostructured phases coexist with an amorphous matrix, as it was observed by means of Moessbauer Spectroscopy and X-ray diffraction. The irreversible magnetic response of the Joule heated ribbons was analyzed by the First Order Reversal Curves (FORC) diagram technique. For the optimal treatments, associated with the higher maximum energy products for each sample composition, it was found that the main interaction is of a strongly dipolar characteristic. Over annealed samples show a FORC diagram that gives into account of softening, due to grain growth, for those phases precipitated at the first crystallization stage. When it is measured at 20 K, the hardest magnetic sample (Fe = 72 at.%, Co = 3 at.%, I{sub final} = 0.5 A), exhibits a diagram with characteristics corresponding to dipolar interactions of soft phases. This fact is consistent with an enhancement of the exchange length due to the increase in the soft phase stiffness as it is expected at low temperatures.

Characterization of microstructure and surface properties of hybrid coatings of WC-CoCr prepared by laser heat treatment and high velocity oxygen fuel spraying

International Nuclear Information System (INIS)

Zhang Shihong; Cho, Tong-Yul; Yoon, Jae-Hong; Fang, Wei; Song, Ki-O; Li Mingxi; Joo, Yun-Kon; Lee, Chan Gyu

2008-01-01

The microstructure and microhardness of high velocity oxygen fuel-sprayed WC-CoCr coatings were comparatively studied both before and after laser heat treatment of the coatings. Optical microscopy, scanning electron microscopy, X-ray diffraction and microhardness testing were applied to investigate the microstructure, phase composition, porosity and microhardness. The results indicate that WC is still present, and W 2 C has appeared, while neither cobalt nor σ-CrCo is detectable. Co 4 W 2 C has appeared in the high velocity oxygen fuel-sprayed coating after laser heat treatment as compared to the coating before laser treatment. The relative content of the W 2 C has not increased with laser treatment, but the laser treatment has essentially eliminated the porosity almost entirely, providing a more homogeneous and densified microstructure. The laser heat treatment has effected the formation of a denser compact coating on the substrate. After laser heat treatment, the thickness of the coating has decreased from 300 μm to 225 μm. This corresponds to an average porosity in the high velocity oxygen fuel-sprayed coating that is approximately five times greater than that in the subsequently laser heat-treated coating. The laser treatment has also resulted in an increased hardness of the coating near the surface, where the average value increased from Hv 0.2 = 1262.4 in the coating before laser heat treatment to Hv 0.2 = 1818.7 after laser heat treatment

Synthesis and heating effect of iron/iron oxide composite and iron oxide nanoparticles.

Science.gov (United States)

Zeng, Q; Baker, I; Loudis, J A; Liao, Y F; Hoopes, P J

2007-02-09

Fe/Fe oxide nanoparticles, in which the core consists of metallic Fe and the shell is composed of Fe oxides, were obtained by reduction of an aqueous solution of FeCl 3 within a NaBH 4 solution, or, using a water-in-oil micro-emulsion with CTAB as the surfactant. The reduction was performed either in an inert atmosphere or in air, and passivation with air was performed to produce the Fe/Fe 3 O 4 core/shell composite. Phase identification and particle size were determined by X-ray diffraction and TEM. Thermal analysis was performed using a differential scanning calorimeter. The quasistatic magnetic properties were measured using a VSM, and the specific absorption rates (SARs) of both Fe oxide and Fe/Fe 3 O 4 composite nanoparticles either dispersed in methanol or in an epoxy resin were measured by Luxtron fiber temperature sensors in an alternating magnetic field of 150 Oe at 250 kHz. It was found that the preparation conditions, including the concentrations of solutions, the mixing procedure and the heat treatment, influence the particle size, the crystal structure and consequently the magnetic properties of the particles. Compared with Fe oxides, the saturation magnetization ( M S ) of Fe/Fe 3 O 4 particles (100-190 emu/g) can be twice as high, and the coercivity ( H C ) can be tunable from several Oe to several hundred Oe. Hence, the SAR of Fe/Fe 3 O 4 composite nanoparticles can be much higher than that of Fe oxides, with a maximum SAR of 345 W/g. The heating behavior is related to the magnetic behavior of the nanoparticles.

Aeroplastic, New Composite Materials with Reduced Heat Transfer and Increased Flame Retardancy

Science.gov (United States)

Williams, Martha K.; Smith, Trent M.; Nichols, James D.; Roberson, Luke B.; Tate, Lanetra C.

2015-01-01

A new composite system formulated using commodity grade and engineered grade polymers. The composites can be fabricated into fibers, molded, or otherwise processed into useable articles. Use of this technology reduces the thermal conductivity and peak heat releases rates of the base polymer between 20%-50% while maintaining or enhancing the mechanical properties..

Fully coupled heat conduction and deformation analyses of nonlinear viscoelastic composites

KAUST Repository

Khan, Kamran; Muliana, Anastasia Hanifah

2012-01-01

This study presents an integrated micromechanical model-finite element framework for analyzing coupled heat conduction and deformations of particle-reinforced composite structures. A simplified micromechanical model consisting of four sub-cells, i

Technical project of complex fast cycle heat treatment of hydrogenous coal preparation

OpenAIRE

Moiseev, V. A.; Andrienko, V. G.; Pileckij, V. G.; Urvancev, A. I.; Gvozdyakov, Dmitry Vasilievich; Gubin, Vladimir Evgenievich; Matveev, Aleksandr Sergeevich; Savostiyanova, Ludmila Viktorovna

2015-01-01

Problems of heat-treated milled hydrogenous coal preparation site creation in leading fast cycle heat treatment complex were considered. Conditions for effective use of electrostatic methods of heat-treated milled hydrogenous coal preparation were set. Technical project of heat treatment of milled hydrogenous coal preparation site was developed including coupling of working equipment complex on fast heat treatment and experimental samples of equipment being designed for manufacturing. It was ...

Drought and heat stress effects on soybean fatty acid composition and oil stability

Science.gov (United States)

Previous studies have shown that oil concentration and fatty acid profile (composition) change with genotype, environment (mainly heat and drought), and geographical location. The changes in fatty acid composition under these conditions affect fatty acid stability, creating a challenge to oil proces...

Influence of heat treatment on corrosive resistance of concrete steels

International Nuclear Information System (INIS)

Woldan, A.; Suliga, I.; Kusinski, J.; Jazowy, R.

1998-01-01

The reinforcing bars are essential elements of ferro-concrete structures. During the building structure service the reinforcing bars should co-operate with surrounding concrete. Any bonding defects as well as corrosion induced strength reduction may result in construction failure. The reinforcing steel working environment is determined by concrete chemical and phase composition and surrounding environmental properties. The aggressive corrosive activity of the letter implies necessity of effective ways development to protect elements against corrosion. The effect of heat treatment, increased Si content in steel on corrosion resistance of reinforcing steel in concrete was studied in the current work. Corrosion tests and metallographic examinations proved a positive influence of hardening and Si enrichment on corrosion resistance of reinforcing bars in ferro-concrete structures. (author)

Corrosion Behaviour of Heat - Treated Al-6063/ SiCp Composites Immersed in 5 wt% NaCl Solution

Directory of Open Access Journals (Sweden)

Kenneth ALANEME

2011-06-01

Full Text Available The influence of SiC volume percent and temper conditions (namely, as-cast, solutionized, and artificial age hardening at 180°C and 195°C on the corrosion behaviour of Al (6063 composites and its monolithic alloy immersed in 5wt% NaCl solution has been investigated. Al (6063 - SiC particulate composites containing 6, 12 and 15 volume percent SiC were produced by premixing the SiC particles with borax additive and then adopting two step stir casting. Mass loss and corrosion rate measurements were utilized as criteria for evaluating the corrosion behaviour of the composites. The results show that the corrosion susceptibility of the Al (6063 - SiCp composites was higher than that of the monolithic alloy, and for most cases the corrosion rate of the composites increased with increase in volume percent of SiC. However, it was discovered that the nature of the passive films formed on the composites was sufficiently stable to reduce significantly the corrosion rate of the composites after 13days of immersion. This trend was observed to be consistent for all heat-treatment conditions utilized.

A New Adsorbent Composite Material Based on Metal Fiber Technology and Its Application in Adsorption Heat Exchangers

Directory of Open Access Journals (Sweden)

Ursula Wittstadt

2015-08-01

Full Text Available In order to achieve process intensification for adsorption chillers and heat pumps, a new composite material was developed based on sintered aluminum fibers from a melt-extraction process and a dense layer of silico-aluminophosphate (SAPO-34 on the fiber surfaces. The SAPO-34 layer was obtained through a partial support transformation (PST process. Preparation of a composite sample is described and its characteristic pore size distribution and heat conductivity are presented. Water adsorption data obtained under conditions of a large pressure jump are given. In the next step, preparation of the composite was scaled up to larger samples which were fixed on a small adsorption heat exchanger. Adsorption measurements on this heat exchanger element that confirm the achieved process intensification are presented. The specific cooling power for the adsorption step per volume of composite is found to exceed 500 kW/m3 under specified conditions.

Effect of heat treatment on the crystal structure, martensitic transformation and magnetic properties of Mn{sub 53}Ni{sub 25}Ga{sub 22} ferromagnetic shape memory alloy

Energy Technology Data Exchange (ETDEWEB)

Dong, G.F., E-mail: dgfu0451@sina.com [Department of mechanics Dalian University, Dalian 116622 (China); Gao, Z.Y. [National Key Laboratory Precision Hot Processing of Metals, School of Materials Science and Engineering, Harbin Institute of Technology, P.O. Box 405, Harbin 150001 (China)

2016-02-01

In this study, the effect of heat treatment on crystal structure, martensitic transformation, thermodynamic behavior and magnetic properties of polycrystalline Mn{sub 53}Ni{sub 25}Ga{sub 22} ferromagnetic shape memory alloy was systematically investigated. The results show that the heat treatment has obvious effect on martensitic transformation temperatures, crystal structure and hysteresis loops. Heat treatment greatly effects on transformation temperatures due to modified composition of the matrix. Martensitic transformation temperature, saturation magnetization decreased with the increase heat treatment temperature, reaching their minimum values at the heat treatment temperature of 1173 K for 12 h. Curie temperature of maximum values obtained at solution-treated of 1173 K for 12 h. In other word, increasing heat treatment temperature and time has an effect on Curie temperature. In addition, the annealed alloy Mn{sub 53}Ni{sub 25}Ga{sub 22} may completely dissolve in vacuum tubes at 1173 K for 12 h. It is found that the studied alloys have some (Mn,Ni){sub 4} Ga-type compound precipitates, which can be seen dispersing both in grain interiors and on grain boundaries at other heat treatment process. Lastly, Rietveld analysis shows the good agreement between experiment and calculated data of XRD patterns. - Highlights: • Heat treatment has obvious effect on transformation, structure and hysteresis. • Transformation temperature decreased with increase heat treatment temperature. • Magnetization decreased with increase heat treatment temperature. • Annealed alloy completely dissolve in vacuum tubes at 1123 K for 24 h.

Effect of heat treatment on structure and magnetic properties

Indian Academy of Sciences (India)

Fe46Co35Ni19/CNTs nanocomposites have been prepared by an easy two-step route including adsorption and heat treatment processes. We investigated the effect of heat treatment conditions on structure, morphology, nanoparticle sizes and magnetic properties of the Fe46Co35Ni19 alloy nanoparticles attached on the ...

Specific heat of nano-ferrites modified composites

Directory of Open Access Journals (Sweden)

Muntenita Cristian

2017-01-01

Full Text Available The specific heat of nano-ferrites modified composites was studied using differential scanning calorimeter (DSC method in the temperature range of 30 to 150°C. Initially, nano-ferrites were introduced in epoxy systems in order to improve the electromagnetic properties of formed materials. Together with the changes in electromagnetic properties some modifications occur regarding thermal and mechanical properties. The materials were formed by placing 5g or 10g of ferrite into 250g polymer matrix leading to a very low weight ratio of modifying agent. At so low ratios the effect of ferrite presence should be insignificant according to mixing rule. Anyway there is possible to appear some chelation reaction with effects on thermal properties of materials. Three types of epoxy resins had been used as matrix and barium ferrite and strontium ferrite as modifying agents. The thermal analysis was developed on two heatingcooling cycles and the specific heat was evaluated for each segment of the cycle analysis.

Heat treatment of cathodic arc deposited amorphous hard carbon films

Energy Technology Data Exchange (ETDEWEB)

Anders, S.; Ager, J.W. III; Brown, I.G. [and others

1997-02-01

Amorphous hard carbon films of varying sp{sup 2}/sp{sup 3} fractions have been deposited on Si using filtered cathodic are deposition with pulsed biasing. The films were heat treated in air up to 550 C. Raman investigation and nanoindentation were performed to study the modification of the films caused by the heat treatment. It was found that films containing a high sp{sup 3} fraction sustain their hardness for temperatures at least up to 400 C, their structure for temperatures up to 500 C, and show a low thickness loss during heat treatment. Films containing at low sp{sup 3} fraction graphitize during the heat treatment, show changes in structure and hardness, and a considerable thickness loss.

Effect of heat treatment and hot isostatic pressing on the microstructure and mechanical properties of Inconel 625 alloy processed by laser powder bed fusion

Energy Technology Data Exchange (ETDEWEB)

Kreitcberg, Alena, E-mail: alena.kreitcberg.1@ens.etsmtl.ca [École de technologie supérieure, 110 Notre-Dame Street West, Montreal, Quebec H3C 1K3 Canada (Canada); Brailovski, Vladimir, E-mail: vladimir.brailovski@etsmtl.ca [École de technologie supérieure, 110 Notre-Dame Street West, Montreal, Quebec H3C 1K3 Canada (Canada); Turenne, Sylvain, E-mail: sylvain.turenne@polymtl.ca [École Polytechnique de Montréal, 2900 boul. Édouard-Montpetit, Montreal, Quebec H3T 1J4 Canada (Canada)

2017-03-24

The effect of different heat treatments and hot isostatic pressing on the microstructure and mechanical properties of laser powder bed fusion IN625 alloy was studied. The heat treatments were: stress relief annealing, recrystallization annealing and low-temperature solution treatment. The resulting microstructure and crystallographic textures were studied using optical and scanning electron microscopy. The mechanical properties of the as-built and post-treated IN625 alloy were obtained after tensile testing at room temperature and at 760 °C (1400 °F), and compared to those of an annealed wrought alloy of the same composition.

Arbuscular mycorrhizal fungi modify nutrient allocation and composition in wheat (Triticum aestivum L.) subjected to heat-stress

DEFF Research Database (Denmark)

Cabral, Carmina; Ravnskov, Sabine; Tringovska, Ivanka

2016-01-01

- and micronutrient concentrations in aboveground biomass; evaluation of AM fungal structures in roots and assessment of light-use efficiency of plants. Results AM increased grain number in wheat under heat-stress, and altered nutrient allocation and tiller nutrient composition. Heat increased number of arbuscules...... in wheat root, whereas number of vesicles and total colonization were unaffected. Heat increased photosystem II yield and the electron transfer rate, whereas non-photochemical quenching decreased during the first 2 days of heat-stress. Conclusions Nutrient allocation and –composition in wheat grown under...

Enhanced Thermo-Optical Switching of Paraffin-Wax Composite Spots under Laser Heating.

Science.gov (United States)

Said, Asmaa; Salah, Abeer; Fattah, Gamal Abdel

2017-05-12

Thermo-optical switches are of particular significance in communications networks where increasingly high switching speeds are required. Phase change materials (PCMs), in particular those based on paraffin wax, provide wealth of exciting applications with unusual thermally-induced switching properties, only limited by paraffin's rather low thermal conductivity. In this paper, the use of different carbon fillers as thermal conductivity enhancers for paraffin has been investigated, and a novel structure based on spot of paraffin wax as a thermo-optic switch is presented. Thermo-optical switching parameters are enhanced with the addition of graphite and graphene, due to the extreme thermal conductivity of the carbon fillers. Differential Scanning Calorimetry (DSC) and Scanning electron microscope (SEM) are performed on paraffin wax composites, and specific heat capacities are calculated based on DSC measurements. Thermo-optical switching based on transmission is measured as a function of the host concentration under conventional electric heating and laser heating of paraffin-carbon fillers composites. Further enhancements in thermo-optical switching parameters are studied under Nd:YAG laser heating. This novel structure can be used in future networks with huge bandwidth requirements and electric noise free remote aerial laser switching applications.

Structure and composition of enamel and dentin after thermal treatment or infrared laser irradiation

International Nuclear Information System (INIS)

Bachmann, Luciano

2004-01-01

The main purpose of this work is to identify the crystallographic structure, optical properties, chemical composition and electron paramagnetic signals that laser irradiation or oven heating produces on the tissue. The thermal treatment was conducted in oven with temperature range below 1000 deg C and the laser irradiation with holmium (Ho:YLF - 2,065 μm) and erbium (Er:YAG - 2,94 μm) laser. The tissue characterization was carried out with X-ray diffraction, scanning electron microscopy, ultraviolet and visible transmission spectroscopy, light microscopy, infrared transmission/reflection spectroscopy and electron paramagnetic resonance. The holmium irradiated enamel (600-800 J/cm 2 ) shows the presence of tetracalcium phosphate that coexists with the natural phase (hydroxyapatite). The irradiated dentin shows only the sharper diffraction peaks of the natural phase. The narrows peaks, observed after irradiation, could be assigned to the dentin crystal growth and impurities elimination. Tissue discoloration is observed after thermal treatment with temperatures above 100 deg C. Heated enamel become white-opaque and the origin is assigned to the water elimination, which promotes higher light scattering by the prismatic structure. On the other hand, heated dentin, with similar temperatures becomes brown. The dentin browning changes with the temperature and shown two peaks, at 375 deg C and 700 deg C. The peak at 375 deg C is assigned to the collagen structure degradation and at 700 deg C to the cyanate formation. The dentin discoloration produced with temperatures below 200 deg C is reversible after the tissue hydration. Both enamel and dentin discoloration are also observed in erbium irradiated tissues. Thermal treatments, heating in oven or laser irradiation, change mainly the organic matrix composition and water present in the tissues. The inorganic matrix is more stable and its radicals are changed, with more predominance, only at temperatures higher than 500 deg

Effects of Heat Stress on Metabolite Accumulation and Composition, and Nutritional Properties of Durum Wheat Grain

Directory of Open Access Journals (Sweden)

Anna Maria de Leonardis

2015-12-01

Full Text Available Durum wheat (Triticum turgidum (L. subsp. turgidum (L. convar. durum (Desf. is momentous for human nutrition, and environmental stresses can strongly limit the expression of yield potential and affect the qualitative characteristics of the grain. The aim of this study was to determine how heat stress (five days at 37 °C applied five days after flowering affects the nutritional composition, antioxidant capacity and metabolic profile of the grain of two durum wheat genotypes: “Primadur”, an elite cultivar with high yellow index, and “T1303”, an anthocyanin-rich purple cultivar. Qualitative traits and metabolite evaluation (by gas chromatography linked to mass spectrometry were carried out on immature (14 days after flowering and mature seeds. The effects of heat stress were genotype-dependent. Although some metabolites (e.g., sucrose, glycerol increased in response to heat stress in both genotypes, clear differences were observed. Following the heat stress, there was a general increase in most of the analyzed metabolites in “Primadur”, with a general decrease in “T1303”. Heat shock applied early during seed development produced changes that were observed in immature seeds and also long-term effects that changed the qualitative and quantitative parameters of the mature grain. Therefore, short heat-stress treatments can affect the nutritional value of grain of different genotypes of durum wheat in different ways.

Fabrication techniques to eliminate postweld heat treatment

International Nuclear Information System (INIS)

Lochhead, J.C.

1978-01-01

Postweld heat treatments to reduce residual stresses (stress relief operations) have been a common practice in the pressure vessel industry for a large number of years. A suitable heat treatment operation can, in particular for low alloy steels, have additional beneficial effects, i.e. a reduction in peak hardness values in the heat-affected zone, an improvement in weld metal properties, and a lowering of the adverse effects of the welding process on the mechanical properties of the parent material adjacent to the weld metal. However, continuing studies in the field of brittle fracture, improved parent materials, and more sophisticated nondestructive testing techniques have led to the elimination of such a practice in ever-increasing thickness ranges and types of material. For instance, the recently issued BS 5500 compared with BS 1113 (1969) lifts the thickness limit requiring stress relief in certain circumstances from 19 to 35mm for C steels. With respect to materials the CEGB has stated that as a result of successful operational experience it will no longer be necessary to postweld heat treat butt welds in 2 1/4 Cr-1Mo tubes of certain dimensions. Despite this trend, over a period of years a number of instances have arisen where, because of some factor, postweld heat treatment, although perhaps desirable, is not possible. This Paper describes several such examples. It must be noted that the examples quoted consist of relatively important and major items. It has been necessary within the confines of this Paper to condense the reports. It is hoped that no significant factors have been omitted. (author)

Carcass composition of market weight pigs subjected to heat stress in utero and during finishing.

Science.gov (United States)

Cruzen, S M; Boddicker, R L; Graves, K L; Johnson, T P; Arkfeld, E K; Baumgard, L H; Ross, J W; Safranski, T J; Lucy, M C; Lonergan, S M

2015-05-01

Objectives were to investigate the effects of prolonged gestational and/or postnatal heat stress on performance and carcass composition of market weight pigs. Pregnant gilts were exposed to gestational heat stress (GHS, 28°C to 34°C, diurnal) or thermal neutral (18°C to 22°C, diurnal) conditions during the entire gestation or during the first or second half of gestation. At 14 wk of age (58 ± 5 kg), barrows were housed in heat stress (32°C, HS) or thermal neutral (21°C, TN) conditions. Feed intake and BW were recorded weekly, and body temperature parameters were monitored twice weekly until slaughter (109 ± 5 kg). Organs were removed and weighed, and loin eye area (LEA) and back fat thickness (BF) were measured after carcass chilling. Carcass sides were separated into lean, separable fat, bone, and skin components and were weighed. Moisture, lipid, and protein content were determined in the LM at the 10th rib. Data were analyzed using a split plot with random effect of dam nested within gestational treatment. Carcass measurements included HCW as a covariate to control for weight. Planned orthogonal contrast statements were used to evaluate the overall effect of GHS in the first half, second half, or any part of gestation. Gestational heat stress did not alter postnatal performance or most body temperature parameters (P > 0.10). However, ADFI in the finishing period was increased (P carcasses (P = 0.38). Carcasses from HS barrows also had less carcass separable fat (P carcasses had a greater moisture to protein ratio (P = 0.04). HS barrows also had decreased heart (P carcass composition. Chronic HS during finishing results in longer times to reach market weight and a leaner carcass once market weight is achieved.

An investigation into the effects of conventional heat treatments on mechanical characteristics of new hot working tool steel

Science.gov (United States)

Fares, M. L.; Athmani, M.; Khelfaoui, Y.; Khettache, A.

2012-02-01

The effects of conventional heat treatments, i.e. quenching and tempering, on the mechanical characteristics of non standard hot work tool steel, close to either AISI-H11/H13 are investigated. The major elemental composition differences are in carbon, silicon and vanadium. The objective of the carried heat treatments is to obtain an efficient tool performance in terms of hardness, wear resistance and mechanical strength. Experimental results allow an explanation of the surface properties depending mainly on both chemical composition and optimised preheating parameters. After austenitizing at 1050 °C for 15 min, the as-quenched steel in oil bath exhibited the fully martensitic structure (without bainite) connected to a small fraction of retained austenite and complex carbides mainly of M23C6 type. Twice tempering at 500 °C and 600 °C resulted in initiating the precipitation processes and the secondary hardness effect. As a result, carbide content amounted to 3% while the retained austenite content decreased to 0%. Accordingly, the required mechanical properties in terms of hardness and wear are fulfilled and are adequately favourable in handling both shocks and pressures for the expected tool life. Induced microstructures are revealed using optical and scanning electron microscopes. Phase compositions are assessed by means of X-ray diffraction technique while mechanical characteristics are investigated based on hardness and abrasive wear standard tests.

Effect of heat treatment temperature on binder thermal conductivities

International Nuclear Information System (INIS)

Wagner, P.

1975-12-01

The effect of heat treatment on the thermal conductivities of a pitch and a polyfurfuryl alcohol binder residue was investigated. Graphites specially prepared with these two binders were used for the experiments. Measured thermal conductivities were treated in terms of a two-component system, and the binder thermal conductivities were calculated. Both binder residues showed increased thermal conductivity with increased heat treatment temperature

Impact of Heat-Shock Treatment on Yellowing of Pak Choy Leaves

Institute of Scientific and Technical Information of China (English)

WANG Xiang-yang; SHEN Lian-qing; YUAN Hai-na

2004-01-01

The physiological mechanism of maintaining the green colour of pak choy leaves (Brassica rapa var chinensis) with heat-shock treatment was studied. Chlorophyll in the outer leaves of pak choy degraded rapidly during storage at ambient temperature (20 ± 2℃), a slight yellow appeared. Heat-shock treatment (46- 50℃) had a mild effect on maintaining the green colour of outer leaves. Normal chlorophyll degradation was associated with a binding of chlorophyll with chlorophyll-binding-protein preceding chlorophyll breakdown.Heat-shock treatment was found to reduce the binding-capacity between chlorophyllbinding-protein and chlorophyll. In the chlorophyll degradation pathway, pheide dioxygenase was synthesized during leaf senescence which was considered to be a key enzyme in chlorophyll degradation. Activity of this enzyme was reduced following heat-shock treatment, which might explain the observed reduction in chlorophyll breakdown. Two groups of heat-shock proteins were detected in treated leaves, the first group containing proteins from 54KDa to 74 Kda, and the second group contained proteins from 15 KDa to 29KDa. Heat-shock treatment was also found to retard the decline of glucose and fructose (the main energy substrates) of outer leaves.

Application of tungsten-fibre-reinforced copper matrix composites to a high-heat-flux component: A design study by dual scale finite element analysis

International Nuclear Information System (INIS)

Jeong-Ha You

2006-01-01

According to the European Power Plant Conceptual Study, actively cooled tungsten mono-block is one of the divertor design options for fusion reactors. In this study the coolant tube acts as a heat sink and the tungsten block as plasma-facing armour. A key material issue here is how to achieve high temperature strength and high heat conductivity of the heat sink tube simultaneously. Copper matrix composite reinforced with continuous strong fibres has been considered as a candidate material for heat sink of high-heat-flux components. Refractory tungsten wire is a promising reinforcement material due to its high strength, winding flexibility and good interfacial wetting with copper. We studied the applicability of tungsten-fibre-reinforced copper matrix composite heat sink tubes for the tungsten mono-block divertor by means of dual-scale finite element analysis. Thermo-elasto-plastic micro-mechanics homogenisation technique was applied. A heat flux of 15 MW/m 2 with cooling water temperature of 320 o C was considered. Effective stress-free temperature was assumed to be 500 o C. Between the tungsten block and the composite heat sink tube interlayer (1 mm thick) of soft Cu was inserted. The finite element analysis yields the following results: The predicted maximum temperature at steady state is 1223 o C at the surface and 562 o C at the interface between tube and copper layer. On the macroscopic scale, residual stress is generated during fabrication due to differences in thermal expansion coefficients of the materials. Strong compressive stress occurs in the tungsten block around the tube while weak tensile stress is present in the interlayer. The local and global probability of brittle failure of the tungsten block was also estimated using the probabilistic failure theories. The thermal stresses are significantly decreased upon subsequent heat flux loading. Resolving the composite stress on microscopic scale yields a maximum fibre axial stress of 3000 MPa after

Effects of heat treatment on the radiosensitivity of Salmonellae

International Nuclear Information System (INIS)

Choi, E.H.; Yang, J.S.; Lee, S.R.

1978-01-01

When the food poisoning bacteria Salmonella enteritidis and S. typhimurium were treated with radiation (cobalt-60 γ-rays) and heat (10 minutes at 45 0 C or 50 0 C), their sterilizing effect was revealed differently depending on the order of treatments. Post-irradiation heating showed a synergistic effect whereas pre-irradiation heating revealed the opposite effect and the effects differed slightly with heating temperature. (author)

Novel magnetic heating probe for multimodal cancer treatment.

Science.gov (United States)

Kan-Dapaah, Kwabena; Rahbar, Nima; Soboyejo, Wole

2015-05-01

Multifunctional materials consisting of polymers and magnetic nanoparticles (MNPs) are highly sought after in the field of biomedical engineering. These materials offer new opportunities for the development of novel cancer treatment modalities that can increase the efficacy of cancer therapy. In this paper, a novel probe for multimodal cancer treatment is proposed and analyzed. The probe is essentially a cannula with two main parts: a distal heat generating tip made of a magnetic nanocomposite and a proximal insulated shaft. A description of the concept and functional operations of the probe is presented. In an effort to assess its feasibility, the authors evaluated the ability of probe tip (made of PMMA-Fe3O4 nanocomposite) to generate heat in biological tissue using alternating magnetic field (AMF) parameters (field strength and frequency) that are acceptable for human use. Heat generation by MNPs was determined using the linear response theory. The effects of Fe3O4 volume fraction on heat generation as well as treatment time on the thermal dose were studied. The finite element method model was tested for its validity using an analytical model. Lesions were revealed to have an ellipsoidal shape and their sizes were affected by treatment time. However, their shapes remained unchanged. The comparison with the analytical model showed reasonably a good agreement to within 2%. Furthermore, the authors' numerical predictions also showed reasonable agreement with the experimental results previously reported in the literature. The authors' predictions demonstrate the feasibility of their novel probe to achieve reasonable lesion sizes, during hyperthermic or ablative heating using AMF parameters (field strength and frequency) that are acceptable for human use.

Heat treatment giving a stable high temperature micro-structure in cast austenitic stainless steel

Science.gov (United States)

Anton, Donald L.; Lemkey, Franklin D.

1988-01-01

A novel micro-structure developed in a cast austenitic stainless steel alloy and a heat treatment thereof are disclosed. The alloy is based on a multicomponent Fe-Cr-Mn-Mo-Si-Nb-C system consisting of an austenitic iron solid solution (.gamma.) matrix reinforced by finely dispersed carbide phases and a heat treatment to produce the micro-structure. The heat treatment includes a prebraze heat treatment followed by a three stage braze cycle heat treatment.

Electro-thermo-mechanical coupling analysis of deep drawing with resistance heating for aluminum matrix composites sheet

Science.gov (United States)

Zhang, Kaifeng; Zhang, Tuoda; Wang, Bo

2013-05-01

Recently, electro-plastic forming to be a focus of attention in materials hot processing research area, because it is a sort of energy-saving, high efficient and green manufacturing technology. An electro-thermo-mechanical model can be adopted to carry out the sequence simulation of aluminum matrix composites sheet deep drawing via electro-thermal coupling and thermal-mechanical coupling method. The first step of process is resistance heating of sheet, then turn off the power, and the second step is deep drawing. Temperature distribution of SiCp/2024Al composite sheet by resistance heating and sheet deep drawing deformation were analyzed. During the simulation, effect of contact resistances, temperature coefficient of resistance for electrode material and SiCp/2024Al composite on temperature distribution were integrally considered. The simulation results demonstrate that Sicp/2024Al composite sheet can be rapidly heated to 400° in 30s using resistances heating and the sheet temperature can be controlled by adjusting the current density. Physical properties of the electrode materials can significantly affect the composite sheet temperature distribution. The temperature difference between the center and the side of the sheet is proportional to the thermal conductivity of the electrode, the principal cause of which is that the heat transfers from the sheet to the electrode. SiCp/2024Al thin-wall part can be intactly manufactured at strain rate of 0.08s-1 and the sheet thickness thinning rate is limited within 20%, which corresponds well to the experimental result.

Effect of pre-heating on the viscosity and microhardness of a resin composite.

LENUS (Irish Health Repository)

Lucey, S

2010-04-01

The effect of pre-heating resin composite on pre-cured viscosity and post-cured surface hardness was evaluated. Groups of uncured specimens were heated to 60 degrees C and compared with control groups (24 degrees C) with respect to viscosity and surface hardness. Mean (SD) viscosities of the pre-heated specimens (n = 15) were in the range of 285 (13)-377 (11) (Pa) compared with 642 (35)-800 (23) (Pa) at ambient temperature. There was a statistically significant difference between the two groups (P < 0.001). Mean (SD) Vickers microhardness (VHN) of the pre-heated group (n = 15) was 68.6 (2.3) for the top surface and 68.7 (1.8) for the bottom surface measured at 24 h post curing (specimen thickness = 1.5 mm). The corresponding values for the room temperature group were 60.6 (1.4) and 59.0 (3.5). There was a statistically significant difference between corresponding measurements taken at the top and bottom for the pre-heated and room temperature groups (P < 0.001). There was no significant difference between top and bottom measurements within each group. Pre-heating resin composite reduces its pre-cured viscosity and enhances its subsequent surface hardness. These effects may translate as easier placement together with an increased degree of polymerization and depth-of-cure.

Effect of heat treatment conditions on the passivation behavior of WE43C Mg–Y–Nd alloy in chloride containing alkaline environments

Directory of Open Access Journals (Sweden)

Jakraphan Ninlachart

2017-06-01

Full Text Available Mg–Y–Nd alloy (WE43C or Elektron 43 is a heat treatable magnesium wrought alloy that can be used up to 250 °C for aerospace application. This alloy has excellent mechanical properties (UTS: up to 345 MPa at room temperature and improved corrosion resistance. Electrochemical passivation studies were conducted on this alloy under different heat treatment conditions in 0.1 M NaOH solution with the addition of chloride from 0 to 1000 ppm. The passive potential range typically extended to more than 1.5 VAg/AgCl. The transpassive potential was not dependent on the heat treatment condition of the alloy when the chloride concentration increased up to 500 ppm. However, pitting protection potential varied with the heat treatment condition when the chloride addition was 500 ppm or more. The specimen surface was analyzed using scanning electron microscopy (SEM, X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS, and Raman spectroscopy to understand the passivation behavior of this alloy. The passivated surface of the WE43C specimens indicated that the surface layer consisted of MgO, Mg(OH2, and rare earth oxide phases, and the heat treatment conditions did not significantly affect the composition of the surface film.

Shelf-life extension of bread by heat and irradiation treatment [Bangladesh

International Nuclear Information System (INIS)

Begum, F.; Siddique, A.K.; Choudhury, N.; Mollah, R.A.

1994-01-01

Bread slices were given irradiation treatment 0.5, 1.0, 1.5, and 2.0 KGy and heat treatment at 60 deg. C for 20 min to control mould growth. Mould growth was reladed at ambient temperature by 3, 4, 6 and 8 days after 0.5, 1.0, 1.5 and 2.0 KGy treatments, respectively, compared to 2 days in case of control sample and 3 days for heat treatment alone. Combination of heat with irradiation at 0.5, 1.0, 1.5 and 2.0 KGy retarded mould growth up to 4, 6, 7 an 9 days, respectively. Organoleptically, the irradiated bread slices were acceptable up to 3 to 6 days depending on the treatment. The combination method treated slices were acceptable up to 8 days. The application of radiation dose exceeding 2.0 KGy caused off flavour. Mild heat treatment and radiation in combination resulted in a synergistic antifungal effect and enhanced shelf-life of bread

Estimate of thermoelastic heat production from superconducting composites in pulsed poloidal coil systems

International Nuclear Information System (INIS)

Ballou, J.K.; Gray, W.H.

1976-01-01

In the design of the cryogenic system and superconducting magnets for the poloidal field system in a tokamak, it is important to have an accurate estimate of the heat produced in superconducting magnets as a result of rapidly changing magnetic fields. A computer code, PLASS (Pulsed Losses in Axisymmetric Superconducting Solenoids), was written to estimate the contributions to the heat production from superconductor hysteresis losses, superconductor coupling losses, stabilizing material eddy current losses, and structural material eddy current losses. Recently, it has been shown that thermoelastic dissipation in superconducting composites can contribute as much to heat production as the other loss mechanisms mentioned above. A modification of PLASS which takes into consideration thermoelastic dissipation in superconducting composites is discussed. A comparison between superconductor thermoelastic dissipation and the other superconductor loss mechanisms is presented in terms of the poloidal coil system of the ORNL Experimental Power Reactor design

Influence of heat treatment on structure and some physical properties of lithium boro-niobate glass

Science.gov (United States)

Kashif, I.; Sakr, E. M.; Soliman, A. A.; Ratep, A.

2012-08-01

The glass composition (90 mol% Li2B4O7-10 mol% Nb2O5) was prepared by the melt quenching technique. The quenched sample was heat treated at 480°C, 545°C and 630°C for 5 h and heat treated at 780°C with different time. The times were 5, 10, 15, 20, 28, and 36 h. The glass and glass ceramics were studied by differential thermal analysis (DTA), X-ray diffraction (XRD), and dc conductivity as a function of temperature. Lithium niobate (LiNbO3) and lithium diborate (Li2B4O7) were the main phases in glass ceramic addition to traces from LiNb3O8. Crystallite size of the main phases determined from the X-ray diffraction peaks are in the range <100 nm. The fraction of crystalline (LiNbO3) phase increases with increase the heat treatment temperature and time. The relation between physical properties and structure were studied.

Review of thermo-physical properties, wetting and heat transfer characteristics of nanofluids and their applicability in industrial quench heat treatment.

Science.gov (United States)

Ramesh, Gopalan; Prabhu, Narayan Kotekar

2011-04-14

The success of quenching process during industrial heat treatment mainly depends on the heat transfer characteristics of the quenching medium. In the case of quenching, the scope for redesigning the system or operational parameters for enhancing the heat transfer is very much limited and the emphasis should be on designing quench media with enhanced heat transfer characteristics. Recent studies on nanofluids have shown that these fluids offer improved wetting and heat transfer characteristics. Further water-based nanofluids are environment friendly as compared to mineral oil quench media. These potential advantages have led to the development of nanofluid-based quench media for heat treatment practices. In this article, thermo-physical properties, wetting and boiling heat transfer characteristics of nanofluids are reviewed and discussed. The unique thermal and heat transfer characteristics of nanofluids would be extremely useful for exploiting them as quench media for industrial heat treatment.

Review of thermo-physical properties, wetting and heat transfer characteristics of nanofluids and their applicability in industrial quench heat treatment

Directory of Open Access Journals (Sweden)

Ramesh Gopalan

2011-01-01

Full Text Available Abstract The success of quenching process during industrial heat treatment mainly depends on the heat transfer characteristics of the quenching medium. In the case of quenching, the scope for redesigning the system or operational parameters for enhancing the heat transfer is very much limited and the emphasis should be on designing quench media with enhanced heat transfer characteristics. Recent studies on nanofluids have shown that these fluids offer improved wetting and heat transfer characteristics. Further water-based nanofluids are environment friendly as compared to mineral oil quench media. These potential advantages have led to the development of nanofluid-based quench media for heat treatment practices. In this article, thermo-physical properties, wetting and boiling heat transfer characteristics of nanofluids are reviewed and discussed. The unique thermal and heat transfer characteristics of nanofluids would be extremely useful for exploiting them as quench media for industrial heat treatment.

Isothermal heat treatment influence on the interface of a powder metallurgy aluminium metal matrix composite reinforced with Ni3Al intermetallics

International Nuclear Information System (INIS)

Ferrer, C.; Amigo, V.; Salvador, M.D.; Busquets, D.; Torralba, J.M.

1998-01-01

The improvement of the mechanical properties of aluminium MMCs reinforced with Ni 3 Al particles is based on the continuity of the matrix-particle interface as well as on the strength of these particles. This work deals with the influence of different heat treatments on the evolution of new phases in that interface. Samples were prepared following a powder metallurgy route with a final stage of extrusion. Several heat treatments encompassing a broad group of temperatures and times were applied producing different phases around the primary particles. Samples were analysed via optical and scanning electron microscopy with energy dispersive X ray analysis. Microhardness tests were also conducted on the different phases generated. (Author) 15 refs

Milk protein-gum tragacanth mixed gels: effect of heat-treatment sequence.

Science.gov (United States)

Hatami, Masoud; Nejatian, Mohammad; Mohammadifar, Mohammad Amin; Pourmand, Hanieh

2014-01-30

The aim of this study was to investigate the role of the heat-treatment sequence of biopolymer mixtures as a formulation parameter on the acid-induced gelation of tri-polymeric systems composed of sodium caseinate (Na-caseinate), whey protein concentrate (WPC), and gum tragacanth (GT). This was studied by applying four sequences of heat treatment: (A) co-heating all three biopolymers; (B) heating the milk-protein dispersion and the GT dispersion separately; (C) heating the dispersion containing Na-caseinate and GT together and heating whey protein alone; and (D) co-heating whey protein with GT and heating Na-caseinate alone. According to small-deformation rheological measurements, the strength of the mixed-gel network decreased in the order: C>B>D>A samples. SEM micrographs show that the network of sample C is much more homogenous, coarse and dense than sample A, while the networks of samples B and D are of intermediate density. The heat-treatment sequence of the biopolymer mixtures as a formulation parameter thus offers an opportunity to control the microstructure and rheological properties of mixed gels. Copyright © 2013 Elsevier Ltd. All rights reserved.

Influence of heat treatment conditions on structure and corrosion fracture of welded joints of zirconium alloy with 2.5 % niobium in agressive media

International Nuclear Information System (INIS)

Goncharov, A.B.; Nerodenko, M.M.; Tkachenko, L.M.; Adeeva, L.I.

1990-01-01

Influence of heat treatment on corrosion resistance of Zr-2.5 % Nb alloy welded joints is studied. It is stated that alloy after annealing in β-region has maximum corrosion resistance in sulfuric acid. Corrosion resistance in acetic acid doesn't depend on heat treatment. The best operating characteristics in steam-water medium of high parameters have welded joints, structure and phase composition of which approach α-phase with fine-dispersed β Nb particles, uniformly distributed in grain matrix. Such structure is attained by annealing in α-region or quenching with the following annealing at 850 K

Influence of composition, heat treatment and neutron irradiation on the electrical conductivity of copper alloys

Science.gov (United States)

Eldrup, M.; Singh, B. N.

1998-10-01

The electrical conductivity of three different types of copper alloys, viz. CuNiBe, CuCrZr and Cu-Al 2O 3 as well as of pure copper are reported. The alloys have undergone different pre-irradiation heat treatments and have been fission-neutron irradiated up to 0.3 dpa. In some cases post-irradiation annealing has been carried out. The results are discussed with reference to equivalent Transmission Electron Microscopy results on the microstructure of the materials. The CuNiBe has the lowest conductivity (⩽55% of that of pure Cu), and Cu-Al 2O 3 the highest (75-90% of pure Cu).

Computational study of fluid flow and heat transfer in composite packed beds of spheres with low tube to particle diameter ratio

International Nuclear Information System (INIS)

Yang, Jian; Wu, Jiangquan; Zhou, Lang; Wang, Qiuwang

2016-01-01

Highlights: • Flow and heat transfer in composite packed beds with low d_t/d_p_e are investigated. • The wall effect would be restrained with radially layered composite packing (RLM). • Heat flux and overall heat transfer efficiency can be improved with RLM packing. - Abstract: The effect of the tube wall on the fluid flow and heat transfer would be important in the packed bed with low tube to particle diameter ratio, which may lead to flow and temperature maldistributions inside, and the heat transfer performance may be lowered. In the present paper, the flow and heat transfer performances in both the composite and uniform packed beds of spheres with low tube to particle diameter were numerically investigated, where the composite packing means randomly packing with non-uniform spheres and the uniform packing means randomly packing with uniform spheres, including radially layered composite packing (RLM), axially layered composite packing (ALM), randomly composite packing (RCM) and randomly uniform packing (RPM). Both the composite and uniform packings were generated with discrete element method (DEM), and the influence of the wall effect on the flow and heat transfer in the packed beds were carefully studied and compared with each other. Firstly, it is found that, the wall effect on the velocity and temperature distributions in the randomly packed bed of uniform spheres (RPM) with low tube to particle diameter ratio were obvious. The average velocity of the near-tube-wall region is higher than that of the inner-tube region in the bed. When the tube wall is adiabatic, the average temperature of the near-tube-wall region is lower. With radially layered composite packing method (RLM), smaller pores would be formed close to the tube wall and big flow channels would be formed in the inner-tube region of the bed, which would be benefit to restrain the wall effect and improve heat transfer in the bed with low tube to particle diameter ratio. Furthermore, it is also

Computational study of fluid flow and heat transfer in composite packed beds of spheres with low tube to particle diameter ratio

Energy Technology Data Exchange (ETDEWEB)

Yang, Jian, E-mail: yangjian81@mail.xjtu.edu.cn [Key Laboratory of Thermo-Fluid Science and Engineering, Ministry of Education, School of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China); Wu, Jiangquan [CSR Research of Electrical Technology and Material Engineering, Zhuzhou, Hunan 412001 (China); Zhou, Lang; Wang, Qiuwang [Key Laboratory of Thermo-Fluid Science and Engineering, Ministry of Education, School of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China)

2016-04-15

Highlights: • Flow and heat transfer in composite packed beds with low d{sub t}/d{sub pe} are investigated. • The wall effect would be restrained with radially layered composite packing (RLM). • Heat flux and overall heat transfer efficiency can be improved with RLM packing. - Abstract: The effect of the tube wall on the fluid flow and heat transfer would be important in the packed bed with low tube to particle diameter ratio, which may lead to flow and temperature maldistributions inside, and the heat transfer performance may be lowered. In the present paper, the flow and heat transfer performances in both the composite and uniform packed beds of spheres with low tube to particle diameter were numerically investigated, where the composite packing means randomly packing with non-uniform spheres and the uniform packing means randomly packing with uniform spheres, including radially layered composite packing (RLM), axially layered composite packing (ALM), randomly composite packing (RCM) and randomly uniform packing (RPM). Both the composite and uniform packings were generated with discrete element method (DEM), and the influence of the wall effect on the flow and heat transfer in the packed beds were carefully studied and compared with each other. Firstly, it is found that, the wall effect on the velocity and temperature distributions in the randomly packed bed of uniform spheres (RPM) with low tube to particle diameter ratio were obvious. The average velocity of the near-tube-wall region is higher than that of the inner-tube region in the bed. When the tube wall is adiabatic, the average temperature of the near-tube-wall region is lower. With radially layered composite packing method (RLM), smaller pores would be formed close to the tube wall and big flow channels would be formed in the inner-tube region of the bed, which would be benefit to restrain the wall effect and improve heat transfer in the bed with low tube to particle diameter ratio. Furthermore, it

Effect of supplementary glycerin on milk composition and heat stability in dairy goats

Directory of Open Access Journals (Sweden)

Deela Thoh

2017-12-01

Full Text Available Objective This experiment was studied the effects of various levels of crude glycerin (CG in dairy goat diet on daily intake, milk yield, milk composition, some physical properties and some quality changes of goat milk after sterilization. Methods Twelve 75% Saanen dairy goats (body weight = 49±3 kg; days in milk = 60±12 d were randomly assigned in a completely randomized design to evaluate the effects of three experimental diets consisting of 0%, 5%, and 10% CG (dry matter basis which were formulated to meet or exceed the nutrient requirements of goats. Experimental dairy goats were evaluated for feed and milk yield. Milk samples were analyzed for their composition, including fatty acids, casein profile, fat globule size, and color, and were sterilized to evaluate milk heat stability. Results There were no significant differences between 0% and 5% CG treatments infeed. Increasing CG supplementation from 0% to 5% increased milk yield from 2.38±0.12 to 2.64±0.23 kg/goat/d. In addition, milk samples from 5% CG treatment had the highest total solids, fat content and lactose content, and largest fat globule size. Increasing CG to 10% resulted in a decrease in milk fat. After sterilizing at 116°C, F0 = 3 min, goat milk samples from 5% CG treatment had slightly higher sediment content and comparatively higher degree of browning. Conclusion Considering milk yield, milk fat content and quality of sterilized milk, 5% CG supplementation in a total mixed ration has a potential for implementation in dairy goats.

Making use of guava seed (Psidium guajava L): the effects of pre-treatments on its chemical composition.

Science.gov (United States)

Chang, Ying Ping; Tan, May Ping; Lok, Wai Li; Pakianathan, Suganthi; Supramaniam, Yasoga

2014-03-01

The guava processing industry in Malaysia produces by-products in the form of seed core and peel. These by-products can be regarded as underused resources but there are concerns about their composition that prevent their use in the food and feed industries. This study aims to analyze the respective effects of heat treatments (boiling or autoclaving) and germination periods on the nutritional composition and phytochemical content of guava seeds. The guava seeds were found to contain 618, 78, 72, and 5 mg/g dry weight total dietary fiber, fat, protein, and ash, respectively. The tannin and saponin contents, but not the phytic acid content, were below the respective anti-nutritional thresholds. The heat treatments did not affect the total dietary fiber and ash contents but reduced all other chemical components to different extents (15-91%). Boiling did not reduce the phytic acid content substantially but autoclaving caused a reduction of 91% to a level below the anti-nutritional threshold. Germination for 14 days caused a significant reduction in nutrient contents in the range of 16-79%. Germination also reduced the phytic acid content by 90% in the seed but did not significantly affect the saponin content. Thus, guava seed can be treated thermally or germinated to manipulate its chemical composition to enable its use in the food and feed industries.

Heat Treatment of Gas-Atomized Powders for Cold Spray Deposition

Science.gov (United States)

Story, William A.; Brewer, Luke N.

2018-02-01

This communication demonstrates the efficacy of heat treatment on the improved deposition characteristics of aluminum alloy powders. A novel furnace was constructed for solutionizing of feedstock powders in an inert atmosphere while avoiding sintering. This furnace design achieved sufficiently high cooling rates to limit re-precipitation during powder cooling. Microscopy showed homogenization of the powder particle microstructures after heat treatment. Cold spray deposition efficiency with heat-treated powders substantially increased for the alloys AA2024, AA6061, and AA7075.

Influence of the cementitious paste composition on the E-modulus and heat of hydration evolutions

International Nuclear Information System (INIS)

Maia, Lino; Azenha, Miguel; Faria, Rui; Figueiras, Joaquim

2011-01-01

E-modulus and heat of hydration are features of cement-based materials that follow a rapid rate of change at early ages. This paper analyses the influence of the composition of cementitious pastes on these features by using two methods: (i) a novel technique for continuously monitoring the E-modulus of cement-based materials, based on evaluating the first resonant frequency of a composite beam containing the material under testing, and (ii) an isothermal calorimeter to determine the released heat of hydration. Seventeen mixes are tested, encompassing pastes with five w/c ratios, as well as different contents of limestone filler, fly ash, silica fume and metakaolin. The results permit the comparison of the E-modulus and heat of hydration sensitivities to mix composition changes, and to check possible relations between these features. This work also helps to establish the technique (i) as a non-destructive method for monitoring the E-modulus evolution in cement-based materials since casting.

Calculation and Designing of Up-to-Date Gas-Flame Plants for Metal Heating and Heat Treatment

Directory of Open Access Journals (Sweden)

V. I. Тimoshpolsky

2008-01-01

Full Text Available An analysis of development trends in the CIS machine-building industry and current status of the heating and heat treatment furnaces of main machine-building enterprises of the Republic of Belarus as of the 1st quarter of 2008 is given in the paper.The paper presents the most efficient engineering solutions from technological and economic point of view that concern calculation and designing of up-to-date gas-flame plants which are to be applied for modernization of the current heating and heat treatment furnaces of the machine-building enterprises in the Republic of Belarus.A thermo-technical calculation of main indices of the up-to-date gas-flame plant has been carried out in the paper.

Study of heat treatment parameters for large-scale hydraulic steel gate track

Directory of Open Access Journals (Sweden)

Ping-zhou Cao

2013-10-01

Full Text Available In order to enhance external hardness and strength, a large-scale hydraulic gate track should go through heat treatment. The current design method of hydraulic gate wheels and tracks is based on Hertz contact linear elastic theory, and does not take into account the changes in mechanical properties of materials caused by heat treatment. In this study, the heat treatment parameters were designed and analyzed according to the bearing mechanisms of the wheel and track. The quenching process of the track was simulated by the ANSYS program, and the temperature variation, residual stress, and deformation were obtained and analyzed. The metallurgical structure field after heat treatment was predicted by the method based on time-temperature-transformation (TTT curves. The results show that the analysis method and designed track heat treatment process are feasible, and can provide a reference for practical projects.

Evolution of microstructure and hardness of AE42 alloy after heat treatments

DEFF Research Database (Denmark)

Huang, Y.D.; Dieringa, H.; Hort, N.

2008-01-01

properties even further. It is shown that the microstructure of the squeeze-cast AE42 alloy is stable at high temperature 450 degrees C. The subsequent solution and ageing treatments have a limited effect on the hardness. The weak age-hardening is attributed to the precipitation of small amount Of Mg17Al12......The AE42 magnesium alloy was developed for high pressure die casting (HPDC) from low-aluminum magnesium alloys. In this alloy the rare earth (RE) elements were shown to increase creep resistance by forming AlxREy intermetallics along the grain boundaries. The present work investigates...... the microstructure of squeeze cast AE42 magnesium alloy and evaluates its hardness before and after heat treatments. The change in hardness is discussed based on the microstructural observations. Some suggestions are given concerning future design of alloy compositions in order to improve high temperature creep...

Irradiation in combination of heat treatment of mango puree

International Nuclear Information System (INIS)

Noomhorm, A.; Apintanapong, M.

1996-01-01

The effect of irradiation with heat combination treatment on the shelf life and quality of mango puree was studied. Thermal inactivation of polyphenol oxidase enzyme at 80 degree C and 15 min. was used as a measure of adequacy of pre-heat treatment. Irradiation of mango puree after heat treatment at dosage of 0, 2, 4, 6 and 8 kGy showed no change in mc, pH, acidity, and TSS but during storage, growth of microorganisms brought changes in these values. Irradiation in combination with low temperature (5 degree C) reduced discoloration and darkening rate during storage. Irradiation dose from 0 to 8 kGy resulted in log linear reductions in microorganism levels but at 6 and 8 kGy, there was no growth of microorganisms. Products irradiated at 8 kGy showed no microorganism growth at both temperatures

Preparation, Characterization and Thermal Properties of Paraffin Wax – Expanded Perlite Form-Stable Composites for Latent Heat Storage

Directory of Open Access Journals (Sweden)

Tugba GURMEN OZCELIK

2017-02-01

Full Text Available In this study, form-stable composite phase change materials (PCM for latent heat storage were prepared by impregnating paraffin wax into the pores of the expanded perlite (EP. The characterization of the composite PCMs was performed by FTIR, TGA, SEM and DSC analysis. The melting point and heat of fusion were determined for 25 % paraffin included composite, as 54.3 °C and 94.71 J/g and for 45 % paraffin included composite as 53.6 °C and 106.69 J/g, respectively. The FTIR results showed that there were no chemical reaction between the perlite and paraffin. TGA analysis indicated that both composite PCMs had good thermal stability. SEM images showed that the paraffin was dispersed uniformly into the pores and on the EP surface. There was no leakage and degradation at the composite PCMs after heating and cooling cycles. According to the results, both prepared composites showed good thermal energy storage properties, reliability and stability. All results suggested that the presented form- stable composite PCMs has great potential for thermal energy storage applications.DOI: http://dx.doi.org/10.5755/j01.ms.23.1.13661

Modeling Precipitation Kinetics During Heat Treatment with Calphad-Based Tools

Science.gov (United States)

Chen, Qing; Wu, Kaisheng; Sterner, Gustaf; Mason, Paul

2014-12-01

Sophisticated precipitation reaction models combined with well-developed CALPHAD databases provide an efficient way to tailor precipitate microstructures that maximize strengthening via the optimization of alloy chemistries and heat treatment schedules. The success of the CALPHAD approach relies on the capability to provide fundamental phase equilibrium and phase transformation information in materials of industrial relevance taking into consideration composition and temperature variation. The newly developed TC-PRISMA program is described. The effect of growth modes, alloy chemistries, and cooling profiles on the formation of multimodal microstructures has been examined in order to understand the underlying thermodynamics and kinetics. Practical issues that are critical to the accuracy and applicability of the current simulations, such as modifications that overcome mean field approximations, compatibility between CALPHAD databases, and selections of key parameters (particularly interfacial energy and nucleation site densities), are also addressed.

Ultrasonic evaluation of heat treatment for stress relief in steel

International Nuclear Information System (INIS)

Bittencourt, Marcelo de S.Q.; Lamy, Carlos A.; Goncalves Filho, Orlando J.A.; Payao Filho, Joao da C.

2000-01-01

Residual stresses in materials arise due to the manufacturing processes. As a consequence, in the nuclear area some components must suffer a stress relief treatment according to strict criteria. Although these treatments are carefully carried on, concern with nuclear safety is constantly growing. This work proposes a nondestructive ultrasonic method to guarantee the efficiency of the heat treatment. It was used a short peened steel plate with tensile and compressive stresses which was submitted to a stress relief treatment. The results show that the proposed ultrasonic method could be used to confirm the efficiency of the stress relief heat treatment. (author)

High performance carbon-carbon composites

Indian Academy of Sciences (India)

These composites are made of fibres in various directions and carbonaceous polymers and hydrocarbons as matrix precursors. Their density and properties depend on the type and volume fraction of reinforcement, matrix precursor used and end heat treatment temperature. Composites made with thermosetting resins as ...

Online Adaptive Hyperthermia Treatment Planning During Locoregional Heating to Suppress Treatment-Limiting Hot Spots.

Science.gov (United States)

Kok, H Petra; Korshuize-van Straten, Linda; Bakker, Akke; de Kroon-Oldenhof, Rianne; Geijsen, Elisabeth D; Stalpers, Lukas J A; Crezee, Johannes

2017-11-15

Adequate tumor temperatures during hyperthermia are essential for good clinical response, but excessive heating of normal tissue should be avoided. This makes locoregional heating using phased array systems technically challenging. Online application of hyperthermia treatment planning could help to improve the heating quality. The aim of this study was to evaluate the clinical benefit of online treatment planning during treatment of pelvic tumors heated with the AMC-8 locoregional hyperthermia system. For online adaptive hyperthermia treatment planning, a graphical user interface was developed. Electric fields were calculated in a preprocessing step using our in-house-developed finite-difference-based treatment planning system. This allows instant calculation of the temperature distribution for user-selected phase-amplitude settings during treatment and projection onto the patient's computed tomographic scan for online visualization. Online treatment planning was used for 14 treatment sessions in 8 patients to reduce the patients' reports of hot spots while maintaining the same level of tumor heating. The predicted decrease in hot spot temperature should be at least 0.5°C, and the tumor temperature should decrease less than 0.2°C. These predictions were compared with clinical data: patient feedback about the hot spot and temperature measurements in the tumor region. In total, 17 hot spot reports occurred during the 14 sessions, and the alternative settings predicted the hot spot temperature to decrease by at least 0.5°C, which was confirmed by the disappearance of all 17 hot spot reports. At the same time, the average tumor temperature was predicted to change on average -0.01°C (range, -0.19°C to 0.34°C). The measured tumor temperature change was on average only -0.02°C (range, -0.26°C to 0.31°C). In only 2 cases the temperature decrease was slightly larger than 0.2°C, but at most it was 0.26°C. Online application of hyperthermia treatment planning is

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

Directory of Open Access Journals (Sweden)

Ming Li

2017-01-01

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

Influence of composition, heat treatment and neutron irradiation on the electrical conductivity of copper alloys

DEFF Research Database (Denmark)

Eldrup, Morten Mostgaard; Singh, B.N.

1998-01-01

The electrical conductivity of three different types of copper alloys, viz. CuNiBe, CuCrZr and Cu-Al(2)O(3) as well as of pure copper are reported. The alloys have undergone different pre-irradiation heat treatments and have been fission-neutron irradiated up to 0.3 dpa. In some cases post......-irradiation annealing has been carried out. The results are discussed with reference to equivalent Transmission Electron Microscopy results on the microstructure of the materials. The CuNiBe has the lowest conductivity (less than or equal to 55% of that of pure Cu), and Cu-Al(2)O(3) the highest (75-90% of pure Cu). (C...

Desensitization of stainless steels by laser surface heat-treatment

Energy Technology Data Exchange (ETDEWEB)

Nakao, Yoshikuni; Nishimoto, Kazutoshi

1987-11-01

Laser heating was applied for the desensitization heat-treatment of the surface layer in the sensitized HAZ of Type 304 stainless steel. The degree of sensitization was examined by EPR technique and the 10 % oxalic acid electrolytic etch test. The CO/sub 2/ laser with maximum power of 1.5 kW was used for heat-treatment. Time-Temperature-Desensitization diagram (TTDS diagram) for sensitized Type 304 stainless steels were developed by calculation assuming the chromium diffusion control for desensitization which might occur when the chromium depleted zone was healed up due to dissolution of chromium carbide and chromium diffusion from the matrix being heated at the solution annealing temperatures. TTDS diagrams calculated agree fairly well with ones determined by corrosion tests. Laser irradiation conditions (e.g., Laser power, beam diameter and traveling velocity) required for desensitization of sensitized Type 304 stainless steels were calculated using additivity rule from the TTDS diagram calculated and theoretical thermal curve of laser heating derived from the heat conduction theory. After laser beam irradiated under an optimum condition predicted by calculation, the sensitized HAZ of Type 304 stainless steel restored complete resistance to intergranular corrosion.

Online Adaptive Hyperthermia Treatment Planning During Locoregional Heating to Suppress Treatment-Limiting Hot Spots

NARCIS (Netherlands)

Kok, H. Petra; Korshuize-van Straten, Linda; Bakker, Akke; de Kroon-Oldenhof, Rianne; Geijsen, Elisabeth D.; Stalpers, Lukas J. A.; Crezee, Johannes

2017-01-01

Adequate tumor temperatures during hyperthermia are essential for good clinical response, but excessive heating of normal tissue should be avoided. This makes locoregional heating using phased array systems technically challenging. Online application of hyperthermia treatment planning could help to

Heat capacity of the white pine biocarbon preform and the related biocarbon/copper composite

Science.gov (United States)

Smirnov, I. A.; Orlova, T. S.; Smirnov, B. I.; Wlosewicz, D. W.; Misiorek, H.; Jezowski, A.; Wilkes, T. E.; Faber, K. T.

2009-11-01

This paper reports on measurements in the 80-300-K temperature interval of the heat capacity at constant pressure C p ( T) of high-porosity amorphous white pine carbon preforms (biocarbon) prepared by pyrolysis (carbonization) at T carb = 1000 and 2400°C in an argon flow. The dependences C p ( T) for biocarbon/copper composites based on the carbon preforms obtained have also been determined. It is shown that the mixture rule holds for the composites, i.e., that C p ( T) of the composite is a sum of the heat capacities of the constituent materials taken in the corresponding ratios. Phonon mean free paths for the white pine carbon preforms prepared at T carb = 1000 and 2400°C have been calculated and used to estimate the size of the nanocrystallites contributing to formation of the carbon frameworks of these preforms.

Development of electrically heated rods with resistive element of graphite or carbon/carbon composites for simulating transients in nuclear reactors

International Nuclear Information System (INIS)

Polidoro, H.A.

1987-01-01

Thermo-hydraulic problems, in nuclear plants are normally analysed by the use of electrically heated rods. The direct or indirect heater rods are limited in their use because, for high temperatures and high heat flux, the heating element temperature approach its melting point. The use of platinum or tantalum is not economically viable. Graphite and carbon/carbon composites are alternative materials because they are good electrical conductors and have good mechanical properties at high temperatures. Graphite and carbon/carbon composites were used to make heating elements for testing by indirect heating. The swaging process used to reduce the cladding diameter prevented the fabrication of graphite heater rods. Carbon/carbon composite used to make heating elements gave good results up to a heat flux of 100 W/cm 2 . It is easy to verify that this value can be exceeded if the choice of the complementary materials for insulator and cladding improved. (author) [pt

Method and apparatus for real-time measurement of fuel gas compositions and heating values

Science.gov (United States)

Zelepouga, Serguei; Pratapas, John M.; Saveliev, Alexei V.; Jangale, Vilas V.

2016-03-22

An exemplary embodiment can be an apparatus for real-time, in situ measurement of gas compositions and heating values. The apparatus includes a near infrared sensor for measuring concentrations of hydrocarbons and carbon dioxide, a mid infrared sensor for measuring concentrations of carbon monoxide and a semiconductor based sensor for measuring concentrations of hydrogen gas. A data processor having a computer program for reducing the effects of cross-sensitivities of the sensors to components other than target components of the sensors is also included. Also provided are corresponding or associated methods for real-time, in situ determination of a composition and heating value of a fuel gas.

Self-folding origami: shape memory composites activated by uniform heating

International Nuclear Information System (INIS)

Tolley, Michael T; Felton, Samuel M; Aukes, Daniel; Wood, Robert J; Miyashita, Shuhei; Rus, Daniela

2014-01-01

Self-folding is an approach used frequently in nature for the efficient fabrication of structures, but is seldom used in engineered systems. Here, self-folding origami are presented, which consist of shape memory composites that are activated with uniform heating in an oven. These composites are rapidly fabricated using inexpensive materials and tools. The folding mechanism based on the in-plane contraction of a sheet of shape memory polymer is modeled, and parameters for the design of composites that self-fold into target shapes are characterized. Four self-folding shapes are demonstrated: a cube, an icosahedron, a flower, and a Miura pattern; each of which is activated in an oven in less than 4 min. Self-sealing is also investigated using hot melt adhesive, and the resulting structures are found to bear up to twice the load of unsealed structures. (paper)

A Study of Ballast Water Treatment Using Engine Waste Heat

Science.gov (United States)

Balaji, Rajoo; Yaakob, Omar; Koh, Kho King; Adnan, Faizul Amri bin; Ismail, Nasrudin bin; Ahmad, Badruzzaman bin; Ismail, Mohd Arif bin

2018-05-01

Heat treatment of ballast water using engine waste heat can be an advantageous option complementing any proven technology. A treatment system was envisaged based on the ballast system of an existing, operational crude carrier. It was found that the available waste heat could raise the temperatures by 25 °C and voyage time requirements were found to be considerable between 7 and 12 days to heat the high volumes of ballast water. Further, a heat recovery of 14-33% of input energies from exhaust gases was recorded while using a test rig arrangement representing a shipboard arrangement. With laboratory level tests at temperature ranges of around 55-75 °C, almost complete species mortalities for representative phytoplankton, zooplankton and bacteria were observed while the time for exposure varied from 15 to 60 s. Based on the heat availability analyses for harvesting heat from the engine exhaust gases(vessel and test rig), heat exchanger designs were developed and optimized using Lagrangian method applying Bell-Delaware approaches. Heat exchanger designs were developed to suit test rig engines also. Based on these designs, heat exchanger and other equipment were procured and erected. The species' mortalities were tested in this mini-scale arrangement resembling the shipboard arrangement. The mortalities realized were > 95% with heat from jacket fresh water and exhaust gases alone. The viability of the system was thus validated.

Functional Properties of Glutinous Rice Flour by Dry-Heat Treatment.

Directory of Open Access Journals (Sweden)

Yang Qin

Full Text Available Glutinous rice flour (GRF and glutinous rice starch (GRS were modified by dry-heat treatment and their rheological, thermal properties and freeze-thaw stability were evaluated. Compared with the native GRF and GRS, the water-holding ability of modified GRF and GRS were enhanced. Both the onset and peak temperatures of the modified samples increased while the endothermic enthalpy change decreased significantly (p < 0.05. Meanwhile, dry heating remarkably increased the apparent viscosities of both GRF and GRS. Importantly, compared with GRS samples, the storage modulus (G' and loss modulus (G" values of modified GRF increased more greatly and the tanδ values decreased more remarkably, indicating that the dry-heat treatment showed more impact on the GRF and a higher viscoelasticity compared with GRS. Our results suggest the dry-heat treatment of GRF is a more effective method than that of GRS, which omits the complex and tedious process for purifying GRS, and thereby has more practical applications in the food industry.

Functional Properties of Glutinous Rice Flour by Dry-Heat Treatment.

Science.gov (United States)

Qin, Yang; Liu, Chengzhen; Jiang, Suisui; Cao, Jinmiao; Xiong, Liu; Sun, Qingjie

2016-01-01

Glutinous rice flour (GRF) and glutinous rice starch (GRS) were modified by dry-heat treatment and their rheological, thermal properties and freeze-thaw stability were evaluated. Compared with the native GRF and GRS, the water-holding ability of modified GRF and GRS were enhanced. Both the onset and peak temperatures of the modified samples increased while the endothermic enthalpy change decreased significantly (p < 0.05). Meanwhile, dry heating remarkably increased the apparent viscosities of both GRF and GRS. Importantly, compared with GRS samples, the storage modulus (G') and loss modulus (G") values of modified GRF increased more greatly and the tanδ values decreased more remarkably, indicating that the dry-heat treatment showed more impact on the GRF and a higher viscoelasticity compared with GRS. Our results suggest the dry-heat treatment of GRF is a more effective method than that of GRS, which omits the complex and tedious process for purifying GRS, and thereby has more practical applications in the food industry.

Simulation of Distortion and Residual Stress Development During Heat Treatment of Steel Castings

Energy Technology Data Exchange (ETDEWEB)

Beckermann, Christoph; Carlson, Kent

2011-07-22

Heat treatment and associated processing, such as quenching, are critical during high strength steel casting production. These processes must be managed closely to prevent thermal and residual stresses that may result in distortion, cracking (particularly after machining), re-work, and weld repair. The risk of casting distortion limits aggressive quenching that can be beneficial to the process and yield an improved outcome. As a result of these distortions, adjustments must be made to the casting or pattern design, or tie bars must be added. Straightening castings after heat treatments can be both time-consuming and expensive. Residual stresses may reduce a casting's overall service performance, possibly resulting in catastrophic failure. Stress relieving may help, but expends additional energy in the process. Casting software is very limited in predicting distortions during heat treatment, so corrective measures most often involve a tedious trial-and-error procedure. An extensive review of existing heat treatment residual stress and distortion modeling revealed that it is vital to predict the phase transformations and microstructure of the steel along with the thermal stress development during heat treatment. After reviewing the state-of-the-art in heat treatment residual stress and distortion modeling, an existing commercial code was selected because of its advanced capabilities in predicting phase transformations, the evolving microstructure and related properties along with thermal stress development during heat treatment. However, this software was developed for small parts created from forgings or machined stock, and not for steel castings. Therefore, its predictive capabilities for heat treatment of steel castings were investigated. Available experimental steel casting heat treatment data was determined to be of insufficient detail and breadth, and so new heat treatment experiments were designed and performed, casting and heat treating modified versions

Industrial heat treatment of R-HPDC A356 automotive brake callipers

CSIR Research Space (South Africa)

Chauke, L

2012-10-01

Full Text Available Heat treatment of rheo-high pressure die cast (R-HPDC) A356 brake callipers has produced good mechanical properties on the laboratory scale. An industrial heat treatment is required to evaluate the applicability and conformance of the R-HPDC A356...

Improvement of high temperature fatigue lifetime in AZ91 magnesium alloy by heat treatment

International Nuclear Information System (INIS)

Mokhtarishirazabad, Mehdi; Azadi, Mohammad; Hossein Farrahi, Gholam; Winter, Gerhard; Eichlseder, Wilfred

2013-01-01

In the present paper, an improvement in high temperature fatigue properties of the AZ91 magnesium alloy with rare earth elements has been obtained by a typical heat treatment, denoted by T6. For this objective, out-of-phase thermo-mechanical fatigue, room temperature and high temperature low cycle fatigue tests are performed to compare lifetimes. Several rare earth elements are initially added to the AZ91 alloy during a gravity casting process in permanent molds. Also, the type of the heat treatment is examined. Results of specimens with only the solution (the T4 heat treatment) and the solution with the ageing process (the T6 heat treatment) are compared under isothermal fatigue loadings. Microstructural investigations are carried out, before and after fatigue experiments to demonstrate the heat treatment effect. Results showed that both low cycle fatigue and thermo-mechanical fatigue of the alloy at high temperatures increases tremendously after the T6 heat treatment. This behavior attributes to the variation of the ductility, which was a result of microstructural changes during the heat treatment and the varying temperature in fatigue tests

Improvement of high temperature fatigue lifetime in AZ91 magnesium alloy by heat treatment

Energy Technology Data Exchange (ETDEWEB)

Mokhtarishirazabad, Mehdi [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Azadi, Mohammad, E-mail: m_azadi@ip-co.com [Fatigue and Wear Workgroup, Irankhodro Powertrain Company (IPCO), Tehran (Iran, Islamic Republic of); Hossein Farrahi, Gholam [School of Mechanical Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Winter, Gerhard; Eichlseder, Wilfred [Chair of Mechanical Engineering, University of Leoben, Leoben (Austria)

2013-12-20

In the present paper, an improvement in high temperature fatigue properties of the AZ91 magnesium alloy with rare earth elements has been obtained by a typical heat treatment, denoted by T6. For this objective, out-of-phase thermo-mechanical fatigue, room temperature and high temperature low cycle fatigue tests are performed to compare lifetimes. Several rare earth elements are initially added to the AZ91 alloy during a gravity casting process in permanent molds. Also, the type of the heat treatment is examined. Results of specimens with only the solution (the T4 heat treatment) and the solution with the ageing process (the T6 heat treatment) are compared under isothermal fatigue loadings. Microstructural investigations are carried out, before and after fatigue experiments to demonstrate the heat treatment effect. Results showed that both low cycle fatigue and thermo-mechanical fatigue of the alloy at high temperatures increases tremendously after the T6 heat treatment. This behavior attributes to the variation of the ductility, which was a result of microstructural changes during the heat treatment and the varying temperature in fatigue tests.

Flexible composite material with phase change thermal storage

Science.gov (United States)

Buckley, Theresa M. (Inventor)

2001-01-01

A highly flexible composite material having a flexible matrix containing a phase change thermal storage material. The composite material can be made to heat or cool the body or to act as a thermal buffer to protect the wearer from changing environmental conditions. The composite may also include an external thermal insulation layer and/or an internal thermal control layer to regulate the rate of heat exchange between the composite and the skin of the wearer. Other embodiments of the PCM composite also provide 1) a path for evaporation or direct absorption of perspiration from the skin of the wearer for improved comfort and thermal control, 2) heat conductive pathways within the material for thermal equalization, 3) surface treatments for improved absorption or rejection of heat by the material, and 4) means for quickly regenerating the thermal storage capacity for reuse of the material. Applications of the composite materials are also described which take advantage of the composite's thermal characteristics. The examples described include a diver's wet suit, ski boot liners, thermal socks, ,gloves and a face mask for cold weather activities, and a metabolic heating or cooling blanket useful for treating hypothermia or fever patients in a medical setting and therapeutic heating or cooling orthopedic joint supports.

Heat treated 9 Cr-1 Mo steel material for high temperature application

Science.gov (United States)

Jablonski, Paul D.; Alman, David; Dogan, Omer; Holcomb, Gordon; Cowen, Christopher

2012-08-21

The invention relates to a composition and heat treatment for a high-temperature, titanium alloyed, 9 Cr-1 Mo steel exhibiting improved creep strength and oxidation resistance at service temperatures up to 650.degree. C. The novel combination of composition and heat treatment produces a heat treated material containing both large primary titanium carbides and small secondary titanium carbides. The primary titanium carbides contribute to creep strength while the secondary titanium carbides act to maintain a higher level of chromium in the finished steel for increased oxidation resistance, and strengthen the steel by impeding the movement of dislocations through the crystal structure. The heat treated material provides improved performance at comparable cost to commonly used high-temperature steels such as ASTM P91 and ASTM P92, and requires heat treatment consisting solely of austenization, rapid cooling, tempering, and final cooling, avoiding the need for any hot-working in the austenite temperature range.

The Influence of Heat Treatment and Quencing Media at Bronze 80% Cu–20% Sn toward Fatique Life

Directory of Open Access Journals (Sweden)

Anak Agung Istri Agung Sri Komaladewi

2012-11-01

Full Text Available Production of the Balinese gamelan product rest on molding process which then continued with forging process, adjustment,and finally the finishing process. But still often to make the failure from this material like. The material become brokebecause heavy thing with the user processing (playing gambelan with continuity in the long time. The broke that happenfrom the heavy thing by the continuety that is called fatigue. At this examination the things that will be up is how much theheat treatment influence and the cooler thing with the fatigue life through the Reversed Bending process. By to variated theheat treatment and cooler thing to Bronze mixture 80%Cu and 20%Sn. This examination to aim at knowing the heattreatment influence and cooler thing at the composition of Bronze 80%Cu and 20%Sn about the fatigue life.The makingprocess of this things made by copper solution and the white Tin with the composition are 80%Cu and 20%Sn by variatedheat treatment and cooler media. The produce of this solution will print with the Reversed Bending speciment. Then thespeciment gift the heat treatment about 6500 C, 7000 C till 7500 C, and then the speciment keep cold by the water, oil and theair. The thing will be analize from the breach counture, Macro Structure and Micro Structure.The examination produceshowing the growing up at the fatigue life in the Bronze mixture 80%Cu - 20%Sn, From the heat treatment 6500 C, 7000 Cand 7500 C and become the drop age fatigue with the water cooler media with the age fatigue abaut 36621 cycle, and thefatigue by oil about 44975 cycle and the air cooler age fatigue about 55191 cycle. The inspection makro structure thebreach face colouring litle bit dark and the inspection mikro structure, the metal structure lool more bright.

Effect of Heat Treatment on Machining Properties of the AlSi9Cu3(Fe Alloy

Directory of Open Access Journals (Sweden)

Wieroński P.

2016-09-01

Full Text Available Automation of machining operations, being result of mass volume production of components, imposes more restrictive requirements concerning mechanical properties of starting materials, inclusive of machinability mainly. In stage of preparation of material, the machinability is influenced by such factors as chemical composition, structure, mechanical properties, plastic working and heat treatment, as well as a factors present during machining operations, as machining type, cutting parameters, material and geometry of cutting tools, stiffness of the system: workpiece – machine tool – fixture and cutting tool.

Gas injection to inhibit migration during an in situ heat treatment process

Science.gov (United States)

Kuhlman, Myron Ira; Vinegar; Harold J.; Baker, Ralph Sterman; Heron, Goren

2010-11-30

Methods of treating a subsurface formation are described herein. Methods for treating a subsurface treatment area in a formation may include introducing a fluid into the formation from a plurality of wells offset from a treatment area of an in situ heat treatment process to inhibit outward migration of formation fluid from the in situ heat treatment process.

Simulations of Precipitate Microstructure Evolution during Heat Treatment

Science.gov (United States)

Wu, Kaisheng; Sterner, Gustaf; Chen, Qing; Jou, Herng-Jeng; Jeppsson, Johan; Bratberg, Johan; Engström, Anders; Mason, Paul

Precipitation, a major solid state phase transformation during heat treatment processes, has for more than one century been intensively employed to improve the strength and toughness of various high performance alloys. Recently, sophisticated precipitation reaction models, in assistance with well-developed CALPHAD databases, provide an efficient and cost-effective way to tailor precipitate microstructures that maximize the strengthening effect via the optimization of alloy chemistries and heat treatment schedules. In this presentation, we focus on simulating precipitate microstructure evolution in Nickel-base superalloys under arbitrary heat treatment conditions. The newly-developed TC-PRISMA program has been used for these simulations, with models refined especially for non-isothermal conditions. The effect of different cooling profiles on the formation of multimodal microstructures has been thoroughly examined in order to understand the underlying thermodynamics and kinetics. Meanwhile, validations against several experimental results have been carried out. Practical issues that are critical to the accuracy and applicability of the current simulations, such as modifications that overcome mean-field approximations, compatibility between CALPHAD databases, selection of key parameters (particularly interfacial energy and nucleation site densities), etc., are also addressed.

Heat treatment trials for ITER toroidal field coils

International Nuclear Information System (INIS)

Matsui, Kunihiro; Hemmi, Tsutomu; Koizumi, Norikiyo; Nakajima, Hideo; Kimura, Satoshi; Nakamoto, Kazunari

2012-01-01

Cable-in-conduit (CIC) conductors using Nb 3 Sn strands are used in ITER toroidal fields (TF) coils. Heat treatment generates thermal strain in CIC conductors because of the difference in thermal expansion between the Nb 3 Sn strands and the stainless-steel jacket. The elongation/shrinkage of the TF conductor may make it impossible to insert a wound TF conductor into the groove of a radial plate. In addition, it is expected that the deformation of the winding due to heat treatment-based release of the residual force in the jacket may also make it impossible to insert the winding in the groove, and that correcting the winding geometry to allow insertion of the winding may influence the superconducting performance of the TF conductor. The authors performed several trials using heat treatment as the part of activities in Phase II of TF coil procurement aiming to resolve the above-mentioned technical issues, and evaluated the elongations of 0.064, 0.074 and 0.072% for the straight and curved conductors and 1/3-scale double-pancake (DP) winding, respectively. It was confirmed that correction if the deformed winding did not influence the superconducting performance of the conductor. (author)

Impact Toughness and Heat Treatment for Cast Aluminum

Science.gov (United States)

Lee, Jonathan A (Inventor)

2016-01-01

A method for transforming a cast component made of modified aluminum alloy by increasing the impact toughness coefficient using minimal heat and energy. The aluminum alloy is modified to contain 0.55%-0.60% magnesium, 0.10%-0.15% titanium or zirconium, less than 0.07% iron, a silicon-tomagnesium product ratio of 4.0, and less than 0.15% total impurities. The shortened heat treatment requires an initial heating at 1,000deg F. for up to I hour followed by a water quench and a second heating at 350deg F. to 390deg F. for up to I hour. An optional short bake paint cycle or powder coating process further increase.

Effect of heat treatment operations on the Rm tensile strength of silumins

Directory of Open Access Journals (Sweden)

J. Pezda

2010-10-01

Full Text Available Owing to good technological properties, low weight and good corrosion resistance, aluminum-silicon alloys are widely used as a material for cast machinery components. State of macro- and microstructure of a castings manufactured from Al-Si alloys, which is determined by a shape and distribution of hardening phases, segregation of alloying constituents and impurities, as well as distribution of porosity, create conditions to obtainment of proper mechanical properties. These properties can be improved through modification of the alloy and performed heat treatment operations. The paper presents effect of modification and heat treatment process on the Rm tensile strength of a selected silumins (EN AB-AlSi9Cu3(Fe, EN AB-AlSi12CuNiMg, EN AB-AlSi17Cu1Ni1Mg. Investigated alloys were put to treatments of refining and modification, and next to heat treatment. Temperature range of the heat treatment operations was determined on base of curves from the ATD method. Obtained results illustrate registered curves of melting and solidification from the ATD method and strength tests. On base of performed initial tests one determined parameters of the heat treatment process (temperature and duration of solutionig and ageing treatments enabling obtainment of improved Rm tensile strength of the investigated alloys.

Microwave heating for thermoplastic composites - Could the technology be used for welding applications?

Science.gov (United States)

Barasinski, Anaïs; Tertrais, Hermine; Bechtel, Stéphane; Chinesta, Francisco

2018-05-01

Welding primary structure thermoplastic composites parts is still an issue today, many technologies have been extensively studied: induction, ultrasonic, resistive welding, none is today entirely viable for this application due to various implementation reasons. On the other hand, microwave solutions are not very common in composites forming process, although being widespread in homes. Microwave (MW) technology relies on volumetric heating. Thermal energy is transferred from an electromagnetic field to materials that can absorb it at specific frequencies. Volumetric heating enables better process temperature control and less overall energy losses, which can results in shorter processing cycles and higher process efficiency. Nowadays, the main drawback of this technology is that the complex physics involved in the conversion of electromagnetic energy in thermal energy (heating) is not entirely understood and controlled for complex materials. In that work, the authors propose to look deeper in that way, first proposing a simulation tool, based on a coupling between a commercial code and a home made one, allowing the following of the electromagnetic field very precisely in the thickness of a laminate composite part, the last consisting of a stack of layers with different orientations, each layer made of a resin matrix and carbon fibers. Thermal fields are then computed and validated by experimental measurements. In a second part, the authors propose to look at a common welding case of a stringer, on a skin.

Exchange bias in sputtered FeNi/FeMn systems: Effect of short low-temperature heat treatments

Energy Technology Data Exchange (ETDEWEB)

Savin, Peter, E-mail: peter.savin@urfu.ru [Department of Magnetism and Magnetic Nanomaterials, Laboratory of Magnetic Sensors, Ural Federal University, 620002 Ekaterinburg (Russian Federation); Guzmán, Jorge [Instituto de Ciencia de Materiales de Madrid-CSIC, 28049 Madrid (Spain); Lepalovskij, Vladimir [Department of Magnetism and Magnetic Nanomaterials, Laboratory of Magnetic Sensors, Ural Federal University, 620002 Ekaterinburg (Russian Federation); Svalov, Andrey; Kurlyandskaya, Galina [Department of Magnetism and Magnetic Nanomaterials, Laboratory of Magnetic Sensors, Ural Federal University, 620002 Ekaterinburg (Russian Federation); Departamento de Electricidad y Electrónica, Universidad del País Vasco (UPV/EHU), 48940 Leioa, Vizcaya (Spain); Asenjo, Agustina [Instituto de Ciencia de Materiales de Madrid-CSIC, 28049 Madrid (Spain); Vas’kovskiy, Vladimir [Department of Magnetism and Magnetic Nanomaterials, Laboratory of Magnetic Sensors, Ural Federal University, 620002 Ekaterinburg (Russian Federation); Vazquez, Manuel [Department of Magnetism and Magnetic Nanomaterials, Laboratory of Magnetic Sensors, Ural Federal University, 620002 Ekaterinburg (Russian Federation); Instituto de Ciencia de Materiales de Madrid-CSIC, 28049 Madrid (Spain)

2016-03-15

Short (5 min) post-deposition thermal treatments under magnetic field at low temperature (up to 200 °C) performed in exchange-coupled FeNi(40 nm)/FeMn(20 nm) bilayer thin films prepared by magnetron sputtering are shown to be effective to significantly modify their exchange field (from around 40 Oe down to 27 Oe) between FeNi and FeMn layers. A similar exchange field decrease was observed for the first deposited FeNi layer of the FeNi(40 nm)/FeMn(20 nm)/FeNi(40 nm) trilayer films after the same thermal treatments. The exchange field value for the second FeNi layer was not substantially changed. The X-ray diffraction patterns indicates that such a heat treatment has no effect on the grain size and crystalline texture of the films, while atomic force microscope studies reveal an increase of the surface roughness after the treatment which is more noticeable in the case of the trilayer film. Analysis of the experimental results leads us to conclude that the variations of the exchange field after heat treatment are likely caused by a modification of interfacial roughness and/or interfacial magnetic structure, but unlikely by the changes in the microstructure and/or changes of composition of the antiferromagnetic FeMn layer. - Highlights: • FeNi/FeMn bilayers and FeNi/FeMn/FeNi trilayers were prepared by magnetron sputtering. • Post-deposition heat treatments at the temperatures below 200 °C during 5 min were made. • Annealing reduces the exchange field for the first FeNi layer in trilayers. • The exchange field value for the second FeNi layer was not substantially changed. • Exchange field changes are most likely caused by a modification of interface roughness.

A new paradigm for heat treatment of alloys

Energy Technology Data Exchange (ETDEWEB)

Ustinovshikov, Y., E-mail: ust@ftiudm.ru

2014-11-25

Highlights: • The sign of the ordering energy in alloys varies with the temperature. • Each temperature of heating leads to formation of its characteristic microstructure. • Quenching of alloys is a totally unnecessary and useless operation. - Abstract: The article considers the consequences in the field of heat treatment of alloys that could follow the introduction of the concept of phase transition ordering-phase separation into common use. By example of the Fe{sub 50}Cr{sub 50} alloy, industrial carbon tool steel and Ni{sub 88}Al{sub 12} alloy, it is shown that this transition occurs at a temperature, which is definite for each system, that the change of the sign of the chemical interaction between component atoms reverses the direction of diffusion fluxes in alloys, which affects changes in the type of microstructures. The discovery of this phase transition dramatically changes our understanding of the solid solution, changes the ideology of alloy heat treatment. It inevitably leads to the conclusion about the necessity of carrying out structural studies with the help of TEM in order to adjust the phase diagrams of the systems where this phase transition has been discovered. Conclusions have been made that quenching of alloys from the so-called region of the solid solution, which is usually performed before tempering (aging) is a completely unnecessary and useless operation, that the final structure of the alloy is formed during tempering (aging) no matter what the structure was before this heat treatment.

Study on Spheroidization and Related Heat Treatments of Medium Carbon Alloy Steels

Directory of Open Access Journals (Sweden)

Harisha S. R.

2018-01-01

Full Text Available The importance of medium carbon steels as engineering materials is reflected by the fact that out of the vast majority of engineering grade ferrous alloys available and used in the market today, a large proportion of them are from the family of medium carbon steels. Typically medium carbon steels have a carbon range of 0.25 to 0.65% by weight, and a manganese content ranging from 0.060 to 1.65% by weight. Medium carbon steels are more resistive to cutting, welding and forming as compared to low carbon steels. From the last two decades a number of research scholars reported the use of verity of heat treatments to tailor the properties of medium carbon steels. Spheroidizing is the novel industrial heat treatment employed to improve formability and machinability of medium/high carbon low alloy steels. This exclusive study covers procedure, the effects and possible outcomes of various heat treatments on medium carbon steels. In the present work, other related heat treatments like annealing and special treatments for property alterations which serve as pretreatments for spheroidizing are also reviewed. Medium carbon steels with property alterations by various heat treatment processes are finding increased responsiveness in transportation, aerospace, space, underwater along with other variegated fields. Improved tribological and mechanical properties consisting of impact resistance, stiffness, abrasion and strength are the main reasons for the increased attention of these steels in various industries. In the present scenario for the consolidation of important aspects of various heat treatments and effects on mechanical properties of medium carbons steel, a review of different research papers has been attempted. This review may be used as a guide to provide practical data for heat treatment industry, especially as a tool to enhance workability and tool life.

Enhancement of Thermoelectric Properties of PEDOT:PSS and Tellurium-PEDOT:PSS Hybrid Composites by Simple Chemical Treatment

Science.gov (United States)

Jin Bae, Eun; Hun Kang, Young; Jang, Kwang-Suk; Yun Cho, Song

2016-01-01

The thermoelectric properties of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and tellurium-PEDOT:PSS (Te-PEDOT:PSS) hybrid composites were enhanced via simple chemical treatment. The performance of thermoelectric materials is determined by their electrical conductivity, thermal conductivity, and Seebeck coefficient. Significant enhancement of the electrical conductivity of PEDOT:PSS and Te-PEDOT:PSS hybrid composites from 787.99 and 11.01 to 4839.92 and 334.68 S cm-1, respectively was achieved by simple chemical treatment with H2SO4. The power factor of the developed materials could be effectively tuned over a very wide range depending on the concentration of the H2SO4 solution used in the chemical treatment. The power factors of the developed thermoelectric materials were optimized to 51.85 and 284 μW m-1 K-2, respectively, which represent an increase of four orders of magnitude relative to the corresponding parameters of the untreated thermoelectric materials. Using the Te-PEDOT:PSS hybrid composites, a flexible thermoelectric generator that could be embedded in textiles was fabricated by a printing process. This thermoelectric array generates a thermoelectric voltage of 2 mV using human body heat.

Influence of heat treatment on magnesium alloys meant to automotive industry

NARCIS (Netherlands)

Popescu, G.; Moldovan, P.; Bojin, D.; Sillekens, W.H.

2009-01-01

The paper presents a study concerning the heat treatment realized on magnesium alloys, from AZ80 and ZK60 class. These alloys are destined to replace the conventional ferrous and aluminum alloys in automotive industry. It was realized the heat treatment, T5 - artificially aging, and it were

Experimental investigations on cylindrical latent heat storage units with sodium acetate trihydrate composites utilizing supercooling

DEFF Research Database (Denmark)

Dannemand, Mark; Johansen, Jakob Berg; Kong, Weiqiang

2016-01-01

Latent heat storage units utilizing stable supercooling of sodium acetate trihydrate (SAT) composites were tested in a laboratory. The stainless steel units were 1.5 m high cylinders with internal heat exchangers of tubes with fins. One unit was tested with 116 kg SAT with 6% extra water. Another...... in the thickened phase change material after melting. The heat content in the fully charged state and the heat released after solidification of the supercooled SAT mixtures at ambient temperature was higher for the unit with the thickened SAT mixture. The heat discharged after solidification of the supercooled SAT...

Enhancing composite durability : using thermal treatments

Science.gov (United States)

Jerrold E. Winandy; W. Ramsay Smith

2007-01-01

The use of thermal treatments to enhance the moisture resistance and aboveground durability of solid wood materials has been studied for years. Much work was done at the Forest Products Laboratory in the last 15 years on the fundamental process of both short-and long-term exposure to heat on wood materials and its interaction with various treatment chemicals. This work...

The effect of heat treatment on the magnitude and composition of residual gas in sealed silica glass ampoules

Science.gov (United States)

Palosz, W.; Szofran, F. R.; Lehoczky, S. L.

1994-01-01

The residual gas pressure and composition in sealed silica glass ampoules as a function of different treatment procedures has been investigated. The dependence of the residual gas on the outgassing and annealing parameters has been determined. The effects of the fused silica brand, of the ampoule fabrication, and of post-outgassing procedures have been evaluated.

Evaluation of carbon diffusion in heat treatment of H13 tool steel under different atmospheric conditions

Directory of Open Access Journals (Sweden)

Maziar Ramezani

2015-04-01

Full Text Available Although the cost of the heat treatment process is only a minor portion of the total production cost, it is arguably the most important and crucial stage on the determination of material quality. In the study of the carbon diffusion in H13 steel during austenitization, a series of heat treatment experiments had been conducted under different atmospheric conditions and length of treatment. Four austenitization atmospheric conditions were studied, i.e., heat treatment without atmospheric control, heat treatment with stainless steel foil wrapping, pack carburization heat treatment and vacuum heat treatment. The results showed that stainless steel foil wrapping could restrict decarburization process, resulting in a constant hardness profile as vacuum heat treatment does. However, the tempering characteristic between these two heat treatment methods is different. Results from the gas nitrided samples showed that the thickness and the hardness of the nitrided layer is independent of the carbon content in H13 steel.

Effects of heat treatment temperature on morphology and properties of opal crystal

International Nuclear Information System (INIS)

Duan Tao; China Academy of Engineering Physics, Mianyang; Peng Tongjiang; Chen Jiming; Tang Yongjian

2008-01-01

The monodispersed SiO 2 microspheres were synthesized by reactant mixed equally. The colloid crystal templates were assemblied by vertical sedimentation method in ethanol at certain temperatures, and the effects of the heat treatment temperature on the morphology and the properties of opal colloid crystals were investigated. SEM, TCr-DSC results indicate SiO 2 colloid templates should be heat treated at 700-800 degree C, enhancing the conglutination and mechanistic intensity of opal templates. UV-Vis analysis result indicates that the heat treatment process can remove the photonic band gap location of the opal colloid crystals, and with the heat treatment temperature increasing gradually, blue shift occurs and the gap narrows. (authors)

Heat treatment effect on ductility of nickel-base alloys

International Nuclear Information System (INIS)

Burnakov, K.K.; Khasin, G.A.; Danilov, V.F.; Oshchepkov, B.V.; Listkova, A.I.

1979-01-01

Causes of low ductility of the KhN75MBTYu and KhN78T alloys were studied along with the heat treatment effects. Samples were tested at 20, 900, 1100, 1200 deg C. Large amount of inclusions was found in intercrystalline fractures of the above low-ductile alloys. The inclusions of two types took place: (α-Al 2 O 3 , FeO(Cr 2 O 3 xAl 2 O 3 )) dendrite-like ones and large-size laminated SiO 2 , FeO,(CrFe) 2 O 3 inclusions situated as separate colonies. Heat treatment of the alloys does not increase high-temperature impact strength and steel ductility. The heating above 1000 deg C leads to a partial dissolution and coagulation of film inclusions which results in an impact strength increase at room temperature

Heat Treatment of Cr- and Cr-V ledeburitic tool steels

Directory of Open Access Journals (Sweden)

Peter Jurči

2014-11-01

Full Text Available Cr- and Cr-V ledeburitic cold work tool steels belong to the most important tool materials for large series manufacturing. To enable high production stability, the tools must be heat treated before use. This overview paper brings a comprehensive study on the heat treatment of these materials, starting from the soft annealing and finishing with the tempering. Also, it describes the impact of any step of the heat treatment on the most important structural and mechanical characteristics, like the hardness, the toughness and the wear resistance. The widely used AIS D2- steel (conventionally manufactured and Vanadis 6 (PM are used as examples in most cases.

Dimensional Behavior of Matrix Graphite Compacts during Heat Treatments for HTGR Fuel Element Fabrication

International Nuclear Information System (INIS)

Lee, Young-Woo; Yeo, Seunghwan; Cho, Moon Sung

2015-01-01

The carbonization is a process step where the binder that is incorporated during the matrix graphite powder preparation step is evaporated and the residue of the binder is carbonized during the heat treatment at about 1073 K. This carbonization step is followed by the final high temperature heat treatment where the carbonized compacts are heat treated at 2073-2173 K in vacuum for a relatively short time (about 2 hrs). In order to develop a fuel compact fabrication technology, and for fuel matrix graphite to meet the required material properties, it is essential to investigate the relationship among the process parameters of the matrix graphite powder preparation, the fabrication parameters of fuel element green compact and the heat treatments conditions, which has a strong influence on the further steps and the material properties of fuel element. In this work, the dimensional changes of green compacts during the carbonization and final heat treatment are evaluated when compacts have different densities from different pressing conditions and different final heat treatment temperatures are employed, keeping other process parameters constant, such as the binder content, carbonization time, temperature and atmosphere (two hours ant 1073K and N2 atmosphere). In this work, the dimensional variations of green compacts during the carbonization and final heat treatment are evaluated when compacts have different densities from different pressing conditions and different final heat treatment temperatures are employed

Stone heat treatment in the Early Mesolithic of southwestern Germany: Interpretation and identification.

Directory of Open Access Journals (Sweden)

Patrick Schmidt

Full Text Available The Early Mesolithic of southwestern Germany, the so-called Beuronian (9600-7100 BC, is a period of important transformations in the way people lived, in their subsistence and in the stone tools they produced. One of the perhaps most spectacular re-inventions of that time is heat treatment of stones prior to their manufacture into tools. Although heat treatment has been understood as one of the defining characteristics of the Beuronian of southwestern Germany, and although its existence has been known for almost 30 years now, relatively few systematic studies on it are available. In this paper, we present such a study, aiming to shed light on two questions: (1 what technique and heating parameters were used in the Beuronian and (2 how reliable are the macroscopic proxies traditionally used to identify heat treatment in this context? We investigate these questions using a non-destructive archaeometric technique for measuring past heating temperatures of heat-treated stones and a quantitative surface roughness analysis aiming to understand the relations between surface aspect and heat treatment. These methods are applied to 46 Jurassic chert artefacts from the site Helga-Abri located in the Swabian Alb region of southwestern Germany. Our results document that an opportunistic low-investment procedure was used to heat stone, probably relying on the use of the above-ground part of regular camp-fires. We also found that the traditionally used macroscopic criteria, such as colour and surface gloss, cannot be unambiguously used to identify heat treatment in assemblages made from Jurassic chert. These findings have important implications for our understanding of the Beuronian lithic chaîne opératoire in terms of the investment in time and resources necessary, and for the refinement of archaeological techniques used to identify heat treatment in the Mesolithic of the Swabian Alb.

Stone heat treatment in the Early Mesolithic of southwestern Germany: Interpretation and identification.

Science.gov (United States)

Schmidt, Patrick; Spinelli Sanchez, Océane; Kind, Claus-Joachim

2017-01-01

The Early Mesolithic of southwestern Germany, the so-called Beuronian (9600-7100 BC), is a period of important transformations in the way people lived, in their subsistence and in the stone tools they produced. One of the perhaps most spectacular re-inventions of that time is heat treatment of stones prior to their manufacture into tools. Although heat treatment has been understood as one of the defining characteristics of the Beuronian of southwestern Germany, and although its existence has been known for almost 30 years now, relatively few systematic studies on it are available. In this paper, we present such a study, aiming to shed light on two questions: (1) what technique and heating parameters were used in the Beuronian and (2) how reliable are the macroscopic proxies traditionally used to identify heat treatment in this context? We investigate these questions using a non-destructive archaeometric technique for measuring past heating temperatures of heat-treated stones and a quantitative surface roughness analysis aiming to understand the relations between surface aspect and heat treatment. These methods are applied to 46 Jurassic chert artefacts from the site Helga-Abri located in the Swabian Alb region of southwestern Germany. Our results document that an opportunistic low-investment procedure was used to heat stone, probably relying on the use of the above-ground part of regular camp-fires. We also found that the traditionally used macroscopic criteria, such as colour and surface gloss, cannot be unambiguously used to identify heat treatment in assemblages made from Jurassic chert. These findings have important implications for our understanding of the Beuronian lithic chaîne opératoire in terms of the investment in time and resources necessary, and for the refinement of archaeological techniques used to identify heat treatment in the Mesolithic of the Swabian Alb.

Evaluation of conjugate, radial heat transfer in an internally insulated composite pipe

NARCIS (Netherlands)

Reurings, C.; Koussios, S.; Bergsma, O.K.; Vergote, K.

2015-01-01

In order to compete with steel, a fibre-reinforced composite exhaust wall with a general-purpose resin system requires an effective but lightweight insulation layer. However a lack of experimental methods for heat transfer from turbulent gas flow to pipe walls lined with a porous insulation layer

Computer modelling system of the chemical composition and treatment parameters influence on mechanical properties of structural steels

OpenAIRE

L.A. Dobrzański; R. Honysz

2009-01-01

Purpose: This paper presents Neuro-Lab. It is an authorship programme, which use algorithms of artificial intelligence for structural steels mechanical properties estimation.Design/methodology/approach: On the basis of chemical composition, parameters of heat and mechanical treatment and elements of geometrical shape and size this programme has the ability to calculate the mechanical properties of examined steel and introduce them as raw numeric data or in graphic as influence charts. Possibl...

Heat treatment effect on structure and long-term rupture strength of γ/γ'-MeC nickel eutectic. Length memory effect

International Nuclear Information System (INIS)

Kishkin, S.T.; Svetlov, I.L.; Sorokina, L.P.; Morozova, S.G.; Golubovskij, E.R.; Yushakova, F.V.

1983-01-01

Heat treatment effect on structure, phase composition and long-term rupture strength of the directional eutectics on the nickel base with γ/γ'-MeC structure is studied at 900-1100 deg C. It is shown that quenching from the temperature of complete dissolving of γ'-phase and ageing (900 deg - 30 hr) provide an optimum size and morphology of the γ-phase and an increase of the long-term rupture strength at 900 and 1000 deg C. Repeated thermal treatment of cimens tested during definite time restores their structure, mechanical properties and dimensions

Neutron scattering investigation of carbon/carbon composites

International Nuclear Information System (INIS)

Prem, M.; Krexner, G.; Peterlik, H.

2005-01-01

Full text: Carbon/Carbon (C/C) composites, built up from bi-directionally woven fabrics from PAN based carbon fibers, pre-impregnated with phenolic resin followed by pressure curing and carbonization at 1000 o C and a final heat treatment at either 1800 o C or 2400 o C, were investigated by means of small-angle as well as wideangle elastic neutron scattering. Sample orientations arranging the carbon fibers parallel and perpendicular to the incoming beam were examined. Structural features of the composites, i.e. of the fibers as well as the inherently existing pores, are presented and the influence of the heat treatment on the structural properties is discussed. (author)

Effects of vacuum heat treatment on the photoelectric work function and surface morphology of multilayered silver–metal electrical contacts

International Nuclear Information System (INIS)

Akbi, Mohamed; Bouchou, Aïssa; Zouache, Noureddine

2014-01-01

Contact materials used for electrical breakers are often made with silver alloys. Mechanical and thermodynamical properties as well as electron emission of such complicated alloys present a lack of reliable and accurate experimental data. This paper deals mainly with electron work function (EWF) measurements about silver–metal (Ag–Me) electrical contacts (Ag–Ni (60/40) and Ag–W (50/50)), before and after surface heat treatments at 513 K–873 K, under UHV conditions (residual gas pressure of 1.4 × 10 −7 mbar). The electron work function (EWF) of silver alloyed contacts was measured photoelectrically, using both Fowler's method of isothermal curves and linearized Fowler plots. An interesting fact brought to light by this investigation is that after vacuum heat treatments, the diffusion and/or evaporation phenomena, affecting the atomic composition of the alloy surface, somehow confine the EWF of the silver–nickel alloy, Φ(Ag–Ni), determined at room temperature in interval]Φ(Ag), Φ(Ni) [=] 4.26 eV, 4.51 eV[. Surface analysis of two specimens before and after heating showed a significant increase of tungsten atomic proportion on the contact surface for Ag–W contacts after VH treatments. A multilayer model, taking into account the strong intergranular and volume segregation gives a good interpretation of the obtained results.

Preparation and Heat-Treatment of DWPF Simulants With and Without Co-Precipitated Noble Metals

International Nuclear Information System (INIS)

Koopman, David C.:Eibling, Russel E

2005-01-01

simulants were visually very viscous compared to the traditional SB3 simulant. (4) Heat-treatment reduced the viscosity of the two new simulants with and without coprecipitated noble metals, though they were still more viscous than the traditional SB3. (5) The approach of using a 97 C heat-treatment step to qualitatively simulate tank farm aging may not be optimal. A significant change in the base equivalent molarities of both simulants was observed during heat-treatment. (6) Heat-treatment appeared to make phosphates insoluble in water. The following recommendations came out of the work: (1) Washed slurry should be checked for TIC and base equivalents before calculating the final trim chemical additions of sodium carbonate and sodium hydroxide. (2) Final insoluble trim chemicals should be added to the slurry in the cross-flow filtration unit mixing tank, since significant slurry is lost in the CUF equipment. Adding the chemicals here would keep them in the correct proportion relative to the precipitated insoluble solids. (3) A composite wash and decant sample should be prepared containing proportionally weighted masses of each aqueous stream removed during preparation of a co-precipitated noble metal simulant. This sample should then be checked for noble metal losses. This would reduce the sample load, while still confirming that there was no significant noble metal loss. (4) A study of the impact of heat-treatment on existing simulants should be undertaken. If there is a shift in base equivalents, then SRNL acid stoichiometries may be biased relative to real waste. The study should be extended to several real wastes as well

In vitro solubility and bioactivity of Sr and Mg co-doped calcium phosphate glass-ceramics derived from different heat-treatment temperatures

International Nuclear Information System (INIS)

Cai Shu; Li Jianxin; Xu Guohua; Li, Xudong; Ye Xiaojian; Jiang Wei

2011-01-01

Highlights: ► Porous glass ceramics were prepared by controlled heat treatment process. ► A fast release of Mg ions has a great influence on the Ca/P ratio of the deposits. ► The chemical stability of the deposited apatite directly affects cell behavior. ► The glass ceramics heat-treated at 760 °C and 780 °C show less glass. ► The degradation rates are both compatible with cell growth and differentiation. - Abstract: CaO–P 2 O 5 –Na 2 O–SrO–MgO glass–ceramic system was prepared by controlled heat treatment process. Solubility and bioactivity of glass-ceramics were measured and evaluated in simulated body fluid (SBF) and cell culture medium respectively. The dissolution behavior of these glass-ceramics strongly depends on the amount and microstructure of the crystals precipitated by sintering treatment. Concerning the bioactivity, the onset of the apatite formation on the glass–ceramic system was directly dependent on the amount of bioactive glass amount which can be controlled using different temperatures of heat treatment. After immersing glass–ceramic in SBF, Mg ion as one of system composition can be released from residual glass and provides a high impact on the Ca/P ratio and chemical stability of the deposited apatite layer that directly affects cell attachment and proliferation in in vitro cell culture system. The glass ceramics heat-treated at 760 °C and 780 °C show less glass amount, and their degradation rates are both compatible with cell growth and differentiation.

Wear Behavior of Plasma Spray Deposited and Post Heat-Treated Hydroxyapatite (HA)-Based Composite Coating on Titanium Alloy (Ti-6Al-4V) Substrate

Science.gov (United States)

Kumari, Renu; Majumdar, Jyotsna Dutta

2018-04-01

The present study concerns a detailed evaluation of wear resistance property of plasma spray deposited composite hydroxyapatite (HA)-based (HA-50 wt pct TiO2 and HA-10 wt pct ZrO2) bioactive coatings developed on Ti-6Al-4V substrate and studying the effect of heat treatment on it. Heat treatment of plasma spray deposited samples has been carried out at 650 °C for 2 hours (for HA-50 wt pct TiO2 coating) and at 750 °C for 2 hours (for HA-10 wt pct ZrO2 coating). There is significant deterioration in wear resistance for HA-50 wt pctTiO2 coating and a marginal deterioration in wear resistance for HA-10 wt pct ZrO2 coating in as-sprayed state (as compared to as-received Ti-6Al-4V) which is, however, improved after heat treatment. The coefficient of friction is marginally increased for both HA-50 wt pct TiO2 and HA-10 wt pct ZrO2 coatings in as-sprayed condition as compared to Ti-6Al-4V substrate. However, coefficient of friction is decreased for both HA-50 wt pct TiO2 and HA-10 wt pct ZrO2 coatings after heat-treated condition as compared to Ti-6Al-4V substrate. The maximum improvement in wear resistance property is, however, observed for HA-10 wt pct ZrO2 sample after heat treatment. The mechanism of wear has been investigated.

Oxidation protection of austenite steels by heat-resisting glass-and-enamel coatings

International Nuclear Information System (INIS)

Lobzhanidze, V.N.; Korchagin, V.S.

1977-01-01

The use of glass-enamel coatings for corrosion protection of austenitic steels during heat treatment has been investigated. When working out the composition of the protective coating, the method of mathematical planning of experiments has been used. It is shown that the coating under investigation can best be used in heat treatment of items with a prolonged time of heating to 1050 deg C (18-20 hr). The savings resulting from the introduction of the heat-resistant glass-enamel coating exceed 30000 roubles

Improvement of corrosion resistance of Ni−Mo alloy coatings: Effect of heat treatment

Energy Technology Data Exchange (ETDEWEB)

Mousavi, R., E-mail: mousavi@scu.ac.ir [Department of Materials Science and Engineering, Shiraz University, Shiraz (Iran, Islamic Republic of); Bahrololoom, M.E. [Department of Materials Science and Engineering, Shiraz University, Shiraz (Iran, Islamic Republic of); Deflorian, F.; Ecco, L. [Department of Industrial Engineering, University of Trento, via Sommarive 9, Trento (Italy)

2016-02-28

Graphical abstract: - Highlights: • Conjunction between SEM, EIS, and Tafel measurements to obtain a coat with dense morphology and without crack. • An inverse Hall-Petch effect is observed after annealing the coatings, i.e. the coatings get harder as the grain size is increased by increasing annealing temperature up to 600 {sup o}C. • Heat treatment can improve the mechanical and corrosion properties of coatings. - Abstract: In this paper, Ni−Mo alloy coatings were deposited from bath containing sodium citrate, nickel sulphate, and sodium molybdate. Essentially, this work is divided into two mains parts: (i) the optimization on the coatings deposition parameters and (ii) the effect of the heat treatment. Polarization curves and electrochemical impedance spectroscopy were acquired using potentiostat/galvanostat and a frequency response analyzer, respectively. Morphology and chemical composition of the coatings were investigated by scanning electron microscopy and energy dispersive spectroscopy, respectively. Polarization curves at different condition revealed that electroplating at temperature 40 {sup o}C, pH 9 provides a dense coating with high efficiency. Following the optimization of the deposition parameters, the coatings were annealed at 200, 400, and 600 {sup o}C for 25 min. The results showed that the coatings obtained at temperature 40 {sup o}C, pH 9, and annealing at 600 {sup o}C has the highest corrosion resistance and microhardness.

STATIN CONTAINING COMPOSITIONS FOR TREATMENT OF CANCER

NARCIS (Netherlands)

Schiffelers, Raymond M.; Metselaar, J.M.; Storm, Gerrit

2008-01-01

The present invention relates to compositions comprising statin, and especially to the use of such compositions in the treatment of cancer or in the inhibition of cancer growth. More specifically, the invention relates to a method for targeting a statin to tumor tissue.

Influence of Heat Treatments on Carotenoid Content of Cherry Tomatoes

OpenAIRE

D'Evoli, Laura; Lombardi-Boccia, Ginevra; Lucarini, Massimo

2013-01-01

Tomatoes and tomato products are rich sources of carotenoids—principally lycopene, followed by β-carotene and lutein. The aim of this work was to study the effect of heat treatment on carotenoid content in cherry tomatoes. Raw and canned products were sampled and analysed; furthermore whole, skin and pulp fractions of cherry tomatoes were analysed when raw and home-processed, in order to better understand heat treatment effects. Lycopene content in canned tomatoes was two-fold higher than in ...

Optimisation of the T6 heat treatment of rheocast alloy A356

CSIR Research Space (South Africa)

Moller, H

2007-11-01

Full Text Available popular solution heat treatment employed for SSM processed A356 is 6 hours at 540oC (i.e. similar to that used for permanent mould cast A356)6,7,9. Only limited work has been performed on the optimisation of the solution heat treatment of SSM processed... was not adequately studied by either Dewhirst8 or Rosso and Actis Grande5. The optimum artificial aging heat treatment proposed in both papers5,8 is 180oC for 4 hours. This was also confirmed in this work, but importantly, this applies only when natural aging...

Assembly for melting and heat treatment

International Nuclear Information System (INIS)

Blumenfeld, M.

1976-11-01

Laboratory scale production of alloys having a precise alloying materials content and the exact heat treatment of metallurgical specimens are discussed. The design and assembly of two relevant instruments are described. These instruments include a laboratory vacuum induction furnace and a specially designed glass lathe, that enables even an unskilled operator to encapsulate and seal metallurgical specimens in glass capsules. (author)

Simple and Rapid Synthesis of Magnetite/Hydroxyapatite Composites for Hyperthermia Treatments via a Mechanochemical Route

Science.gov (United States)

Iwasaki, Tomohiro; Nakatsuka, Ryo; Murase, Kenya; Takata, Hiroshige; Nakamura, Hideya; Watano, Satoru

2013-01-01

This paper presents a simple method for the rapid synthesis of magnetite/hydroxyapatite composite particles. In this method, superparamagnetic magnetite nanoparticles are first synthesized by coprecipitation using ferrous chloride and ferric chloride. Immediately following the synthesis, carbonate-substituted (B-type) hydroxyapatite particles are mechanochemically synthesized by wet milling dicalcium phosphate dihydrate and calcium carbonate in a dispersed suspension of magnetite nanoparticles, during which the magnetite nanoparticles are incorporated into the hydroxyapatite matrix. We observed that the resultant magnetite/hydroxyapatite composites possessed a homogeneous dispersion of magnetite nanoparticles, characterized by an absence of large aggregates. When this material was subjected to an alternating magnetic field, the heat generated increased with increasing magnetite concentration. For a magnetite concentration of 30 mass%, a temperature increase greater than 20 K was achieved in less than 50 s. These results suggest that our composites exhibit good hyperthermia properties and are promising candidates for hyperthermia treatments. PMID:23629669

Simple and Rapid Synthesis of Magnetite/Hydroxyapatite Composites for Hyperthermia Treatments via a Mechanochemical Route

Directory of Open Access Journals (Sweden)

Tomohiro Iwasaki

2013-04-01

Full Text Available This paper presents a simple method for the rapid synthesis of magnetite/hydroxyapatite composite particles. In this method, superparamagnetic magnetite nanoparticles are first synthesized by coprecipitation using ferrous chloride and ferric chloride. Immediately following the synthesis, carbonate-substituted (B-type hydroxyapatite particles are mechanochemically synthesized by wet milling dicalcium phosphate dihydrate and calcium carbonate in a dispersed suspension of magnetite nanoparticles, during which the magnetite nanoparticles are incorporated into the hydroxyapatite matrix. We observed that the resultant magnetite/hydroxyapatite composites possessed a homogeneous dispersion of magnetite nanoparticles, characterized by an absence of large aggregates. When this material was subjected to an alternating magnetic field, the heat generated increased with increasing magnetite concentration. For a magnetite concentration of 30 mass%, a temperature increase greater than 20 K was achieved in less than 50 s. These results suggest that our composites exhibit good hyperthermia properties and are promising candidates for hyperthermia treatments.

Experimental heat treatment of silcrete implies analogical reasoning in the Middle Stone Age.

Science.gov (United States)

Wadley, Lyn; Prinsloo, Linda C

2014-05-01

Siliceous rocks that were not heated to high temperatures during their geological formation display improved knapping qualities when they are subjected to controlled heating. Experimental heat treatment of South African silcrete, using open fires of the kind used during the Middle Stone Age, shows that the process needed careful management, notwithstanding recent arguments to the contrary. Silcrete blocks fractured when heated on the surface of open fires or on coal beds, but were heated without mishap when buried in sand below a fire. Three silcrete samples, a control, a block heated underground with maximum temperature between 400 and 500 °C and a block heated in an open fire with maximum temperature between 700 and 800 °C, were analysed with X-ray powder diffraction (XRD), X-ray fluorescence (XRF), optical microscopy, and both Fourier transform infrared (FTIR) and Raman spectroscopy. The results show that the volume expansion during the thermally induced α- to β-quartz phase transformation and the volume contraction during cooling play a major role in the heat treatment of silcrete. Rapid heating or cooling through the phase transformation at 573 °C will cause fracture of the silcrete. Successful heat treatment requires controlling surface fire temperatures in order to obtain the appropriate underground temperatures to stay below the quartz inversion temperature. Heat treatment of rocks is a transformative technology that requires skilled use of fire. This process involves analogical reasoning, which is an attribute of complex cognition. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of heat treatment on the microstructure and properties of Ni based soft magnetic alloy.

Science.gov (United States)

Li, Chunhong; Ruan, Hui; Chen, Dengming; Li, Kejian; Guo, Donglin; Shao, Bin

2018-04-20

A Ni-based alloy was heat treated by changing the temperature and ambient atmosphere of the heat treatment. Morphology, crystal structure, and physical performance of the Ni-based alloy were characterized via SEM, XRD, TEM, and PPMS. Results show that due to the heat treatment process, the grain growth of the Ni-based alloy and the removal of impurities and defects are promoted. Both the orientation and stress caused by rolling are reduced. The permeability and saturation magnetization of the alloy are improved. The hysteresis loss and coercivity are decreased. Higher heat treatment temperature leads to increased improvement of permeability and saturation magnetization. Heat treatment in hydrogen is more conducive to the removal of impurities. At the same temperature, the magnetic performance of the heat-treated alloy in hydrogen is better than that of an alloy with heat treatment in vacuum. The Ni-based alloy shows an excellent magnetic performance on 1,373 K heat treatment in hydrogen atmosphere. In this process, the µ m , B s , P u , and H c of the obtained alloy are 427 mHm -1 , 509 mT, 0.866 Jm -3 , and 0.514 Am -1 , respectively. At the same time, the resistivity of alloy decreases and its thermal conductivity increases in response to heat treatment. © 2018 Wiley Periodicals, Inc.

Preparation of Gd2O3 Ultrafine Nanoparticles by Pulse Electrodeposition Followed by Heat-treatment Method

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Mustafa Aghazadeh

2016-12-01

Full Text Available Gd2O3 nanoparticles were prepared by a two–step process; cathodic electrodeposition followed by heat-treatment method. First, Gd(OH3 nanoparticles was galvanostatically deposited from nitrate bath on the steel substrate by pulse current (PC mode. The deposition experiments was conducted at a typical on-time and off-time (ton=1ms and toff=1ms for 60 min. The electrodeposited precursor was then heat-treated at 600 oC for 3h to obtain oxide product (i.e. Gd2O3. The morphological and structural analyses confirmed that the gadolinium hydroxynitrate nanoparticles with composition of [Gd(OH2.5(NO30.5 yH2O] and uniform size about 10 nm have been prepared during pulse cathodic electrodeposition process. Furthermore, mechanism of the gadolinium hydroxynitrate nanoparticles was explained based on the base (OH– electrogeneration process on the cathode surface. The morphological observations by SEM and TEM, and structural analyses via XRD and FT-IR revealed that the oxide product is composed of well-dispersed Gd2O3 nanoparticles with pure cubic crystalline structure. It was observed that the calcination process has no effect on the morphology of the Gd2O3 nanoparticles. Mechanism of oxide formation during heat-treatment step was investigated by DSC-TG analysis and discussed in detail. The results of this work showed that pulse current deposition followed by heat–treatment can be recognized as an easy and facile method for preparation of the Gd2O3 fine nanoparticles.

Effects of heat treatment on some physical properties of Douglas fir (Pseudotsuga menziesii) wood

Science.gov (United States)

Xianjun Li; Zhiyong Cai; Qunying Mou; Yiqiang Wu; Yuan Liu

2011-01-01

In this study the effect of heat treatment on some physical properties of Douglas fir (Pseudotsuga menziesii) was investigated. Wood specimens were subjected to heat treatment at 160, 180, 200 and 220°C for 1, 2, 3 and 4h. The results show that heat treatment resulted in a darkened color, decreased moisture performance and increased dimensional stability of...

Effect of heat treatment changes on swelling treatment of coal; Sekitan no bojun shori sayo ni oyobosu netsushori henka no eikyo

Energy Technology Data Exchange (ETDEWEB)

Satsuka, T.; Mashimo, K.; Wainai, T. [Nihon University, Tokyo (Japan). College of Science and Technology

1996-10-28

Discussions were given on effects of heat treatment at relatively low temperatures as a pretreatment for coal liquefaction on coal swelling and hydrogenolysis reaction. Taiheiyo coal was heated to 200{degree}C for one hour as a pretreatment. The attempted heating methods consisted of four steps of rapid heating (6.7{degree}C/min)quenching (20{degree}C/min), rapid heating/natural cooling (0.7{degree}C/min), heating (1.0{degree}C/min)/quenching, and heating/natural cooling. The swelling treatment was composed of adding methanol benzene into heat treated coal, and leaving it at room temperature for 24 hours. The hydrogenolysis was carried out by using a tetralin solvent and at an initial hydrogen pressure of 20 kg/cm{sup 2} and a temperature of 350{degree}C and for a time of one hour. Hydrogenolysis conversion in the heat treated coal was found lower than that of the original coal because of generation of liquefaction inactive components due to thermal polymerization. When the heat treated coal is swollen by using the solvent, gas yield from the hydrogenolysis reaction decreased due to gas suppression effect, and the conversion was lower than that of the original coal. Heat treatment suggests densification of the coal structure. Swollen coal shows no conspicuous difference in the heat treatment methods against the hydrogenolysis due to the swelling effect. 3 refs., 5 figs., 1 tab.

ARBOLITCONCRETE ON SILICATESODIUM COMPOSITE BINDER AND SCRAPS OF VINE

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Z. A. Manturov

2016-01-01

Full Text Available Aim.The results of experimental studies produce siliсatеsodium composite binder of calcareous stone sawing waste, anhydrous sodium silicate, and based on them wood concrete using as an organic filler vine cuttings for the production of heat-insulating, heat-insulating, structural and structural wall material.Methods.The main technological operations of the developed arbalitconcrete are given : preparation of a composite binder; production of organic filler from the vine; preparation of arbolit concrete mass; formation of arbolit concrete mass; low-temperature treatment (drying.Results. It is found that the composite binder derived from waste stone sawing and anhydrous sodium silicate at their joint fine grinding (Ssp = 3000 cm2 / g, acquires binding properties and with the appropriate seal and heat treatment hardens and gains strength characteristics sufficient for making arbolitconcrete using crushed vine.Conclusion. It was determined that arbolitobeton obtained on the basis of the crushed vine and silikatnatrievogo composite binder strength exceeds arbolitobetona from other types of binders and organic fillers of vegetable origin.

A novel laboratory scale method for studying heat treatment of cake flour

OpenAIRE

Chesterton, AKS; Wilson, David Ian; Sadd, PI; Moggridge, Geoffrey Dillwyn

2014-01-01

A lab-scale method for replicating the time–temperature history experienced by cake flours undergoing heat treatment was developed based on a packed bed configuration. The performance of heat-treated flours was compared with untreated and commercially heat-treated flour by test baking a high ratio cake formulation. Both cake volume and AACC shape measures were optimal after 15 min treatment at 130 °C, though their values varied between harvests. Separate oscillatory rheometry tests of cake ba...

Mathematical Simulation of Temperature Profiles within Microwave Heated Wood Made for Wood-Based Nano composites

International Nuclear Information System (INIS)

Li, X.; He, X.; Lv, J.; Wu, Y.; Luo, Y.; Chen, H.

2013-01-01

High intensive microwave pretreatment is a new method to modify wood for the fabrication of wood-based nano composites. Based on the physical law on heat transfer, a mathematical model to describe the temperature profiles within wood heated by high intensive microwave was established and simulated in this research. The results showed that the temperature profiles within wood were related to microwave heating methods; The temperature inside wood firstly increased and then gradually decreased along the direction of microwave transmission when the unilateral microwave heating was applied, and the temperature difference along the thickness direction of wood was very significant; The temperature with wood firstly increased and then gradually decreased from the wood surface to interior when the bilateral microwave heating was applied. Compared with the unilateral microwave heating, bilateral microwave heating is a better microwave heating method for the more uniform wood microwave pretreatment.

Influence of heat treatment on the microstructure and mechanical properties of Alloy 718 base metal and weldments

International Nuclear Information System (INIS)

Mills, W.J.

1979-06-01

Effect of heat treatment on the metallurgical structure and tensile properties of three heats of Alloy 718 base metal and an Alloy 718 GTA weldment were characterized. Heat treatments employed were the conventional (ASTM A637) precipitation treatment and a modified precipitation treatment designed to improve the toughness of the weldments. The GTA weldments were characterized in the as-welded condition. Light microscopy, thin foil, and surface replica electron microscopy revealed that the microstructure of this superalloy was sensitive to heat treatment and heat-to-heat variations. The modified aging treatment resulted in a larger grain size and a more homogeneous microstructure than the conventional treatments. The morphology of the primary strengthening γ phase was found to be finer and more closely spaced in the conventionally treated condition. Room and elevated temperature tensile testing revealed that the strength of the conventionally treated alloy was generally superior to that of the modified material. The conventional aging treatment resulted in greater heat-to-heat variations in tensile properties. This behavior was correlated with variations in the microstructure resulting from the precipitation heat treatments. The precipitate morphology of the GTA weldments was sensitive to heat treatment. The Laves phase was present in the interdendritic regions of both heat-treated welds. The modified aging treatment reduced the amount of Laves phase present in the weld zone. Room and elevated temperature tensile properties of the precipitation hardened weldments were relatively insensitive to heat treatment, suggesting that reduction in Laves phase from the weld zone had essentially no effect on tensile properties. As-welded GTA weldments exhibited lower strength levels and higher ductility values than heat-treated welds

A Study on Infrared Local Heat Treatment for AA5083 to Improve Formability and Automotive Part Forming

Science.gov (United States)

Lee, Eun-Ho; Yang, Dong-Yol; Ko, SeJin

2017-10-01

Automotive industries are increasingly employing aluminum alloys for auto parts to reduce vehicle weight. However, the low formability of aluminum alloys has been an obstacle to their application. To resolve the formability problem, some studies involving heat treatments under laboratory conditions have been reported. However, for industrial applications, the heat treatment sequence, heating energy efficiency, and a commercial part test should be studied. This work shows an infrared (IR) local heat treatment, heating only small areas where the heat treatment is required, for an aluminum alloy to improve the formability with a reduction of heating energy. The experiment shows that the formability drastically increases when the aluminum alloy is heat treated between two forming stages, referred to as intermediate heat treatment. The microstructures of the test pieces are evaluated to identify the cause of the increase in the formability. For an industrial application, an aluminum tailgate, which cannot be manufactured without heat treatment, was successfully manufactured by the IR local heat treatment with a reduction of energy. A simulation was also conducted with a stress-based forming limit diagram, which is not affected by the strain path and heat treatment histories. The simulation gives a good prediction of the formability improvement.

Effect of heat moisture treatment and annealing on physicochemical ...

African Journals Online (AJOL)

Red sorghum starch was physically modified by annealing and heat moisture treatment. The swelling power and solubility increased with increasing temperature range (60-90°), while annealing and heatmoisture treatment decreased swelling power and solubility of starch. Solubility and swelling were pH dependent with ...

Heat treatments of TiAl-Cr-V casting alloy

International Nuclear Information System (INIS)

Pu, Z.J.; Ma, J.L.; Wu, K.H.

1995-01-01

The need to investigate various kinds of fine microstructure based on casting TiAl alloy led to development of a multiple-stage heat treatment procedure. The first stage required the transformation of as-cast lamellar structure into near-gamma structure, followed by required transformation of near-gamma structure into various kinds of fine microstructure. The as-cast lamellar structure can be changed into near-gamma structure by annealing the alloy at 1,200 C for at least 50 hours. During the annealing process, two mechanisms are involved in transforming the lamellar structure into a near-gamma structure. One is the discontinuous coarsening (DC) process, and the other is the continuous coarsening (CC) process. With the near-gamma structure as an initial structure, the alloy being heat-treated in the γ + α and in the α fields can produce various kinds of microstructure with fine grain size. These microstructure significantly differ from the microstructure produced by heat-treating the deformed lamellar structure. Results of the investigation show that careful control of the time of the heat-treatment process in the single a field can produce a fine fully lamellar structure

The Effect of Heat Treatments on Alloying of Pre-mixed Al + 4.5 wt. % Cu Powders

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Kübra KÖPRÜLÜ

2018-06-01

Full Text Available In this study, 4.5 wt. % Cu powder was added to Al powder and mixed for 45 minutes to produce premixed metal powders. Premixed powders were compacted by cold pressing at 20 MPa. After that these samples were pressed at 500℃ under 200 MPa for 30 minutes by hot pressed method. Hot pressed block samples were subjected to diffusion annealing at 540 ℃ for 2, 4, 8, 16, 32 hours. These samples, produced by powder metallurgy, are used at metallographic and microscopic researches to investigate the diffusion process. During the diffusion annealing, it was determined that significant amount of copper powder particles was dissolved in the Al matrix by diffusion. Diffusion annealing was followed by aging heat treatment, characterized by metallographic and mechanical tests. According to the increasing the annealing time, the homogeneity of the chemical composition is not provided, however the increasing of the heat treatment (T6 capability of the produced parts, and partial porosity which is believed to be due to atomic diffusion, have been observed. Moreover, in the XRD analyses, it was determined that the phases of -Al,  and  were formed in the microstructure.

Data on post irradiation experiments of heat resistant ceramic composite materials. PIE for 97M-13A

Energy Technology Data Exchange (ETDEWEB)

Baba, Shin-ichi; Ishihara, Masahiro; Souzawa, Shizuo [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Sekino, Hajime [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

2003-03-01

The research on the radiation damage mechanism of heat resistant ceramic composite materials is one of the research subjects of the innovative basic research in the field of high temperature engineering, using the High Temperature engineering Test Reactor (HTTR). Three series of irradiation tests on the heat resistant ceramic composite materials, first to third irradiation test program, were carried out using the Japan Material Testing Reactor (JMTR). This is a summary report on the first irradiation test program; irradiation induced dimensional change, thermal expansion coefficient, X-ray diffraction and {gamma}-ray spectrum are reported. (author)

Evaluation of heat treatment schedules for emerald ash borer (Coleoptera: Buprestidae).

Science.gov (United States)

Myers, Scott W; Fraser, Ivich; Mastro, Victor C

2009-12-01

The thermotolerance of the emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), was evaluated by subjecting larvae and prepupae to a number of time-temperature regimes. Three independent experiments were conducted during 2006 and 2007 by heating emerald ash borer infested firewood in laboratory ovens. Heat treatments were established based on the internal wood temperature. Treatments ranged from 45 to 65 degrees C for 30 and 60 min, and the ability of larvae to pupate and emerge as adults was used to evaluate the success of each treatment. A fourth experiment was conducted to examine heat treatments on exposed prepupae removed from logs and subjected to ambient temperatures of 50, 55, and 60 degrees C for 15, 30, 45, and 60 min. Results from the firewood experiments were consistent in the first experiment. Emergence data showed emerald ash borer larvae were capable of surviving a temperatures-time combination up to 60 degrees C for 30 min in wood. The 65 degrees C for 30 min treatment was, however, effective in preventing emerald ash borer emergence on both dates. Conversely, in the second experiment using saturated steam heat, complete mortality was achieved at 50 and 55 degrees C for both 30 and 60 min. Results from the prepupae experiment showed emerald ash borer survivorship in temperature-time combinations up to 55 degrees C for 30 min, and at 50 degrees C for 60 min; 60 degrees C for 15 min and longer was effective in preventing pupation in exposed prepupae. Overall results suggest that emerald ash borer survival is variable depending on heating conditions, and an internal wood temperature of 60 degrees C for 60 min should be considered the minimum for safe treatment for firewood.

Heat treatment evaluation of steel ASTM A-131 grade A by X-Ray diffraction

Energy Technology Data Exchange (ETDEWEB)

Ferreira Junior, Francisco; Feio, Luciana Gaspar; Costa, Ednelson Silva; Rodrigues, Lino Alberto Soares; Braga, Eduardo Magalhaes, E-mail: juniorferrer93@gmail.com [Universidade Federal do Pará (UFPA), Belém, PA (Brazil)

2016-07-01

Full text: This study evaluates the residual stress of naval steel ASTM A-131 grade A before and after heat treatment. Residual stresses were determined by the technique of X-ray diffraction (XRD). Before heat treatment the residual stress measurements were made at 36 (thirty six) points distributed in a specimen with dimensions of 400 mm long, 200 mm wide and 95 mm thick, then the plate under analysis was brought to the oven for the implementation of heat treatment. To check the performance of the heat treatment, the plate was again subjected to XRD measurements of the same points previously measured in order to compare the residual stresses. As result, there was a reduction of residual stresses with the application of heat treatment. References: [1] COLPAERT, H. Metalografia dos Produtos Siderurgicos Comuns. 4 Edição. Editora Blucher. Saõ Paulo, SP, 2008. [2] HILL, R. Princípios de Metalurgia Física, 1992. (author)

Evaluation of the Characteristics of the Aluminum Alloy Casting Material by Heat Treatment

International Nuclear Information System (INIS)

Lee, Syung Yul; Park, Dong Hyun; Won, Jong Pil; Kim, Yun Hae; Lee, Myung Hoon; Moon, Kyung Man; Jeong, Jae Hyun

2012-01-01

Aluminum is on active metal, but it is well known that its oxide film plays a role as protective barrier which is comparatively stable in air and neutral aqueous solution. Thus, aluminum alloys have been widely applied in architectural trim, cold and hot-water storage vessels and piping etc., furthermore, the aluminum alloy of AC8A have been widely used in mold casting material of engine piston because of its properties of temperature and wear resistance. In recent years, the oil price is getting higher and higher, thus the using of low quality oil has been significantly increased in engines of ship and vehicle. Therefore it is considered that evaluation of corrosion resistance as well as wear resistance of AC8A material is also important to improve its property and prolong its lifetime. In this study, the effect of solution and tempering heat treatment to corrosion and wear resistance is investigated with electrochemical method and measurement of hardness. The hardness decreased with solution heat treatment compared to mold casting condition, but its value increased with tempering heat treatment and exhibited the highest value of hardness with tempering heat treatment temperature at 190 .deg. C for 24hrs. Furthermore, corrosion resistance increased with decreasing of the hardness, and decreased with increasing of the hardness reversely. As a result, it is suggested that the optimum heat treatment to improve both corrosion and wear resistance is tempering heat treatment temperature at 190 .deg. C for 16hrs

Improvement of stress-rupture life of GTD-111 by second solution heat treatment

International Nuclear Information System (INIS)

Yang, Caixiong; Xu, Yulai; Zhang, Zixing; Nie, Heng; Xiao, Xueshan; Jia, Guoqing; Shen, Zhi

2013-01-01

Highlights: ► The second solution heat treatment promoted the solution of γ–γ′ eutectic into γ matrix. ► The volume fraction of γ′ increases significantly after adding the second solution heat treatment. ► The improved stress-rupture life is primarily due to the increased volume fraction of γ′ phase. -- Abstract: An added second solution heat treatment was conducted to investigate its effects on the microstructures and stress-rupture properties of GTD-111. The microstructures were analyzed by scanning electron microscope after each step of heat treatments. The stress-rupture life of GTD-111 dramatically increases from about 180 to 288 h at 871 °C/310 MPa after adding a second solution heat treatment. The added second solution heat treatment promoted the solution of γ–γ′ eutectic into γ matrix, and facilitated the nucleation and precipitate of the secondary γ′ particles. The distribution of γ′ phase becomes much denser, the width of γ matrix channel is also reduced, and the volume fraction of γ′ phase significantly increases from about 29.3% to 44.2%. The improved stress-rupture life is primarily due to the increased volume fraction of γ′ phase. The carbides mainly consist of MC and a small amount of M 23 C 6 , which may prevent the dislocation moving and/or grain boundary sliding, and further improve the stress-rupture properties of GTD-111.

In situ post-weld heat treatment on martensitic stainless steel turbine runners using a robotic induction heating process to control temperature distribution

Science.gov (United States)

Boudreault, E.; Hazel, B.; Côté, J.; Godin, S.

2014-03-01

A new robotic heat treatment process is developed. Using this solution it is now possible to perform local heat treatment on large steel components. Crack, cavitation and erosion repairs on turbine blades and Pelton buckets are among the applications of this technique. The proof of concept is made on a 13Cr-4Ni stainless steel designated "CA6NM". This alloy is widely used in the power industry for modern system components. Given the very tight temperature tolerance (600 to 630 °C) for post-weld heat treatment on this alloy, 13Cr-4Ni stainless steel is very well suited for demonstrating the possibilities of this process. To achieve heat treatment requirements, an induction heating system is mounted on a compact manipulator named "Scompi". This robot moves a pancake coil in order to control the temperature distribution. A simulator using thermal finite element analysis is first used for path planning. A feedback loop adjusts parameters in function of environmental conditions.

In situ post-weld heat treatment on martensitic stainless steel turbine runners using a robotic induction heating process to control temperature distribution

International Nuclear Information System (INIS)

Boudreault, E; Hazel, B; Côté, J; Godin, S

2014-01-01

A new robotic heat treatment process is developed. Using this solution it is now possible to perform local heat treatment on large steel components. Crack, cavitation and erosion repairs on turbine blades and Pelton buckets are among the applications of this technique. The proof of concept is made on a 13Cr-4Ni stainless steel designated C A6NM . This alloy is widely used in the power industry for modern system components. Given the very tight temperature tolerance (600 to 630 °C) for post-weld heat treatment on this alloy, 13Cr-4Ni stainless steel is very well suited for demonstrating the possibilities of this process. To achieve heat treatment requirements, an induction heating system is mounted on a compact manipulator named S compi . This robot moves a pancake coil in order to control the temperature distribution. A simulator using thermal finite element analysis is first used for path planning. A feedback loop adjusts parameters in function of environmental conditions

Assessment of radio frequency heating on composition, microstructure, flowability and rehydration characteristics of milk powder

Directory of Open Access Journals (Sweden)

Yu ZHONG

2017-10-01

Full Text Available Abstract Radio frequency heating (RFH provides higher efficiency and more uniform heating zone compared with conventional method. The aim of present work is to evaluate the effect of RFH (at 90 °C for 5 or 10 min on the changes in composition (protein oxidation and fat distribution, microstructure, flow characteristic and rehydration property of infant milk powder. The results indicate that the concentration of protein dityrosine was slightly enhanced, more free fat appeared on powder surfaces (> 50% increase, and porosity in powder matrix as tested by SEM was increased after RFH treatment. For powder flowability, raw sample had low cohesiveness (specific energy = 4.39 mJ/g, and RFH provided better flowability and decreased compressibility. Moreover, RFH had some negative impacts on wettability and solubility of powder particles with contact angle increase at least 5% and solubility decrease of 2%~4%, indicating worse rehydration abilities. Guggenheim-Anderson-de Boer (GAB model was applied to fit moisture vapor sorption isotherms, and longer RFH duration leading to higher c values (about 63% increase at 10 min. In addition, the RFH initiated browning reaction as CIE a* values increased from -1.8 to -1.3.

Heat treatment of the EN AC-AlSi9Cu3(Fe alloy

Directory of Open Access Journals (Sweden)

J. Pezda

2010-04-01

Full Text Available Silumins are widely used in automotive, aviation and shipbuilding industries; as having specific gravity nearly three times lower than specific gravity of cast iron the silumins can be characterized by high mechanical properties. Additionally, they feature good casting properties, good machinability and good thermal conductivity. i.e. properties as required for machinery components operating in high temperatures and at considerable loads. Mechanical properties of the silumins can be upgraded, implementing suitably selected heat treatment. In the paper is presented an effect of modification and heat treatment processes on mechanical properties of the EN AC-AlSi9Cu3(Fe alloy. Investigated alloy has undergone typical processes of modification and refining, and next heat treatment. Temperature range of the heat treatment operations was determined on base of curves from the ATD method. Obtained results concern registered melting and solidification curves from the ATD method and strength tests. On base of the performed tests one has determined range of the heat treatment parameters which would assure obtainment of the best possible mechanical properties of the EN AC-AlSi9Cu3(Fe alloy.

Effects of thermal and enzymatic treatments and harvesting time on the microbial quality and chemical composition of fibre hemp (Cannabis sativa L.)

Energy Technology Data Exchange (ETDEWEB)

Nykter, Minna; Kymaelaeinen, Hanna-Riitta; Sjoeberg, Anna-Maija [Department of Agrotechnology, University of Helsinki, P.O. Box 28, FI-00014 University of Helsinki (Finland); Thomsen, Anne Belinda; Thygesen, Anders [Biosystems Department, Risoe National Laboratory, P.O. Box 49, DK-4000 Roskilde (Denmark); Lilholt, Hans [Materials Research Department, Risoe National Laboratory, P.O. Box 49, DK-4000 Roskilde (Denmark); Koponen, Hilkka [Department of Applied Biology, Section of Plant Pathology, University of Helsinki, P.O. Box 27, FI-00014 University of Helsinki (Finland)

2008-05-15

The aim of the present study was to examine the effects of pectinase enzyme treatment followed by thermal treatments (steam explosion and dry heating) on the microbial quality and chemical composition of hemp fibres. Before these treatments, the fibres were separated manually from the stems harvested after stand retting in the field before frost, after early frost or in the following spring. The enzymatic treatment of hemp promoted growth of moulds on the fibres (500-fold increase in colony-forming units (cfu)), whereas steam explosion reduced the amount of moulds to a relatively constant level of 10{sup 2} cfu/g dw. The amount of bacteria was not markedly affected by enzymatic treatment but was reduced tenfold after steam explosion. Steam explosion is thereby a potentially good process for the production of hemp fibres with low fungal contamination, which can be of importance in insulation materials. Dry heating had no effect on mould and bacterial counts at temperatures below 120 C and durations less than 60 min. The chemical composition was affected by the enzymatic treatment due to extraction and degradation of water-soluble components, pectin and ash. Thus the cellulose content increased by 6% w/w to 67-70% w/w. Steam explosion of the untreated hemp fibres increased the cellulose content to 74% w/w, whereas steam explosion of enzymatically treated hemp increased the cellulose content to 78% w/w. (author)

Effect of alkali and heat treatments for bioactivity of TiO{sub 2} nanotubes

Energy Technology Data Exchange (ETDEWEB)

Kim, Seo young, E-mail: mast6269@nate.com [Dept. of Dental Biomaterials and Institute of Bio degradable material, Institute of Oral Bioscience and BK21 plus project, School of Dentistry, Chonbuk National University, Jeonju, 561-756 (Korea, Republic of); Kim, Yu kyoung, E-mail: yk0830@naver.com [Dept. of Dental Biomaterials and Institute of Bio degradable material, Institute of Oral Bioscience and BK21 plus project, School of Dentistry, Chonbuk National University, Jeonju, 561-756 (Korea, Republic of); Park, Il song, E-mail: ilsong@jbnu.ac.kr [Division of Advanced Materials Engineering, Research Center for Advanced Materials Development and Institute of Biodegradable Materials, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Jin, Guang chun, E-mail: jingc88@126.com [Oral Medical College, Beihua University, Jilin City 132013 (China); Bae, Tae sung, E-mail: bts@jbnu.ac.kr [Dept. of Dental Biomaterials and Institute of Bio degradable material, Institute of Oral Bioscience and BK21 plus project, School of Dentistry, Chonbuk National University, Jeonju, 561-756 (Korea, Republic of); Lee, Min ho, E-mail: mh@jbnu.ac.kr [Dept. of Dental Biomaterials and Institute of Bio degradable material, Institute of Oral Bioscience and BK21 plus project, School of Dentistry, Chonbuk National University, Jeonju, 561-756 (Korea, Republic of)

2014-12-01

Highlights: • TiO{sub 2} nanotubes formed via anodization were treated by alkali and heat. • The surface roughness was increased after alkali treatment (p < 0.05). • After alkali and heat treatment, the wettability was better than before treatment. • Alkali treated TiO{sub 2} nanotubes were shown higher HAp formation in SBF. • Heat treatment affected on the attachment of cells for alkali treated nanotubes. - Abstract: In this study, for improving the bioactivity of titanium used as an implant material, alkali and heat treatments were carried out after formation of the nanotubes via anodization. Nanotubes with uniform length, diameter, and thickness were formed by anodization. The alkali and heat-treated TiO{sub 2} nanotubes were covered with the complex network structure, and the Na compound was generated on the surface of the specimens. In addition, after 5 and 10 days of immersion in the SBF, the crystallized OCP and HAp phase was significantly increased on the surface of the alkali-treated TiO{sub 2} nanotubes (PNA) and alkali and heat-treated TiO{sub 2} nanotubes (PNAH) groups. Cell proliferation was decreased due to the formation of amorphous sodium titanate (Na{sub 2}TiO{sub 3}) layer on the surface of the PNA group. However, anatase and crystalline sodium titanate were formed on the surface of the PNAH group after heat treatment at 550 °C, and cell proliferation was improved. Thus, PNA group had higher HAp forming ability in the simulated body fluid. Additional heat treatment affected on enhancement of the bioactivity and the attachment of osteoblasts for PNA group.

EFFECT OF HEAT TREATMENT ON SOYBEAN PROTEIN SOLUBILITY

Directory of Open Access Journals (Sweden)

RODICA CĂPRIŢĂ

2007-05-01

Full Text Available The use of soybean products in animal feeds is limited due to the presence of antinutritional factors (ANF. Proper heat processing is required to destroy ANF naturally present in raw soybeans and to remove solvent remaining from the oil extraction process. Over and under toasting of soybean causes lower nutritional value. Excessive heat treatment causes Maillard reaction which affects the availability of lysine in particular and produces changes to the chemical structure of proteins resulting in a decrease of the nutritive value. The objective of this study was to evaluate the effect of heating time on the protein solubility. The investigation of the heating time on protein solubility in soybean meal (SBM revealed a negative correlation (r = -0.9596. Since the urease index is suitable only for detecting under processed SBM, the protein solubility is an important index for monitoring SBM quality.

Optimization of Composition and Heat Treating of Die Steels for Extended Lifetime; FINAL

International Nuclear Information System (INIS)

David Schwam; John F, Wallace; Quanyou Zhou

2002-01-01

An ''average'' die casting die costs fifty thousand dollars. A die used in making die cast aluminum engine blocks can cost well over one million dollars. These costs provide a strong incentive for extension of die life. While vacuum quenched Premium Grade H13 dies have become the most widely used in the United States, tool makers and die casters are constantly searching for new steels and heat treating procedures to extend die life. This project was undertaken to investigate the effects of composition and heat treating on die life and optimize these parameters

Computerized property prediction and process planning in heat treatment of steels

Energy Technology Data Exchange (ETDEWEB)

Gergely, M. (Steel Advisory Centre for Industrial Technologies (SACIT), Budapest (Hungary)); Somogyi, S. (Steel Advisory Centre for Industrial Technologies (SACIT), Budapest (Hungary)); Kohlheb, R. (Steel Advisory Centre for Industrial Technologies (SACIT), Budapest (Hungary))

1994-01-01

Recent years have seen widespread interest in the establishment of prediction methods, based on phenomenological description and computer simulation of transformation processes during heat treatment, and in the introduction of software for technological planning. The steady development of this approach is aimed at meeting the requirement of metallurgists, design engineers dealing with material selection and dimensioning, and technologists planning heat treatment processes. Research in this field of computer simulation has been concentrated so far on two main areas of interest: . Modelling of transformation processes and the prediction of microstructures and/or properties, . Developing program packages to help solve concrete tasks such as material selection, on-line process control and monitoring, and the design of heat-treating operations. During the last two decades in the field of heat treatment, various mathematical models with different accuracy and complexity have been developed. In this paper, an attempt is made to outline some important results in computer simulation and computerized property prediction without aiming at completeness. The topic is restricted to quenched and tempered, and case-hardened steels. (orig.)

Production of Cu/diamond composites for first-wall heat sinks

International Nuclear Information System (INIS)

Nunes, D.; Correia, J.B.; Carvalho, P.A.; Shohoji, N.; Fernandes, H.; Silva, C.; Alves, L.C.; Hanada, K.; Osawa, E.

2011-01-01

Due to their suitable thermal conductivity and strength, copper-based materials have been considered appropriate heat sinks for first wall panels in nuclear fusion devices. However, increased thermal conductivity and mechanical strength are demanded and the concept of property tailoring involved in the design of metal matrix composites advocates for the potential of nanodiamond dispersions in copper. Copper-nanodiamond composite materials can be produced by mechanical alloying followed by a consolidation operation. Yet, this powder metallurgy route poses several challenges: nanodiamond presents intrinsically difficult bonding with copper; contamination by milling media must be closely monitored; and full densification and microstructural homogeneity should be obtained with consolidation. The present line of work is aimed at an optimization of the processing conditions of Cu-nanodiamond composites. The challenges mentioned above have been addressed, respectively, by incorporating chromium in the matrix to form a stable carbide interlayer binding the two components; by assessing the contamination originating from the milling operation through particle-induced X-ray emission spectroscopy; and by comparing the densification obtained by spark plasma sintering with hot-extrusion data from previous studies.

In vitro and in vivo evaluation of SLA titanium surfaces with further alkali or hydrogen peroxide and heat treatment

International Nuclear Information System (INIS)

Zhang, E W; Wang, Y B; Zheng, Y F; Shuai, K G; Gao, F; Bai, Y J; Cheng, Y; Xiong, X L; Wei, S C

2011-01-01

The present study aimed to evaluate the bioactivity of titanium surfaces sandblasted with large-grit corundum and acid etched (SLA) plus further alkali or hydrogen peroxide and heat treatment for dental implant application. Pure titanium disks were mechanically polished as control surface (Ti-control) and then sandblasted with large-grit corundum and acid etched (SLA). Further chemical modifications were conducted using alkali and heat treatment (ASLA) and hydrogen peroxide and heat treatment (HSLA) alternatively. The surface properties were characterized by scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), and contact angle and roughness measurements. Further evaluation of surface bioactivity was conducted by MC3T3-E1 cell attachment, proliferation, morphology, alkaline phosphatase (ALP) activity and calcium deposition on the sample surfaces. After insertion in the beagle's mandibula for a specific period, cylindrical implant samples underwent micro-CT examination and then histological examination. It was found that ASLA and HSLA surfaces significantly increased the surface wettability and MC3T3-E1 cell attachment percentage, ALP activity and the quality of calcium deposition in comparison with simple SLA and Ti-control surfaces. Animal studies showed good osseointegration of ASLA and HSLA surfaces with host bone. In conclusion, ASLA and HSLA surfaces enhanced the bioactivity of the traditional SLA surface by integrating the advantages of surface topography, composition and wettability.

In vitro and in vivo evaluation of SLA titanium surfaces with further alkali or hydrogen peroxide and heat treatment

Energy Technology Data Exchange (ETDEWEB)

Zhang, E W; Wang, Y B; Zheng, Y F [State Key Laboratory for Turbulence and Complex System, Department of Advanced Materials and Nanotechnology, College of Engineering, Peking University, Beijing 100871 (China); Shuai, K G; Gao, F; Bai, Y J; Cheng, Y; Xiong, X L [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Wei, S C, E-mail: enwei@pku.edu.cn, E-mail: yanbo.pku@pku.edu.cn, E-mail: shuaikegang@gmail.com, E-mail: soarfgoal@gmail.com, E-mail: norice86@163.com, E-mail: chengyan@pku.edu.cn, E-mail: xxiaoling11@hotmail.com, E-mail: yfzheng@pku.edu.cn, E-mail: weishicheng99@163.com [Department of Oral and Maxillofacial Surgery, School of Stomatology, Peking University, Beijing 100081 (China)

2011-04-15

The present study aimed to evaluate the bioactivity of titanium surfaces sandblasted with large-grit corundum and acid etched (SLA) plus further alkali or hydrogen peroxide and heat treatment for dental implant application. Pure titanium disks were mechanically polished as control surface (Ti-control) and then sandblasted with large-grit corundum and acid etched (SLA). Further chemical modifications were conducted using alkali and heat treatment (ASLA) and hydrogen peroxide and heat treatment (HSLA) alternatively. The surface properties were characterized by scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), and contact angle and roughness measurements. Further evaluation of surface bioactivity was conducted by MC3T3-E1 cell attachment, proliferation, morphology, alkaline phosphatase (ALP) activity and calcium deposition on the sample surfaces. After insertion in the beagle's mandibula for a specific period, cylindrical implant samples underwent micro-CT examination and then histological examination. It was found that ASLA and HSLA surfaces significantly increased the surface wettability and MC3T3-E1 cell attachment percentage, ALP activity and the quality of calcium deposition in comparison with simple SLA and Ti-control surfaces. Animal studies showed good osseointegration of ASLA and HSLA surfaces with host bone. In conclusion, ASLA and HSLA surfaces enhanced the bioactivity of the traditional SLA surface by integrating the advantages of surface topography, composition and wettability.

Maleimido substituted cyclotriphosphazene resins for fire and heat resistant composites

Science.gov (United States)

Kumar, D.; Fohlen, G. M.; Parker, J. A.

1983-01-01

A new class of fire- and heat-resistant matrix resins have been synthesized by the thermal polymerization of maleimido substituted phenoxycyclotriphosphazenes. The resins have exhibited a char yield of 82 percent at 800 C in nitrogen and 81 percent at 700 C in air. Graphite-fabric laminates based on a resin of this class have shown a limiting oxygen index of 100 percent even at 300 C. Details of the fabrication of the resins and the composites and testing procedures are discussed.

Effect of heat input on dissimilar welds of ultra high strength steel and duplex stainless steel: Microstructural and compositional analysis

Energy Technology Data Exchange (ETDEWEB)

Tasalloti, H., E-mail: hamed.tasalloti.kashani@student.lut.fi; Kah, P., E-mail: paul.kah@lut.fi; Martikainen, J., E-mail: jukka.martikainen@lut.fi

2017-01-15

The effect of heat input on the microstructure and compositional heterogeneity of welds of direct-quenched ultra high strength steel (Optim 960 QC) and duplex stainless steel (UNS S32205) was studied. The dissimilar welds were made using GMAW with a fully austenitic filler wire. In addition to grain coarsening in the heat affected zone (HAZ) of the ferritic side, it was found that an increase in heat input correlatively increased the proportional volume of bainitic to martensitic phases. Coarse ferritic grains were observed in the duplex HAZ. Higher heat input, however, had a beneficial effect on the nucleation of austenite in the HAZ. Heat input had a regulatory effect on grain growth within the austenitic weld and more favorable equiaxed austenite was obtained with higher heat input. On the ferritic side of the welds, macrosegregation in the form of a martensitic intermediate zone was observed for all the cooling rates studied. However, on the duplex side, macrosegregation in the fusion boundary was only noticed with higher cooling rates. Microstructural observations and compositional analysis suggest that higher heat input could be beneficial for the structural integrity of the weld despite higher heat input increasing the extent of adverse coarse grains in the HAZ, especially on the ferritic side. - Highlights: •The effect of heat input on dissimilar welds of UHSS and DSS was studied. •Transmutation of the microstructure was discussed in detail. •The influence of heat input on compositional heterogeneity of welds was described. •Higher heat input enhanced bainitic transformation on the ferritic side. •Macrosegregation was affected by the amount of heat input on the DSS side.

Composites of Graphene Nanoribbon Stacks and Epoxy for Joule Heating and Deicing of Surfaces.

Science.gov (United States)

Raji, Abdul-Rahman O; Varadhachary, Tanvi; Nan, Kewang; Wang, Tuo; Lin, Jian; Ji, Yongsung; Genorio, Bostjan; Zhu, Yu; Kittrell, Carter; Tour, James M

2016-02-10

A conductive composite of graphene nanoribbon (GNR) stacks and epoxy is fabricated. The epoxy is filled with the GNR stacks, which serve as a conductive additive. The GNR stacks are on average 30 nm thick, 250 nm wide, and 30 μm long. The GNR-filled epoxy composite exhibits a conductivity >100 S/m at 5 wt % GNR content. This permits application of the GNR-epoxy composite for deicing of surfaces through Joule (voltage-induced) heating generated by the voltage across the composite. A power density of 0.5 W/cm(2) was delivered to remove ∼1 cm-thick (14 g) monolith of ice from a static helicopter rotor blade surface in a -20 °C environment.

Suppression of outgassing from spindt-type cold-cathode by heat treatment

International Nuclear Information System (INIS)

Miyo, Yasuhiko; Ogiwara, Norio; Saidoh, Masahiro; Hayashi, Naoki; Turuta, Kouichi.

1995-01-01

In Spindt type cold cathode electron source (hereafter, referred to as FEA), field emission is used for extracting electrons. It was made clear that the FEA is an excellent electron source that never causes gas release by heating peripheral parts. But the gas release form the FEA was confirmed though it was slight accompanying the extraction of current. This gas release becomes a problem when pressure measurement is carried out by using the FEA in ultrahigh or extremely high vacuum. If the gas release occurs by the effect of the heat generation at the tip of an emitter accompanying the extraction of electron current, it is possible to reduce the gas release by carrying out the heat treatment of the FEA was attempted, and as the result, it was elucidated that by the heat treatment at 400degC, the gas release form the FEA was able to be suppressed. However, a new problem that the insulation between gate and emitter deteriorated and broke during the extraction of current occurred. The experimental method and the results of the reduction of gas release by heat treatment and the observation of the broken FEA with a scanning electron microscope are reported. Also the problem that in the FEA which was heat-treated at 400degC, the current has decreased from 500 μA to 100 μA in about 100 hours occurred. As to these problems, it is necessary to continue the experiment further. (K.I.)

Heat treatment of large-sized welded rotors of steam turbines for atomic power stations

Energy Technology Data Exchange (ETDEWEB)

Kutasov, R F; Mukhina, M P; Tustanovskii, A S

1977-01-01

The heat treatment of a welded rotor of grade 25Kh2NMFA steel for steam turbines of nuclear power plants was considered. A following heat treatment schedule was suggested: charging the rotor in to a furnace at 100-150 deg C, heating to 200-250 deg C and holding for 12 hrs; slow heating (10 deg C/h) to 400-450 deg C and holding for 12 hrs; slow heating to 630-640 deg C and holding for 50 hrs, cooling at a rate of 5 deg C/h down to 100 deg C, holding for 20 hrs and cooling with the furnace open. The proposed heat treatment schedule of a duration of 356 hrs ensures a temperature gradient throughout the cross section and the length of the rotor of not more than +-5 deg C, least deviations of geometric dimensions and makes possible machining finish to within 0-0.02 mm. Described are the particularities of the design of a roll-out hearth electric chamber furnace, measuring 13000x5500x5000 mm and built for the purpose of carrying out said heat treatment. The power rating of the furnace is 2850 kW.

Microstructural evolution during the homogenization heat treatment of 6XXX and 7XXX aluminum alloys

Science.gov (United States)

Priya, Pikee

Homogenization heat treatment of as-cast billets is an important step in the processing of aluminum extrusions. Microstructural evolution during homogenization involves elimination of the eutectic morphology by spheroidisation of the interdendritic phases, minimization of the microsegregation across the grains through diffusion, dissolution of the low-melting phases, which enhances the surface finish of the extrusions, and precipitation of nano-sized dispersoids (for Cr-, Zr-, Mn-, Sc-containing alloys), which inhibit grain boundary motion to prevent recrystallization. Post-homogenization cooling reprecipitates some of the phases, changing the flow stress required for subsequent extrusion. These precipitates, however, are deleterious for the mechanical properties of the alloy and also hamper the age-hardenability and are hence dissolved during solution heat treatment. Microstructural development during homogenization and subsequent cooling occurs both at the length scale of the Secondary Dendrite Arm Spacing (SDAS) in micrometers and dispersoids in nanometers. Numerical tools to simulate microstructural development at both the length scales have been developed and validated against experiments. These tools provide easy and convenient means to study the process. A Cellular Automaton-Finite Volume-based model for evolution of interdendritic phases is coupled with a Particle Size Distribution-based model for precipitation of dispersoids across the grain. This comprehensive model has been used to study the effect of temperature, composition, as-cast microstructure, and cooling rates during post-homogenization quenching on microstructural evolution. The numerical study has been complimented with experiments involving Scanning Electron Microscopy, Energy Dispersive Spectroscopy, X-Ray Diffraction and Differential Scanning Calorimetry and a good agreement has with numerical results has been found. The current work aims to study the microstructural evolution during

Thermal Aging of Unsaturated Polyester Composite Reinforced with E-Glass Nonwoven Mat

Directory of Open Access Journals (Sweden)

Hossain Milon

2017-12-01

Full Text Available An experiment was carried out using glass fiber (GF as reinforcing materials with unsaturated polyester matrix to fabricate composite by hand layup technique. Four layers of GF were impregnated by polyester resin and pressed under a load of 5 kg for 20 hours. The prepared composite samples were treated by prolonged exposure to heat for 1 hour at 60-150°C and compared with untreated GF-polyester composite. Different mechanical test of the fabricated composite were investigated. The experiment depicted significant improvement in the mechanical properties of the fabricated composite resulted from the heat treatment. The maximum tensile strength of 200.6 MPa is found for 90°C heat-treated sample. The mechanical properties of the composite do seem to be very affected negatively above 100°C. Water uptake of the composite was carried out and thermal stability of the composite was investigated by thermogravimetric analysis, and it was found that the composite is stable up to 600°C. Fourier transform infrared spectroscopy shows the characteristic bond in the composite. Finally, the excellent elevated heat resistant capacity of glass-fiber-reinforced polymeric composite shows the suitability of its application to heat exposure areas such as kitchen furniture materials, marine, and electric board.

Modelling of volumetric composition and mechanical properties of unidirectional hemp/epoxy composites - Effect of enzymatic fibre treatment

DEFF Research Database (Denmark)

Liu, Ming; Thygesen, Anders; Meyer, Anne S.

2016-01-01

The objective of the present study is to assess the effect of enzymatic fibre treatments on the fibre performance in unidirectional hemp/epoxy composites by modelling the volumetric composition and mechanical properties of the composites. It is shown that the applied models can well predict...... the changes in volumetric composition and mechanical properties of the composites when differently treated hemp fibres are used. The decrease in the fibre correlated porosity factor with the enzymatic fibre treatments shows that the removal of pectin by pectinolytic enzymes results in a better fibre...

Properties of simulated welded joints of Cr-Mo steel following heat treatment in intercritical temperature range

International Nuclear Information System (INIS)

Sabun, L.B.; Vornovitskij, I.N.; Lukicheva, S.V.; Melamed, S.Eh.

1975-01-01

The parameters are determined of the welded joints heat treatment which permit to shorten the holp-up period due to the accelerating the process of the weld-stress release and the diffusion of carbon and alloying elements resulting in the equilibration of the weld metal chemical composition. The properties of an imitated welded joint of the 15KHM steel have been studied after various modes of heat treatment. The critical points are 740 and 875 deg C. The mechanical properties determination and the study of the strain hardening process are carried out with a high-temperature metallography plant. The modes of a low-temperature tempering and incomplete annealing are investigated within an intercritical range at temperatures of 750 to 780 deg C and a hold-up periods of to five minutes with a consecutive cooling in air or with the furnace respectively. The results of the studies have shown that with the decrease in the heat treatment temperature the strength, plasticity and also hardness of the welded joint zones prove to be to the standard of a sample treated conforming to the high tempering mode. In case of an incomplete annealing (770 to 780 deg C) the strength of the welded joint is maintained to the standard of the strength obtained at the high tempering, and the relative elongation value increases considerably at all the hold-up periods investigated. The strain-hardening process for the low-temperature normalizing and high tempering proceeds approximately equally. The fracture occurs at the deformation of 30 to 35% in microvolume, the relative elongation in that case being 12 to 13%

Effects of Mead Wort Heat Treatment on the Mead Fermentation Process and Antioxidant Activity.

Science.gov (United States)

Czabaj, Sławomir; Kawa-Rygielska, Joanna; Kucharska, Alicja Z; Kliks, Jarosław

2017-05-14

The effects of mead wort heat treatment on the mead fermentation process and antioxidant activity were tested. The experiment was conducted with the use of two different honeys (multiflorous and honeydew) collected from the Lower Silesia region (Poland). Heat treatment was performed with the use of a traditional technique (gently boiling), the more commonly used pasteurization, and without heat treatment (control). During the experiment fermentation dynamics were monitored using high performance liquid chromatography with refractive index detection (HPLC-RID). Total antioxidant capacity (TAC) and total phenolic content (TPC) were estimated for worts and meads using UV/Vis spectrophotometric analysis. The formation of 5-hydroxymethylfurfural (HMF) was monitored by HPLC analyses. Heat treatment had a great impact on the final antioxidant capacity of meads.

Development of the heat treatment system for the 40 T hybrid magnet superconducting outsert.

Science.gov (United States)

Chen, W G; Chen, Z M; Chen, Z Y; Huang, P C; He, P; Zhu, J W

2011-10-01

The heat treatment of Nb(3)Sn coil with the glass fabric insulation is one of the key and critical processes for the outsert solenoids of the 40 T hybrid magnet, which could be wound with cable-in-conduit conductors using the insulation-wind-and-react technique. The manufacturing of the large vertical type vacuum/Ar atmosphere-protection heat treatment system has been completed and recently installed in the High Magnetic Filed Laboratory, Chinese Academy of Sciences. The heat treatment system composed mainly the furnace, the purging gas supply system, the control system, the gas impurities monitoring system, and so on. At present, the regulation and testing of the heat treatment system has been successfully finished, and all of technical parameters meet or exceed specifications.

Influence of fuel composition on the non-oxidizing heating of steel in a waste gas atmosphere

Energy Technology Data Exchange (ETDEWEB)

Minkler, W [LOI Industrieofenanlagen G.m.b.H., Essen (Germany, F.R.)

1979-04-01

On the basis of a number of graphs and data on theoretical combustion temperatures and the difference between the heating value of the fuel and the waste gas in respect of 1 m/sup 3/ of waste gas, the author demonstrates the influence of fuel composition on the non-oxidizing heating of steel in a waste gas atmosphere derived from five different fuels. A rotary-hearth furnace is described for the non-oxidizing heating of pressings from plain carbon and alloy steel.

Microstructure and mechanical properties of reactor pressure vessel mock-up material treated by intercritical heat treatment

International Nuclear Information System (INIS)

Kim, M. C.; Lee, B. S.; Hong, J. H.; Lee, H. J.; Park, S. D.; Kim, K. B.; Yoon, J. H.; Kim, J. S.; Oh, J. M.

2003-12-01

The mechanical properties and microstructures of base metal and weld HAZ (Heat-Affected Zone) of a Mn-Mo-Ni low alloy steels treated by intercritical heat treatment were investigated to evaluate effects of intercritical heat treatment on mechanical properties. In order to clarify the effects of intercritical heat treatment, two types of specimen were prepared by CHT(Conventional Heat Treatment) and IHT(CHT+Intercritical Heat Treatment). Tensile test, charpy impact test and vickers hardness test were carried out to evaluate the mechanical properties. It is found that impact toughness and hardness were improved by intercritical heat treatment. Mean size of precipitates and effective grain were quantitatively analysed as microstructural factors. It is found that precipitate size was decreased and shape of precipitate was spherodized by intercritical heat treatment and grain size was also decreased. So, it is thought that these microstructural changes cause the improvement of mechanical properties by intercritical heat treatment. The simulated specimen using a Gleeble thermal simulator system was used to evaluate the mechanical properties of HAZ. It is well known that IRHAZ and SRHAZ have lower toughness than base metal. However, in the case of IHT, impact toughness of IRHAZ and SRHAZ were slightly higher than that of base metal. It is obvious that this improvement of fracture toughness in IRHAZ and SRHAZ region was closely related to the microstructural changes, such as spheroidization of precipitate and decreases of precipitate size and grain size

THE HEAT TREATMENT ANALYSIS OF E110 CASE HARDENING STEEL

Directory of Open Access Journals (Sweden)

MAJID TOLOUEI-RAD

2016-03-01

Full Text Available This paper investigates mechanical and microstructural behaviour of E110 case hardening steel when subjected to different heat treatment processes including quenching, normalizing and tempering. After heat treatment samples were subjected to mechanical and metallographic analysis and the properties obtained from applying different processes were analysed. The heat treatment process had certain effects on the resultant properties and microstructures obtained for E110 steel which are described in details. Quenching produced a martensitic microstructure characterized by significant increase in material’s hardness and a significant decreased in its impact energy. Annealed specimens produced a coarse pearlitic microstructure with minimal variation in hardness and impact energy. For normalized samples, fine pearlitic microstructure was identified with a moderate increase in hardness and significant reduction in impact energy. Tempering had a significant effect on quenched specimens, with a substantial rise in material ductility and reduction of hardness with increasing tempering temperature. Furthermore, Results provide additional substantiation of temper embrittlement theory for low-carbon alloys, and indicate potential occurrence of temper embrittlement for fine pearlitic microstructures.

UV-Heat Treatments for the Control of Foodborne Microbial Pathogens in Chicken Broth

Directory of Open Access Journals (Sweden)

M. Gouma

2015-01-01

Full Text Available This investigation established the process criteria for using UV-C light and mild heat (UV-H treatment to inactivate 5-Log10 cycles (performance criterion of common foodborne pathogen populations, Escherichia coli, Salmonella Typhimurium, Listeria monocytogenes, and Staphylococcus aureus, when inoculated in chicken broth. To define the target microorganism and the proper UV-H treatment conditions (including UV dose, treatment time, and temperature that would achieve the stated performance criterion, mathematical equations based on Geeraerd’s model were developed for each microorganism. For the sake of comparison, inactivation equations for heat treatments were also performed on the same chicken broth and for the same microorganisms. L. monocytogenes was the most UV-H resistant microorganism at all temperatures, requiring a UV dose between 6.10 J/mL (5.6 min and 2.26 J/mL (2.09 min to achieve 5-Log10 reductions. In comparison with UV treatments at room temperatures, the combination of UV and mild heat allowed both the UV dose and treatment time to be reduced by 30% and 63% at 55°C and 60°C, respectively. Compared to heat treatments, the UV-H process reduced the heating time for 5-Log10 reductions of all the investigated microorganisms in chicken broth from 20-fold to 2-fold when the operating temperature varied from 53 to 60°C.

Study of critical dependence of stable phases in Nitinol on heat treatment using electrical resistivity probe

International Nuclear Information System (INIS)

Uchil, J.; Mohanchandra, K.P.; Kumara, K.G.; Mahesh, K.K.

1998-01-01

Phase transformations in 40% cold-worked Nitinol as a function of heat treatment have been studied using electrical resistivity variation with temperature. The stabilisation of austenitic, rhombohedral and martensitic phases is shown to critically depend on the temperatures of heat treatment by the analysis of temperature dependence of electrical resistivity in heating and cooling parts of the cycle. Characteristic values of electrical resistivity of the stable phases are determined. The R-phase has been found to form continuously with increasing heat-treatment temperature starting from room temperature and to suddenly disappear beyond heat-treatment at 683 K. The observed presence or absence of R-phase is confirmed by heat capacity measurements as a function of temperature. (orig.)

Modeling heat and mass transfer in the heat treatment step of yerba maté processing

Directory of Open Access Journals (Sweden)

J. M. Peralta

2007-03-01

Full Text Available The aim of this research was to estimate the leaf and twig temperature and moisture content of yerba maté branches (Ilex paraguariensis Saint Hilaire during heat treatment, carried out in a rotary kiln dryer. These variables had to be estimated (modeling the heat and mass transfer due to the difficulty of experimental measurement in the dryer. For modeling, the equipment was divided into two zones: the flame or heat treatment zone and the drying zone. The model developed fit well with the experimental data when water loss took place only in leaves. In the first zone, leaf temperature increased until it reached 135°C and then it slowly decreased to 88°C at the exit, despite the gas temperature, which varied in this zone from 460°C to 120°C. Twig temperature increased in the two zones from its inlet temperature (25°C up to 75°C. A model error of about 3% was estimated based on theoretical and experimental data on leaf moisture content.

Effects of Heat-treatments on the Mechanical Strength of Coated YSZ: An Experimental Assessment

DEFF Research Database (Denmark)

Toftegaard, Helmuth Langmaack; Sørensen, Bent F.; Linderoth, Søren

2009-01-01

The mechanical strength of thin, symmetric sandwich specimens consisting of a dense yttria-stabilized zirconia (YSZ) substrate coated with a porous NiO–YSZ layer at both major faces was investigated. Specimens were loaded in uniaxial tension to failure following heat treatments at various...... temperatures. In comparison with the YSZ material, the failure strength of coated specimens was found to increase for heat treatments at 1100°C, but decreased again with further increased heat-treatment temperatures....

Influence of Heat Treatment on Mercury Cavitation Resistance of Surface Hardened 316LN Stainless Steel

Energy Technology Data Exchange (ETDEWEB)

Pawel, Steven J [ORNL; Hsu, Julia [Massachusetts Institute of Technology (MIT)

2010-11-01

The cavitation-erosion resistance of carburized 316LN stainless steel was significantly degraded but not destroyed by heat treatment in the temperature range 500-800 C. The heat treatments caused rejection of some carbon from the carburized layer into an amorphous film that formed on each specimen surface. Further, the heat treatments encouraged carbide precipitation and reduced hardness within the carburized layer, but the overall change did not reduce surface hardness fully to the level of untreated material. Heat treatments as short as 10 min at 650 C substantially reduced cavitation-erosion resistance in mercury, while heat treatments at 500 and 800 C were found to be somewhat less detrimental. Overall, the results suggest that modest thermal excursions perhaps the result of a weld made at some distance to the carburized material or a brief stress relief treatment will not render the hardened layer completely ineffective but should be avoided to the greatest extent possible.

Uninterrupted heat-treatment of starch raw materials

Energy Technology Data Exchange (ETDEWEB)

Bronshtein, D Z

1958-01-01

A setup is presented, with a Rekord grinder, a Khronos scale, and other equipment of Soviet manufacture, in which oats, rye, wheat, and other grains are treated at 42 to 45 degrees prior to their use as raw materials in the ethanol industry. These materials are analyzed with respect to H/sub 2/O, starch, bulk, weight, screen analysis, and the final ethanol yields/ton of such raw materials. In a three year run in plant, this heat-treatment was advantageous, as compared to the former treatment of the starch materials.

Uninterrupted heat-treatment of starch raw materials

Energy Technology Data Exchange (ETDEWEB)

Bronshtein, D Z

1958-01-01

A setup is presented, with a Rekord grinder, a Khronos scale, and other equipment of Soviet manufacture, in which oats, rye, wheat, and other grains are treated at 42 to 45/sup 0/ prior to their use as raw materials in the ethanol industry. These materials are analyzed with respect to H/sub 2/O, starch, bulk weight, screen analysis, and the final ethanol yields/ton of such raw materials. In a three year run in a plant, this heat-treatment was advantageous, as compared to the former treatment of the starch materials.

Design of heat treatments for 9-12%Cr steels to optimise creep resistance for power plant applications

Energy Technology Data Exchange (ETDEWEB)

Morris, P.F.; Sachadel, U.A.; Clarke, P.D. [Tata Steel Europe, Rotherham (United Kingdom). Swinden Technology Centre; CRD and T, IJmuiden (Netherlands)

2010-07-01

Optimisation of the creep rupture properties of Steel 92 (9%Cr, 0.5%Mo, 2%W) by modification of heat treatment and C:N ratio has been studied. It was shown that a higher austenization temperature and double tempering at lower temperature can significantly extend creep life of the standard composition. The increase in austenization temperature from 1060 C and double tempering at 660 C/3h instead of single tempering at 780 C/2h resulted in the increase of stress rupture life from 1,734 to 6,179h at 650 C/110MPa. Even greater improvement in creep life was achieved by the combination of the modified heat treatment and decreased C:N ratio. In this case the creep life was extended to 10,255 h at 650 C/110MPa. A further increase in austenitization temperature to 1200 C for the decreased C:N ratio variant extended the rupture life to 17,118h. Initial results indicate that this modified heat treatment schedule does not result in notch brittle behaviour and most of the improvement in creep strength remains after a simulated post weld heat treatment at 740 C. The stress rupture programme is continuing and at 600 C test durations are approaching 60,000h. To explain the effect on rupture life thermodynamic calculations, microscopic investigations and a literature study were performed. Electron metallography investigations revealed that the lower tempering temperature resulted in a finer distribution of nano-size particles. Calculations show that increasing the austenitization temperature gave more dissolved B, N, C, Nb and V. The lower C:N ratio resulted in a higher atomic fraction of N in nano-size particles on subsequent tempering. Dissolved B should stabilize M{sub 23}M{sub 6} and dissolved N, C, Nv, and V should allow precipitation of a higher volume fraction of nano-size carbo-nitrides during tempering. Literature data suggest that lower tempering temperatures could also change their type from MX to M{sub 2}X. (orig.)

The effect of heat treatment on phosphorus segregation in a submerged-arc weld metal

International Nuclear Information System (INIS)

Beere, W.B.; Buswell, J.T.

1999-01-01

Intergranular fracture (IGF) has been observed in carbon-manganese steels after irradiation or high temperature exposure for prolonged periods. The effect is associated with an increase in the ductile-brittle transition temperature and has been related to phosphorus diffusion to grain boundaries. Phosphorus also diffuses thermally at the temperatures used for post-weld heat treatments such that in principle, the slightly different heat treatments given to different parts of a large vessel could lead to differing grain boundary phosphorus coverage and hence susceptibility to IGF. The effect of typical heat treatments on phosphorus coverage has been investigated using a finite difference model based on a theory that has been fitted to a wide range of constant temperature data. Regardless of previous history, the grain boundary coverage of phosphorus was predicted to depend on the final anneal and cooling rate. These differed insufficiently in the typical heat treatments to produce significant differences in segregation. It was concluded that the ductile-brittle transition temperature in submerged-arc welds would be unaffected in vessels that had seen typical post-weld heat treatments

Unique effects of microwave heating on polymerization kinetics of poly(methyl methacrylate) composites

Energy Technology Data Exchange (ETDEWEB)

Spasojević, Pavle [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11120 Belgrade (Serbia); Jovanović, Jelena, E-mail: jelenaj@ffh.bg.ac.rs [Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11001 Belgrade (Serbia); Adnadjevic, Borivoj [Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11001 Belgrade (Serbia)

2013-09-16

The effects of heating mode (conventional and microwave) on the kinetics of isothermal polymerization of MMA composite materials were investigated. Isothermal kinetics curves at temperature range from 343 K to 363 K for both conventional (CH) and microwave heating (MWH) were determined. It was found that the polymerization of MMA composite materials was kinetically elementary reaction for both CH and MWH. The kinetics of CH polymerization can be described by the model of phase-boundary controlled process (contracting volume), whereas the kinetics of MWH polymerization can be described by the model of first-order chemical reaction. The kinetics parameters (E{sub a} and ln A) of the polymerization under microwave heating are lower than for conventional heating. The established decreases in the activation energy and pre-exponential factor under the MWH compared to the CH is explained with the increase in the energy of ground vibrational level of the C–O valence vibrations (ν = 987 cm{sup −1}) in methyl methacrylate molecule and with the decrease in its anharmonicity factor which is caused with the selective resonant transfer of energy from the energetic reservoir to the oscillators in methyl methacrylate molecules. - Graphical abstract: Display Omitted - Highlights: • The MWH speeds the MMA material polymerization and changes the kinetics model. • A novel concept of MWH action based on activation complexes formation is presented. • The Selective Energy Transfer model is used to explain the effects of MWH. • The kinetics parameters under MWH are lower than for CH. • The activation energy for both MWH and CH polymerization is quantized.

TiC-Maraging stainless steel composite: microstructure, mechanical and wear properties

Institute of Scientific and Technical Information of China (English)

Akhtar Farid; GUO Shiju; FENG Peizhong; Khadijah Ali Shah; Syed Javid Askari

2006-01-01

Particulate TiC reinforced 17-4PH and 465 maraging stainless steel matrix composites were processed by conventional powder metallurgy (P/M). TiC-maraging stainless steel composites with theoretical density ＞97% were produced using conventional P/M. The microstructure, and mechanical and wear properties of the composites were evaluated. The microstructure of the composites consisted of (core-rim structure) spherical and semi-spherical TiC particles depending on the wettability of the matrix with TiC particles. In TiC-maraging stainless steel composites, 465 stainless steel binder phase showed good wettability with TiC particles. Some microcracks appeared in the composites, indicating the presence of tensile stresses in the composites produced during sintering. The typical properties, hardness, and bend strength were reported for the composites. After heat treatment and aging, an increase in hardness was observed. The increase in hardness was attributed to the aging reaction in maraging stainless steel. The specific wear behavior of the composites strongly depends on the content of TiC particles and their interparticle spacing, and on the heat treatment of the maraging stainless steel.

Effect of heat treatment upon the fatigue-crack growth behavior of Alloy 718 weldments

International Nuclear Information System (INIS)

James, L.A.; Mills, W.J.

1981-05-01

Gas-tungsten-arc weldments in Alloy 718 were studied in fatigue-crack growth test conducted at five temperatures over the range 24--649 degree C. In general, crack growth rates increased with increasing temperature, and weldments given the ''conventional'' post-weld heat-treatment generally exhibited crack growth rates that were higher than for weldments given the ''modified'' (INEL) heat-treatment. Limited testing in the as-welded condition revealed crack growth rates significantly lower than observed for the heat-treated cases, and this was attributed to residual stresses. Three different heats of filler wire were utilized, and no heat-to-heat variations were noted. 23 refs., 9 figs., 6 tabs

Effect of heat treatment temperature on microstructure

Indian Academy of Sciences (India)

The results of electrochemical performance measurements for the HCSs as anode material for lithium ion batteries indicate that the discharge capacity of the HCSs is improved after heat treatment at 800°C compared with the as-prepared HCSs and have a maximum value of 357 mAh/g and still retains 303 mAh/g after 40 ...

Numerical analysis of heat treatment of TiCN coated AA7075 aluminium alloy

Science.gov (United States)

Srinath, M. K.; Prasad, M. S. Ganesha

2018-04-01

The Numerical analysis of heat treatments of TiCN coated AA7075 aluminium alloys is presented in this paper. The Convection-Diffusion-Reaction (CDR) equation with solutions in the Streamlined-Upward Petrov-Galerkin (SUPG) method for different parameters is provided for the understanding of the process. An experimental process to improve the surface properties of AA-7075 aluminium alloy was attempted through the coatings of TiCN and subsequent heat treatments. From the experimental process, optimized temperature and time was obtained which gave the maximum surface hardness and corrosion resistance. The paper gives an understanding and use of the CDR equation for application of the process. Expression to determine convection, diffusion and reaction parameters are provided which is used to obtain the overall expression of the heat treatment process. With the substitution of the optimized temperature and time, the governing equation may be obtained. Additionally, the total energy consumed during the heat treatment process is also developed to give a mathematical formulation of the energy consumed.

Application of C/C composites to the combustion chamber of rocket engines. Part 1: Heating tests of C/C composites with high temperature combustion gases

Science.gov (United States)

Tadano, Makoto; Sato, Masahiro; Kuroda, Yukio; Kusaka, Kazuo; Ueda, Shuichi; Suemitsu, Takeshi; Hasegawa, Satoshi; Kude, Yukinori

1995-04-01

Carbon fiber reinforced carbon composite (C/C composite) has various superior properties, such as high specific strength, specific modulus, and fracture strength at high temperatures of more than 1800 K. Therefore, C/C composite is expected to be useful for many structural applications, such as combustion chambers of rocket engines and nose-cones of space-planes, but C/C composite lacks oxidation resistivity in high temperature environments. To meet the lifespan requirement for thermal barrier coatings, a ceramic coating has been employed in the hot-gas side wall. However, the main drawback to the use of C/C composite is the tendency for delamination to occur between the coating layer on the hot-gas side and the base materials on the cooling side during repeated thermal heating loads. To improve the thermal properties of the thermal barrier coating, five different types of 30-mm diameter C/C composite specimens constructed with functionally gradient materials (FGM's) and a modified matrix coating layer were fabricated. In this test, these specimens were exposed to the combustion gases of the rocket engine using nitrogen tetroxide (NTO) / monomethyl hydrazine (MMH) to evaluate the properties of thermal and erosive resistance on the thermal barrier coating after the heating test. It was observed that modified matrix and coating with FGM's are effective in improving the thermal properties of C/C composite.

Effect of heat treatment on the grooving corrosion resistance of ERW pipes

International Nuclear Information System (INIS)

Lee, Jong Kwon; Lee, Jae Young; Lim, Soo Hyun; Park, Ji Hwan; Seo, Bo Min; Kim, Seon Hwa

2002-01-01

The v-sharp grooving corrosion of ERW(electrical resistance welding) steel pipes limited their wide application in the industry in spite of their high productivity and efficiency. The grooving corrosion is caused mainly by the different microstructures between the matrix and weld that is formed during the rapid heating and cooling cycle in welding. By this localized corrosion reaction of pipes, it evolves economic problems such as the early damage of industrial facilities and pipe lines of apartment, and water pollution. Even though the diminishing of sulfur content is most effective to decrease the susceptibility of grooving corrosion, it requires costly process. In this study, improvement of grooving corrosion resistance was pursuited by post weld heat treatment in the temperature range between 650 .deg. C and 950 .deg. C. Also, the effect of heat input in the welding was investigated. By employing chromnoamperometry and potentiodynamic experiment, the corrosion rate and grooving corrosion index(α) were obtained. It was found that heat treatment could improve the grooving corrosion resistance. Among them, the heat treated at 900 .deg. C and 950 .deg. C had excellent grooving corrosion resistance. The index of heat treated specimen at 900 .deg. C and 950 .deg. C were 1.0, 1.2, respectively, which are almost immune to the grooving corrosion. Potential difference after the heat treatment, between base and weld metal was decreased considerably. While the as-received one measured 61∼71 mV, that of the 900 .deg. C heat treated steel pipe measured only 10mV. The results were explained and discussed

Heat cascading regenerative sorption heat pump

Science.gov (United States)

Jones, Jack A. (Inventor)

1995-01-01

A simple heat cascading regenerative sorption heat pump process with rejected or waste heat from a higher temperature chemisorption circuit (HTCC) powering a lower temperature physisorption circuit (LTPC) which provides a 30% total improvement over simple regenerative physisorption compression heat pumps when ammonia is both the chemisorbate and physisorbate, and a total improvement of 50% or more for LTPC having two pressure stages. The HTCC contains ammonia and a chemisorbent therefor contained in a plurality of canisters, a condenser-evaporator-radiator system, and a heater, operatively connected together. The LTPC contains ammonia and a physisorbent therefor contained in a plurality of compressors, a condenser-evaporator-radiator system, operatively connected together. A closed heat transfer circuit (CHTC) is provided which contains a flowing heat transfer liquid (FHTL) in thermal communication with each canister and each compressor for cascading heat from the HTCC to the LTPC. Heat is regenerated within the LTPC by transferring heat from one compressor to another. In one embodiment the regeneration is performed by another CHTC containing another FHTL in thermal communication with each compressor. In another embodiment the HTCC powers a lower temperature ammonia water absorption circuit (LTAWAC) which contains a generator-absorber system containing the absorbent, and a condenser-evaporator-radiator system, operatively connected together. The absorbent is water or an absorbent aqueous solution. A CHTC is provided which contains a FHTL in thermal communication with the generator for cascading heat from the HTCC to the LTAWAC. Heat is regenerated within the LTAWAC by transferring heat from the generator to the absorber. The chemical composition of the chemisorbent is different than the chemical composition of the physisorbent, and the absorbent. The chemical composition of the FHTL is different than the chemisorbent, the physisorbent, the absorbent, and ammonia.

Preparation and thermal properties of form-stable palmitic acid/active aluminum oxide composites as phase change materials for latent heat storage

International Nuclear Information System (INIS)

Fang, Guiyin; Li, Hui; Cao, Lei; Shan, Feng

2012-01-01

Form-stable palmitic acid (PA)/active aluminum oxide composites as phase change materials were prepared by adsorbing liquid palmitic acid into active aluminum oxide. In the composites, the palmitic acid was used as latent heat storage materials, and the active aluminum oxide was used as supporting material. Fourier transformation infrared spectroscope (FT-IR), X-ray diffractometer (XRD) and scanning electronic microscope (SEM) were used to determine the chemical structure, crystalloid phase and microstructure of the composites, respectively. The thermal properties and thermal stability were investigated by a differential scanning calorimeter (DSC) and a thermogravimetry analyzer (TGA). The FT-IR analyses results indicated that there is no chemical interaction between the palmitic acid and active aluminum oxide. The SEM results showed that the palmitic acid was well adsorbed into porous network of the active aluminum oxide. The DSC results indicated that the composites melt at 60.25 °C with a latent heat of 84.48 kJ kg −1 and solidify at 56.86 °C with a latent heat of 78.79 kJ kg −1 when the mass ratio of the PA to active aluminum oxide is 0.9:1. Compared with that of the PA, the melting and solidifying time of the composites CPCM5 was reduced by 20.6% and 21.4% because of the increased heat transfer rate through EG addition. The TGA results showed that the active aluminum oxide can improve the thermal stability of the composites. -- Highlights: ► Form-stable PA/active aluminum oxide composites as PCMs were prepared. ► Chemical structure, crystalloid phase and microstructure of composites were determined. ► Thermal properties and thermal stability of the composites were investigated. ► Expanded graphite can improve thermal conductivity of the composites.

Heat Treatment Effect on Eu3+ Doped TeO2-BaO-Bi2O3 Glass Systems with Ag Nanoparticles

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Tomasz Lewandowski

2017-01-01

Full Text Available Glass systems of 73TeO2-4BaO-3Bi2O3-2Eu2O3-xAg (in molar ratio where x = 0, 1, 2, and 3 compositions have been successfully synthesized. Silver nanoparticles were obtained with the employment of heat treatment (HT procedure executed at 350°C. Glass transition temperatures of different compositions have been determined through DSC measurements. XRD results presented characteristic amorphous halo indicating lack of long range order in the samples. FTIR structural studies revealed that glass matrix is mainly composed of TeO3 and TeO4 species and is stable after different applied heat treatment times. X-ray photoelectron spectroscopy (XPS measurements confirmed that in selected samples part of Ag ions changed oxidation state to form Ag0 species. TEM measurements revealed nanoparticles of size in the range of 20–40 nm. UV-vis absorption results demonstrated characteristic transitions of Eu3+ ions. Additionally, UV-vis spectra of samples heat-treated for 6, 12, 24, and 48 hours presented bands related to silver nanoparticles. Photoluminescence (PL studies have been performed with excitation wavelength of λexc=395 nm. Obtained spectra exhibited peaks due to 5D0-7FJ (where J=2,3,4 and 5D1-7FJ (where J=1,2,3 transitions of Eu3+. Moreover, luminescence measurement indicated enhancement of rare earth ions emissions in several of the annealed samples. Increase of emission intensity of about 35% has been observed.

THE EFFECT OF HEAT TREATMENT ON THE DURABILITY OF BAMBOO Gigantochloa scortechinii

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Norashikin Kamarudin

2012-07-01

Full Text Available Bamboo signifies as one of the fastest growing plants and it can be used for various products. In tropical countries such as Indonesia and Malaysia, bamboo is abundantly available at reasonable prices, therefore it is used for numerous purposes. However, as lignocellulosic material, bamboo is susceptible to fungal and insect attacks. Heat treatment is an option to improve bamboo's durability. The objective of this study was to improve the durability of bamboo using hot oil palm treatment. A Malaysian grown bamboo species, Buluh Semantan (Gigantochloa scortechinii, as a study material was soaked in hot oil palm for various temperatures and soaking time, before being inoculated with the basidiomycete Coriolus versicolor in an agar block test. The results demonstrated that the longer the heating time, the more improved the durability of bamboo. Altering the temperature in the palm oil treatment produced varying results. Bamboo blocks that heated in hot oil palm at 100°C for 60 minutes shows considerably less weight eduction that indicates less fungal attack. Overall, the higher the temperature, the better the durability of bamboo. Please indicates what the meaning of heat treatment in this experiment, it is not clear.

Effects of Polypropylene Orientation on Mechanical and Heat Seal Properties of Polymer-Aluminum-Polymer Composite Films for Pouch Lithium-Ion Batteries

Directory of Open Access Journals (Sweden)

Fangxinyu Zeng

2018-01-01

Full Text Available In this study, polyamide-aluminum foil-polypropylene (PA-Al-PP composite films with different orientation status of the PP layer were prepared, and their morphology, tensile, peeling and heat seal behavior were studied. The comparative study of tensile and fracture behaviors of single-layer film of PA, Al and PP, as well as the composite films of PA-Al, PP-Al and PA-Al-PP revealed that in PA-Al-PP composite film, the PA layer with the highest tensile strength can share the tensile stress from the Al layer during stretching, while the PP layer with the lowest tensile strength can prevent further development of the small cracks on boundary of the Al layer during stretching. Moreover, the study of heat seal behavior suggested that both the orientation status and the heat seal conditions were important factors in determining the heat seal strength (HSS and failure behavior of the sample. Four failure types were observed, and a clear correspondence between HSS and failure types was found. The results also elucidated that for the composite film, only in the cases where the tensile stress was efficiently released by each layer during HSS measurement could the composite film exhibit desired high HSS that was even higher than its tensile strength.

Effects of heat treatment and welding process on superelastic behaviour and microstructure of micro electron beam welded NiTi

Directory of Open Access Journals (Sweden)

Balz Isabel

2016-09-01

Full Text Available Medical devices with small dimensions made of superelastic NiTi become more popular, but joining these parts remains challenging. Since laser welding was found to be an option, electron beam welding seems to be an interesting alternative as it provides additional advantages due to the precise beam positioning and the high vacuum. Superelasticity is influenced by microstructure and surface layer composition that are mainly affected by welding process and by heat treatment and therefore will be investigated in the present paper.

Surface development of a brazing alloy during heat treatment-a comparison between UHV and APXPS

Science.gov (United States)

Rullik, L.; Johansson, N.; Bertram, F.; Evertsson, J.; Stenqvist, T.; Lundgren, E.

2018-01-01

In an attempt to bridge the pressure gap, APXPS was used to follow the surface development of an aluminum brazing sheet during heating in an ambient oxygen-pressure mimicking the environment of an industrial brazing furnace. The studied aluminum alloy brazing sheet is a composite material consisting of two aluminum alloy standards whose surface is covered with a native aluminum oxide film. To emphasize the necessity of studies of this system in ambient sample environments it is compared to measurements in UHV. Changes in thickness and composition of the surface oxide were followed after heating to 300 °C, 400 °C, and 500 °C. The two sets presented in this paper show that the surface development strongly depends on the environment the sample is heated in.

Residual stress measurements by X-ray and neutron diffractions in heat-treated SiCw/A2014 composites

International Nuclear Information System (INIS)

Ohnuki, Takahisa; Fujita, Motoo; Tomota, Yo; Ono, Masayoshi

1998-01-01

Residual stresses due to various heat treatments in a 22 volume percent SiC whisker/A2014 metal matrix composite (MMC) were measured by using X-ray and neutron diffractions. Micro residual stresses generated from the differences in thermal expansion coefficients of the constituents and macro residual stresses associated with different cooling rates in the outer and inner regions of an MMC specimen must be distinguished in X-ray stress measurements. The conventional sin 2 ψ method under an assumption of plane stress condition has been found not to be applicable to the present MMC, because interactions among whiskers in the X-ray penetrating area yields σ 33 where the x 3 -axis is normal with respect to specimen's surface. An average value of σ 33 can be measured by X-ray diffraction technique, but does not seem enough to evaluate micro residual stresses. It is found that neutron diffraction is the most powerful method to measure micro residual stresses in the constituents. Elastic residual strains obtained by neutron diffraction in solution treated or T6 heat treated samples show good agreements with predictions calculated by using Eshelby inclusion theory coupled with the Mori-Tanaka mean field concept, indicating that the influence of stress relaxation is negligible. In addition, internal stresses relaxations during holding at room temperature, slow cooling from solution treatment temperature, or subzero cooling are discussed. (author)

Effect of Graphene Coating on the Heat Transfer Performance of a Composite Anti-/Deicing Component

Directory of Open Access Journals (Sweden)

Long Chen

2017-09-01

Full Text Available The thermal conductivity of a graphene coating for anti-/deicing is rarely studied. This paper presents an improved anti-/deicing efficiency method for composite material anti-/deicing by using the heat-transfer characteristic of a graphene coating. An anti-/deicing experiment was conducted using the centrifugal force generated by a helicopter rotor. Results showed that the graphene coating can accelerate the internal heat transfer of the composite material, thereby improving the anti-icing and deicing efficiency of the helicopter rotor. The spraying process parameters, such as coating thickness and spraying pressure, were also studied. Results showed that reducing coating thickness and increasing spraying pressure are beneficial in preparing a graphene coating with high thermal conductivity. This study provides an experimental reference for the application of a graphene coating in anti-/deicing.

Reactions of lactose during heat treatment of milk : a quantitative study

NARCIS (Netherlands)

Berg, H.E.

1993-01-01

The kinetics of the chemical reactions of lactose during heat treatment of milk were studied. Skim milk and model solutions resembling milk were heated. Reaction products were determined and the influence of varying lactose, casein and fat concentration on the formation of these products

Investigation of heat treatment conditions of structural material for blanket fabrication process

International Nuclear Information System (INIS)

Hirose, Takanori; Suzuki, Satoshi; Akiba, Masato; Shiba, Kiyoyuki; Sawai, Tomotsugu; Jitsukawa, Shiro

2004-01-01

This paper presents recent results of thermal hysteresis effects on ceramic breeder blanket structural material. Reduced activation ferritic/martensitic (RAF) steel is the leading candidates for the first wall structural materials of breeding blankets. RAF steel demonstrates superior resistance to high dose neutron irradiation, because the steel has tempered martensite structure which contains the number of sink site for radiation defects. This microstructure obtained by two-step heat treatment, first is normalizing at temperature above 1200 K and the second is tempering at temperature below 1100 K. Recent study revealed the thermal hysteresis has significant impacts on the post-irradiation mechanical properties. The breeding blanket has complicated structure, which consists of tungsten armor and thin first wall with cooling pipe. The blanket fabrication requires some high temperature joining processes. Especially hot isostatic pressing (HIP) is examined as a near-net-shape fabrication process for this structure. The process consists of heating above 1300 K and isostatic pressing at the pressure above 150 MPa followed by tempering. Moreover ceramics pebbles are packed into blanket module and the module is to be seamed by welding followed by post weld heat treatment in the final assemble process. Therefore the final microstructural features of RAFs strongly depend on the blanket fabrication process. The objective of this work is to evaluate the effects of thermal hysteresis corresponding to blanket fabrication process on RAFs microstructure in order to establish appropriate blanket fabrication process. Japanese RAFs F82H (Fe-0.1C-8Cr-2W-0.2V-0.05Ta) was investigated by metallurgical method after isochronal heat treatment up to 1473 K simulating high temperature bonding process. Although F82H showed significant grain growth after conventional solid HIP conditions (1313 K x 2 hr.), this coarse grained microstructure was refined by the post HIP normalizing at

Experimental and numerical study of heat transfer performance of nitrate/expanded graphite composite PCM for solar energy storage

International Nuclear Information System (INIS)

Xiao, X.; Zhang, P.; Li, M.

2015-01-01

Highlights: • Thermal conductivity of nitrate/EG composite was accurately measured by considering thermal contact resistance. • Heat storage and retrieval tests were conducted with binary nitrates and nitrates/EG composites. • A comprehensive model was built to interpret the heat transfer characteristics. - Abstract: Eutectic molten salt can be used as the latent thermal energy storage medium in solar energy applications. Nitrates and their binary mixtures are suitable phase change material (PCM) for solar energy applications in middle-temperature-range of 200–300 °C. In the present study, binary nitrate (50 wt.% NaNO_3, 50 wt.% KNO_3) with a melting temperature of about 220 °C was employed as the PCM, and expanded graphite (EG) with the mass fraction of 5%, 10% or 20% was used to enhance the thermal conductivity. The thermal conductivities of pure nitrates and nitrate/EG shape-stabilized composites were measured with a steady-state test rig firstly. Results showed that the addition of EG significantly enhanced the thermal conductivities, e.g., the thermal conductivities of sodium nitrate/20 wt.% EG composite PCM were measured to be 6.66–7.70 W/(m K) in the temperature range of 20–120 °C, indicating about seven times larger than those of pure sodium nitrate. Furthermore, pure binary nitrate and nitrate/EG composite PCM were encapsulated in a cylindrical storage unit with a diameter of 70.0 mm and a length of 280.0 mm. Heat storage and retrieval tests were conducted extensively at different heating temperatures of 250 °C, 260 °C and 270 °C, and different cooling temperatures of 30 °C, 70 °C and 110 °C. Time-durations from temperature evolutions showed that both the melting and solidification processes were accelerated by EG, and the heat transfer characteristics were interpreted by the numerical analysis based on enthalpy–porosity and volume-of-fluid models. The evolution of nitrate/air interface caused by volume expansion ascended gradually

Heat transfer characteristics of thermal energy storage of a composite phase change materials: Numerical and experimental investigations

International Nuclear Information System (INIS)

Aadmi, Moussa; Karkri, Mustapha; El Hammouti, Mimoun

2014-01-01

In the present study, phase change materials based on epoxy resin paraffin wax with the melting point 27 °C were used as a new energy storage system. Thermophysical properties and the process of melting of a PCM (phase change material) composite were investigated numerically and experimentally. DSC (differential scanning calorimetry) has been used for measurement of melting enthalpy and determination of PCM heat capacity. The thermophysical properties of the prepared composite have been characterized by using a new transient hot plate apparatus. The results have shown that the most important thermal properties of these composites at the solid and liquid states are like the “apparent” thermal conductivity, the heat storage capacity and the latent heat of fusion. These experimental results have been simulated by using numerical Comsol ® Multiphysiques 4.3 based models with success. The results of the experimental investigation compare favorably with the numerical results and thus serve to validate the numerical approach. - Highlights: • Phase change materials based on paraffin spheres used as new energy storage system. • Thermophysical properties and the melting process of composites were investigated. • All experimental results have been simulated using Comsol ® Multiphysiques. • The ability to store and release the thermal energy were investigated. • A very thin molten PCM (phase change material) exists which is apparently visible in the spheres

Effect of Cold Drawing and Heat Treatment on the Microstructure of Invar36 Alloy Wire

International Nuclear Information System (INIS)

Han, Seung Youb; Jang, Seon Ah; Eun, Hee-Chul; Choi, Jung-Hoon; Lee, Ki Rak; Park, Hwan Seo; Ahn, Do-Hee; Kim, Soo Young; Kim, Jea Youl; Shin, Sang Yong

2016-01-01

In this study, the effect of cold drawing and heat treatment on the microstructure of Invar36 alloy wire was investigated. Invar36 alloy wire is used as a transmission line core material, and is required to have high strength. The diameter of the Invar36 alloy wire specimens were reduced from 16 mm to 4.3 mm after three cold drawing and two heat treatment processes, thereby increasing tensile strength. Specimens were taken after each of the cold drawing and heat treatment processes, and their microstructure and tensile properties were analyzed. The Invar36 alloy wire had a γ-(Fe, Ni) phase matrix before the cold drawing and heat treatment processes. After the cold drawing processes, {220} and {200} textures were mainly achieved. After the heat treatment processes, a {200} recrystallization γ-(Fe, Ni) phase was formed with fine carbides. The recrystallization γ-(Fe, Ni) phase grains had low dislocation density, so they probably accommodated a large amount of deformation during the cold drawing processes.

Effect of Cold Drawing and Heat Treatment on the Microstructure of Invar36 Alloy Wire

Energy Technology Data Exchange (ETDEWEB)

Han, Seung Youb; Jang, Seon Ah; Eun, Hee-Chul; Choi, Jung-Hoon; Lee, Ki Rak; Park, Hwan Seo; Ahn, Do-Hee [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Soo Young; Kim, Jea Youl [RandD Center, KOS Ltd., Yangsan (Korea, Republic of); Shin, Sang Yong [University of Ulsan, Ulsan (Korea, Republic of)

2016-10-15

In this study, the effect of cold drawing and heat treatment on the microstructure of Invar36 alloy wire was investigated. Invar36 alloy wire is used as a transmission line core material, and is required to have high strength. The diameter of the Invar36 alloy wire specimens were reduced from 16 mm to 4.3 mm after three cold drawing and two heat treatment processes, thereby increasing tensile strength. Specimens were taken after each of the cold drawing and heat treatment processes, and their microstructure and tensile properties were analyzed. The Invar36 alloy wire had a γ-(Fe, Ni) phase matrix before the cold drawing and heat treatment processes. After the cold drawing processes, {220} and {200} textures were mainly achieved. After the heat treatment processes, a {200} recrystallization γ-(Fe, Ni) phase was formed with fine carbides. The recrystallization γ-(Fe, Ni) phase grains had low dislocation density, so they probably accommodated a large amount of deformation during the cold drawing processes.

A comparative effect of various surface chemical treatments on the resin composite-composite repair bond strength

Directory of Open Access Journals (Sweden)

Shaloo Gupta

2015-01-01

Full Text Available Aim: The aim of this in vitro study was an attempt to investigate the effect of different surface treatments on the bond strength between pre-existing composite and repair composite resin. Materials and Methods: Forty acrylic blocks were prepared in a cuboidal mould. In each block, a well of 5 mm diameter and 5 mm depth was prepared to retain the composite resin (Filtek™ Z350, 3M/ESPE. Aging of the composite discs was achieved by storing them in water at 37°C for 1 week, and after that were divided into 5 groups (n = 8 according to surface treatment: Group I- 37% phosphoric acid, Group II-10% hydrofluoric acid, Group III-30% citric acid, Group IV-7% maleic acid and Group V- Adhesive (no etchant. The etched surfaces were rinsed and dried followed by application of bonding agent (Adper™ Single Bond 2. 3M/ESPE. The repair composite was placed on aged composite, light-cured for 40 seconds and stored in water at 37°C for 1 week. Shear bond strength between the aged and the new composite resin was determined with a universal testing machine (crosshead speed of 0.5 mm/min. Statistical Analysis: The compressive shear strengths were compared for differences using ANOVA test followed by Tamhane′s T2 post hoc analysis. Results: The surface treatment with 10% hydrofluoric acid showed the maximum bond strength followed by 30% citric acid, 7% maleic acid and 37% phosphoric acid in decreasing order. Conclusion: The use of 10% hydrofluoric acid can be a good alternative for surface treatment in repair of composite resin restoration as compared to commonly used 37% orthophosphoric acid.

Effect of grinding and heat treatment on the mechanical behavior of zirconia ceramic

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Gabriela Freitas RAMOS

2016-01-01

Full Text Available Abstract The present study investigated the effect of grinding on roughness, flexural strength, and reliability of a zirconia ceramic before and after heat treatment. Seven groups were tested (n = 15: a control group (labeled CG, untreated, and six groups of samples ground with diamond discs, simulating diamond burs, with grits of 200 µm (G80; 160 µm (G120, and 25 µm (G600, either untreated or heat-treated at 1200°C for 2 h (labeled A. Yttria tetragonal zirconia polycrystal discs were manufactured, ground, and submitted to roughness and crystalline phase analyses before the biaxial flexural strength test. There was no correlation between roughness (Ra and Rz and flexural strength. The reliability of the materials was not affected by grinding or heat treatment, but the characteristic strength was higher after abrasion with diamond discs, irrespective of grit size. The X-ray diffraction data showed that grinding leads to a higher monoclinic (m phase content, whereas heat treatment produces reverse transformation, leading to a fraction of m-phase in ground samples similar to that observed in the control group. However, after heat treatment, only the G80A samples presented strength similar to that of the control group, while the other groups showed higher strength values. When zirconia pieces must be adjusted for clinical use, a smoother surface can be obtained by employing finer-grit diamond burs. Moreover, when the amount of monoclinic phase is related to the degradation of zirconia, the laboratory heat treatment of ground pieces is indicated for the reverse transformation of zirconia crystals.

Effect of Pressure and Heat Treatments on the Compressive Strength of Reactive Powder Concrete

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Helmi Masdar

2018-01-01

Full Text Available This paper presents the corresponding compressive strength of RPC with variable pressure combined with heating rate, heating duration, and starting time of heating. The treatments applied were 8 MPa static pressure on fresh RPC prims and heat curing at 240 °C in an oven. The compressive strength test was conducted at 7-d and 28-d. The images of RPC morphology were captured on the surface of a fractured specimen using Scanning Electron Microscopy in Secondary Electron detector mode to describe pore filing mechanism after treatments. The results show that a heating rate at 50 °C/hr resulted in the highest compressive strength about 40 % more than those at 10 or 100 °C/hr. A heating duration of 48 hours led to the maximum compressive strength. Heat curing applied 2 days after casting resulted in the maximum compressive. Heat curing had a signicant effect on the compresssive strength due to the acceleration of both reactions (hydration and pozzolanic and the degree of transformation from tobermorite to xonotlite. It is concluded that the optimum condition of treatments is both pressure and heat curing at 2-day after casting with a rate of 50 °C/hr for 48 hours.

Effect of heat treatment regime on structural lamination in ferritic-austenitic steels

International Nuclear Information System (INIS)

Sizov, R.A.; Zakharova, M.I.; Novikov, I.I.; Bannykh, O.A.

1983-01-01

The effect of preliminary thermal treatment on lamination and viscosity of EhP-53 and KO-3 steels after durable aging at the temperature of 350 is studied. It is shown that preliminary heat treatment considerably affects lamination processes in the result of aging of 0Kh18G8N2T steel. The lowest rate of lamination and higher impact strength after aging at 350 deg C for 4500 hours corresponds to the following heat treatment: 10 hour aging at 650 deg C with cooling in the air, then quenching in water from 950 deg C after aging for 30 min and the following tempering (650 deg C, 5 hours). Unlike the 0Kh18G8N2T steel, lamination parameters of steel 0Kh22N6T practically do not change after the application of heat treatment. Nevertherless, taking into account results of impact strength, it is advisable to have thermal treatment according to the regime: quenching in water at 950 deg C after aging for 30 min

Effect of Heat Treatment on the Lycopene Content of Tomato Puree ...

African Journals Online (AJOL)

Effect of Heat Treatment on the Lycopene Content of Tomato Puree. MI Mohammed, DI Malami. Abstract. Lycopene is a powerful antioxidant. Epidemiological studies have associated its consumption with numerous health benefits. In this study the effects of heating on lycopene were investigated by exposing tomato ...

Effect of heat treatment duration on tribological behavior of electroless Ni-(high)P coatings

Science.gov (United States)

Biswas, A.; Das, S. K.; Sahoo, P.

2016-09-01

Electroless nickel coating occurs through an autocatalytic chemical reaction and without the aid of electricity. From tribological perspective, it is recommended due to its high hardness, wear resistance, lubricity and corrosion resistance properties. In this paper electroless Ni-P coatings with high phosphorous weight percentages are developed on mild steel (AISI 1040) substrates. The coatings are subjected to heat treatment at 300°C and 500°C for time durations up to 4 hours. The effect of heat treatment duration on the hardness as well as tribological properties is discussed in detail. Hardness is measured in a micro hardness tester while the tribological tests are carried out on a pin-on-disc tribotester. Wear is reported in the form of wear rates of the sample subjected to the test. As expected, heat treatment of electroless Ni-P coating results in enhancement in its hardness which in turn increases its wear resistance. The present study also finds that duration of heat treatment has quite an effect on the properties of the coating. Increase in heat treatment time in general results in increase in the hardness of the coating. Coefficient of friction is also found to be lesser for the samples heat treated for longer durations (4 hour). However, in case of wear, similar trend is not observed. Instead samples heat treated for 2 to 3 hour display better wear resistance compared to the same heat treated for 4 hour duration. The microstructure of the coating is also carried out to ensure about its proper development. From scanning electron microscopy (SEM), the coating is found to possess the conventional nodular structure while energy dispersive X-ray analysis (EDX) shows that the phosphorous content in the coating to be greater than 9%. This means that the current coating belongs to the high phosphorous category. From X-ray diffraction analysis (XRD), it is found that coating is amorphous in as-deposited condition but transforms into a crystalline structure with

Flexible and stable heat energy recovery from municipal wastewater treatment plants using a fixed-inverter hybrid heat pump system

International Nuclear Information System (INIS)

Chae, Kyu-Jung; Ren, Xianghao

2016-01-01

Highlights: • Specially designed fixed-inverter hybrid heat pump system was developed. • Hybrid operation performed better at part loads than single inverter operation. • The applied heat pump can work stably over a wide range of heat load variations. • Heat energy potential of treated effluent was better than influent. • The heat pump’s COP from the field test was 4.06 for heating and 3.64 for cooling. - Abstract: Among many options to improve energy self-sufficiency in sewage treatment plants, heat extraction using a heat pump holds great promise, since wastewater contains considerable amounts of thermal energy. The actual heat energy demand at municipal wastewater treatment plants (WWTPs) varies widely with time; however, the heat pumps typically installed in WWTPs are of the on/off controlled fixed-speed type, thus mostly run intermittently at severe part-load conditions with poor efficiency. To solve this mismatch, a specially designed, fixed-inverter hybrid heat pump system incorporating a fixed-speed compressor and an inverter-driven, variable-speed compressor was developed and tested in a real WWTP. In this hybrid configuration, to improve load response and energy efficiency, the base-heat load was covered by the fixed-speed compressor consuming relatively less energy than the variable-speed type at nominal power, and the remaining varying load was handled by the inverter compressor which exhibits a high load-match function while consuming relatively greater energy. The heat pump system developed reliably extracted heat from the treated effluent as a heat source for heating and cooling purposes throughout the year, and actively responded to the load changes with a high measured coefficient of performance (COP) of 4.06 for heating and 3.64 for cooling. Moreover, this hybrid operation yielded a performance up to 15.04% better on part loads than the single inverter operation, suggesting its effectiveness for improving annual energy saving when

Effect of heat treatment on antimycotic activity of Sahara honey

Directory of Open Access Journals (Sweden)

Moussa Ahmed

2014-11-01

Full Text Available Objective: To evaluate the influence of the temperature on honey colour, polyphenol contents and antimycotic capacity and to evaluate the correlation between these parameters. Methods: Sahara honey were heated up to 25, 50, 75 and 100 °C for 15, 30 and 60 min, and their colour intensity, polyphenol contents and antimycotic capacity. The Folin-Ciocalteu test was used to determine the total polyphenol contents (TPC. The antimycotic activity was evaluated both by agar diffusion method and micro wells dilution method against the Candida albicans (C. albicans and Candida glabrata (C. glabrata. Results: Initial values for TPC in Sahara honey ranged from 0.55 to 1.14 mg of gallic acid per kg of honey, with the average value of 0.78 mg of gallic acid per kg of honey. The TPC values after heat-treatment were 0.54 to 1.54 with the average value of 1.49 mg. The minimal inhibitory concentrations before heat-treatment of Sahara honey against C. albicans and C. glabrata ranged from 3.06%-12.5% and 50% respectively. After heat-treatment the minimal inhibitory concentrations between 12.5% and 50% for C. albicans and C. glabrata, respectively. The diameters of inhibition zones of Sahara honey with 50% concentration varied from (12.67-15.00 mm by C. albicans to (14.33-15.67 mm by C. glabrata. The diameters of inhibition zones after heat-treatment at 25 and 50 °C for 15.30 and 60 min ranged from (2.00-18.67 mm by C. albicans to (8.00-16.67 mm by C. glabrata. Statistically significant relations between the TPC and the colour intensity of Sahara honey (r=0.99, P<0.05. Furthermore, the results showed that the TPC and colour is not correlated with the antimycotic capacity. Conclusions: To our knowledge this is the first report on the antimycotic capacity of Sahara honey.

Effect of heat treatment duration on phase separation of sodium borosilicate glass, containing copper

International Nuclear Information System (INIS)

Shejnina, T.G.; Gutner, S.Kh.; Anan'in, N.I.

1989-01-01

The effect of heat treatment duration on phase separation of sodium borosilicate (SBS) glass, containing copper is studied. It is stated that phase separation close to equilibrium one is attained under 12 hours of heat treatment of SBS glass containing copper

Local total and radiative heat-transfer coefficients during the heat treatment of a workpiece in a fluidised bed

International Nuclear Information System (INIS)

Gao, W.M.; Kong, L.X.; Hodgson, P.D.

2006-01-01

The heat-transfer coefficients around a workpiece immersed in an electrically heated heat treatment fluidised bed were studied. A suspension probe designed to simulate a workpiece of complex geometry was developed to measure local total and radiative heat-transfer coefficients at a high bed temperature. The probe consisted of an energy-storage region separated by insulation from the fluidised bed, except for the measuring surface, and a multi-thermocouple measurement system. Experiments in the fluidised bed were performed for a fluidising medium of 120-mesh alumina, a wide temperature range of 110-1050 deg. C and a fluidising number range of 1.18-4.24. It was found that the workpiece surface temperature has a more significant effect on heat transfer than the bed temperature. The total heat-transfer coefficient at the upper surface of the workpiece sharply decreased at the start of heating, and then steadily increased as heating progressed, while a sharp decrease became a rapid increase and then a slow increase for the radiative heat-transfer coefficient. A great difference in the heat-transfer coefficients around the workpiece was observed

Microbial safety control of compost material with cow dung by heat treatment.

Science.gov (United States)

Gong, Chun-ming

2007-01-01

Various kinds of pathogenic bacteria derived from the intestinal tract of animals exist in compost material like cow dung. In order to sterilize the pathogenic bacteria completely in compost material, the cow dung was put into a heat treatment machine in pilot plan, and harmless condition in short time was examined. The results indicated, pathogenic indicator bacteria such as coliform bacteria, fecal coliform, Escherichia coli and salmonella were all 106 cfu/g dw at the beginning, died rapidly when cow dung temperature rose to above 50 degrees C, and not detected at 54-68 degrees C for 6-24 h heat treatment. Coliform bacteria and salmonella in heated cow dung were not detected by re-growth culture and enrichment culture examination. Moreover, it was hardly influenced on the fermentation ability of composting microbe, organic decomposition bacteria. During heat treatment, the mesophile decreased rapidly and the thermophile stabilized or increased, and the most of composting microbe were bacillus in cow dung by fluorescence microscope, this indicated that bacillus was dominator and composting microbe in composting process.

Influence of Heat Treatments on Carotenoid Content of Cherry Tomatoes

Directory of Open Access Journals (Sweden)

Laura D'Evoli

2013-07-01

Full Text Available Tomatoes and tomato products are rich sources of carotenoids—principally lycopene, followed by β-carotene and lutein. The aim of this work was to study the effect of heat treatment on carotenoid content in cherry tomatoes. Raw and canned products were sampled and analysed; furthermore whole, skin and pulp fractions of cherry tomatoes were analysed when raw and home-processed, in order to better understand heat treatment effects. Lycopene content in canned tomatoes was two-fold higher than in raw tomatoes (11.60 mg/100 g versus 5.12 mg/100 g. Lutein and β-carotene were respectively 0.15 mg/100 g and 0.75 mg/100 g in canned tomatoes versus 0.11 mg/100 g and 1.00 mg/100 g in raw tomatoes. For home-processed tomatoes, β-carotene and lutein showed a content decrease in all thermally treated products. This decrease was more evident for β-carotene in the skin fraction (−17%, while for lutein it was greater in the pulp fraction (−25%. Lycopene presented a different pattern: after heat treatment its concentration increased both in the whole and in pulp fractions, while in the skin fraction it decreased dramatically (−36%. The analysis of the isomers formed during the thermal treatment suggests that lycopene is rather stable inside the tomato matrix.

Influence of Heat Treatments on Carotenoid Content of Cherry Tomatoes.

Science.gov (United States)

D'Evoli, Laura; Lombardi-Boccia, Ginevra; Lucarini, Massimo

2013-07-31

Tomatoes and tomato products are rich sources of carotenoids-principally lycopene, followed by β-carotene and lutein. The aim of this work was to study the effect of heat treatment on carotenoid content in cherry tomatoes. Raw and canned products were sampled and analysed; furthermore whole, skin and pulp fractions of cherry tomatoes were analysed when raw and home-processed, in order to better understand heat treatment effects. Lycopene content in canned tomatoes was two-fold higher than in raw tomatoes (11.60 mg/100 g versus 5.12 mg/100 g). Lutein and β-carotene were respectively 0.15 mg/100 g and 0.75 mg/100 g in canned tomatoes versus 0.11 mg/100 g and 1.00 mg/100 g in raw tomatoes. For home-processed tomatoes, β-carotene and lutein showed a content decrease in all thermally treated products. This decrease was more evident for β-carotene in the skin fraction (-17%), while for lutein it was greater in the pulp fraction (-25%). Lycopene presented a different pattern: after heat treatment its concentration increased both in the whole and in pulp fractions, while in the skin fraction it decreased dramatically (-36%). The analysis of the isomers formed during the thermal treatment suggests that lycopene is rather stable inside the tomato matrix.

The influence of distal-end heat treatment on deflection of nickel-titanium archwire.

Science.gov (United States)

Silva, Marcelo Faria da; Pinzan-Vercelino, Célia Regina Maia; Gurgel, Júlio de Araújo

2016-01-01

The aim of this in vitro study was to evaluate the deflection-force behavior of nickel-titanium (NiTi) orthodontic wires adjacent to the portion submitted to heat treatment. A total of 106 segments of NiTi wires (0.019 x 0.025-in) and heat-activated NiTi wires (0.016 x 0.022-in) from four commercial brands were tested. The segments were obtained from 80 archwires. For the experimental group, the distal portion of each segmented archwire was subjected to heat treatment (n = 40), while the other distal portion of the same archwire was used as a heating-free control group (n = 40). Deflection tests were performed in a temperature-controlled universal testing machine. Unpaired Student's t-tests were applied to determine if there were differences between the experimental and control groups for each commercial brand and size of wire. Statistical significance was set at p wire. Heat treatment applied to the distal ends of rectangular NiTi archwires does not permanently change the elastic properties of the adjacent portions.

Effect of nitrite on the microbiological stability of canned Vienna sausages preserved by mild heat treatment or combinations of heat and irradiation

International Nuclear Information System (INIS)

Farkas, J.; Zukal, E.; Incze, K.

1973-01-01

Keeping quality of Vienna sausages packed in No. 1/5 cans (ca 200 g) with salt brine and heat treated with F 0 values in the range of 0.25-0.55 was studied as a function of sodium nitrate addition. In uninoculated cans the heat requirement of preservation proved to be about 0.3 F 0 in the presence of 300 ppm NaNO 2 . A heat treatment of 0.55 F 0 and 200 ppm NaNO 2 resulted in higher microbiological stability of cans inoculated with 2x10 4 /tin Clostridium sporogenes spores than a heat treatment of 1.9 F 0 without nitrite addition. The effect of the combination of heat treatment of 0.35-0.55 F 0 and 0.45 Mrad of gamma irradiation was also studied with inoculated cans. The combination of irradiation plus heat resulted in a higher microbiological stability of the samples than the reversed order of the treatments, but this synergistic effect could not be proved in all experiments. The addition of 200 ppm NaNO 2 was not as effective in increasing the shelf-life of combination treated samples as with the solely heat treated ones. In a medium composed of a 50% extract of Vienna sausages (pH 6.4, asub(w) 0.96) and inoculated with 10 5 per ml Clostridium sporogenes spores 100 ppm or more NaNO 2 was required to ensure microbiological stability of samples heat treated with F 0 0.4. In the range of the permitted concentration level for canned meat products, sodium nitrite did not influence the heat resistance of Clostridium sporogenes, but inhibited the germination of the surviving spores. (F.J.)

The effect of post-weld heat treatment temperature on the microstructure of Inconel 625 deposited metal

International Nuclear Information System (INIS)

Xing, Xixue; Di, Xinjie; Wang, Baosen

2014-01-01

Highlights: • Post-weld heat treatment effects on microstructure of deposited metal are studied. • Coarsening of γ′ phase at different post-weld heat treatment temperature is revealed. • Formation of δ phase in deposited metal is a bainite-like transformation process. - Abstract: The effect of post-weld heat treatment (PWHT) temperatures on the microstructure of Inconel 625 deposited metal (DM) was examined using an optical microscope (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The transformation mechanism of the γ ″ → δ phase and the grain growth kinetics of the γ′ phase during PWHT were revealed. The results indicate that the microstructure of as-welded DM is composed of columnar grains of different sizes, of which the average grain size is approximately 160 μm. Certain precipitates, such as the dispersed γ′ phase, blocky MC-type carbide and irregular shape Laves phase, precipitate in the microstructure of the as-welded DM. Compared with as-welded DM, the microstructure of DM after PWHT at 650 °C for 4 h shows minimal variation. With an increase in PWHT temperature, a large number of body-centered tetragonal γ ″ phases precipitate at interdendrite regions in the microstructure of DM after PWHT at 750 °C for 4 h. When the PWHT temperature increases to 850 °C, the metastable γ ″ phase directly transforms into a stable δ phase in shear mode, which exhibits a similar chemical composition but a different crystal structure than the γ ″ phase. At 950 °C, the γ ″ phase and the δ phase disappear, whereas certain M 6 C-type carbides precipitate at the grain boundaries. Alloying elements such as Nb, Mo, Si, Al and Fe in the microstructure of as-welded DM exhibit segregation behavior. Due to an increasing PWHT temperature, the segregation behavior constantly weakens with minimal evolution to the temperature of 750 °C. Above this temperature, partition coefficients tend toward 1, and

The effect of post-weld heat treatment temperature on the microstructure of Inconel 625 deposited metal

Energy Technology Data Exchange (ETDEWEB)

Xing, Xixue [Tianjin Key Laboratory of Advanced Joining Technology, Tianjin University, No.92 Weijin Road, Nankai District, Tianjin 300072 (China); Di, Xinjie, E-mail: dixinjie@tju.edu.cn [Tianjin Key Laboratory of Advanced Joining Technology, Tianjin University, No.92 Weijin Road, Nankai District, Tianjin 300072 (China); Wang, Baosen [Baosteel Research Institute, Baoshan Iron and Steel Co., Ltd., Baoshan District, Shanghai 200431 (China)

2014-04-01

Highlights: • Post-weld heat treatment effects on microstructure of deposited metal are studied. • Coarsening of γ′ phase at different post-weld heat treatment temperature is revealed. • Formation of δ phase in deposited metal is a bainite-like transformation process. - Abstract: The effect of post-weld heat treatment (PWHT) temperatures on the microstructure of Inconel 625 deposited metal (DM) was examined using an optical microscope (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The transformation mechanism of the γ{sup ″} → δ phase and the grain growth kinetics of the γ′ phase during PWHT were revealed. The results indicate that the microstructure of as-welded DM is composed of columnar grains of different sizes, of which the average grain size is approximately 160 μm. Certain precipitates, such as the dispersed γ′ phase, blocky MC-type carbide and irregular shape Laves phase, precipitate in the microstructure of the as-welded DM. Compared with as-welded DM, the microstructure of DM after PWHT at 650 °C for 4 h shows minimal variation. With an increase in PWHT temperature, a large number of body-centered tetragonal γ{sup ″} phases precipitate at interdendrite regions in the microstructure of DM after PWHT at 750 °C for 4 h. When the PWHT temperature increases to 850 °C, the metastable γ{sup ″} phase directly transforms into a stable δ phase in shear mode, which exhibits a similar chemical composition but a different crystal structure than the γ{sup ″} phase. At 950 °C, the γ{sup ″} phase and the δ phase disappear, whereas certain M{sub 6}C-type carbides precipitate at the grain boundaries. Alloying elements such as Nb, Mo, Si, Al and Fe in the microstructure of as-welded DM exhibit segregation behavior. Due to an increasing PWHT temperature, the segregation behavior constantly weakens with minimal evolution to the temperature of 750 °C. Above this temperature, partition coefficients

Influence of heat treatment on physicochemical and rheological characteristics of natural yogurts