The Experts below are selected from a list of 189 Experts worldwide ranked by ideXlab platform
Aysegül Dere - One of the best experts on this subject based on the ideXlab platform.
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The effect of e/a ratio on thermodynamic parameters and surface morphology of Cu–Al–Fe–X shape memory alloys
Journal of Thermal Analysis and Calorimetry, 2019Co-Authors: Canan Aksu Canbay, Sivar Aziz, İskender Özkul, Aysegül DereAbstract:In this study, four Cu–Al–Fe–X shape memory alloys were produced by the arc melting technique, and the martensitic transformation temperatures, thermodynamic parameters, and the activation energy values were obtained. The activation energy values of the alloys were calculated as 666.36, 401.6, 82.94, and 226.22 kJ mol−1 for S1, S2, S3, and S4, respectively. High-temperature phase transitions and Eutectoid Point of the samples were examined by the differential thermal analysis method. The martensitic diffraction planes of the samples were found as 122, 0022, 1210, and 2012, and the crystallite size of the samples was calculated as 16.21, 20.20, 14.43, and 17.46, respectively. Lastly, optical micrograph observations revealed the morphology of the alloys and the variations in the grains and martensite structures. The e/a ratio of the alloys varied 1.47–1.51, and these values are in agreement with the values in literature to give shape memory effect.
Xiang Zhao - One of the best experts on this subject based on the ideXlab platform.
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Effects of High Magnetic Field Heat Treatment on the Microstructure of Fe-0.76%C Alloy
Materials Science Forum, 2011Co-Authors: Ming Long Gong, Xiang Zhao, Chang Shu He, J.y. SongAbstract:The present studies are to investigate the microstructure features during transformation from austenite to ferrite without and with magnetic field on Fe-0.76%C alloy. It is found that the area fraction and numbers of proEutectoid ferrite grain as well as the lamellar spacing of pearlite in Fe-0.76%C alloy increased considerably with the increase of magnetic field intensity. The reason is that, the magnetic field increases the driving force of proEutectoid ferrite nuclei and shifts the Eutectoid Point to the side of high carbon content and high temperature, which increases the starting-temperature of the transformation from austenite to ferrite. The proEutectoid ferrite grains are elongated along the magnetic field direction, which can be explained as follows: the proEutectoid ferrite becomes the magnetic dipolar under high magnetic field, and then the polarized austenite atoms are much easier to diffuse into ferrite grains along the magnetic field direction. Key words: high magnetic field; Fe-0.76%C alloy; microstructure
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effect of a high magnetic field on Eutectoid Point shift and texture evolution in 0 81c fe steel
Texture Stress and Microstructure, 2008Co-Authors: Yudong Zhang, Claude Esling, Marion Calcagnotto, M L Gong, H Klein, Xiang ZhaoAbstract:A 12 T magnetic field has been applied to the annealing process of a 0.81%C-Fe (wt.%). It is found that the magnetic field shifts the Eutectoid carbon content from 0.77 wt.% to 0.83 wt.%. The statistical thermodynamic calculations were performed to calculate the Eutectoid temperature change by the magnetic field. Calculation shows that the increase of the Eutectoid temperature by a 12 T field is 29∘C. Synchrotron radiation measurements were performed to measure the pole figures of the samples and were analyzed by MAUD to determine the bulk texture of the ferrite phase In the field-treated and non field-treated samples. Results show that although there is no specific preferred orientation appearing by applying the magnetic field, slight enhancement of (001) fiber component occurs in both the sample normal direction (ND) and the transverse direction (TD). This effect might be related to the magnetic dipolar interaction between Fe atoms in the transverse field direction.
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shift of the Eutectoid Point in the fe c binary system by a high magnetic field
Journal of Physics D, 2007Co-Authors: Yikun Zhang, Claude Esling, Marion Calcagnotto, M L Gong, Xiang ZhaoAbstract:The purpose of this paper is to investigate experimentally the shift of the Eutectoid Point in the Fe–C binary system when applying a high magnetic field. The Eutectoid carbon content is observed to shift from 0.77 wt% to 0.83 wt% under a 12 T magnetic field. A practical and complete calculation method is proposed—on the basis of the statistical thermodynamic model—to calculate the Gibbs free energy of the related phases and predict the shift of the Eutectoid Point due to a magnetic field in both composition and temperature coordinates. The composition values are seen to be in fair agreement with the experimental data. The calculation of both shifts shows that the rise in Eutectoid temperature because of the 12 T field is 28.97 ◦ C. The impact of the magnetic field on both Eutectoid carbon content and Eutectoid temperature is not linear. The rate of the shift of both carbon content and temperature decreases as the magnetic field rises.
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Diffusion-Controlled Phase Transformation under High Magnetic Field in Medium and High Carbon Steels
Materials Science Forum, 2007Co-Authors: Yudong Zhang, Claude Esling, Xiang ZhaoAbstract:The new phase equilibrium of Fe-C diagram under magnetic field has been theoretically calculated. Results show that the magnetic field mainly shifts the γ⁄α+γ equilibrium line and the Eutectoid Point to the high carbon and high temperature sides. Based on this result, an experimental setup has been launched to investigate the effect of magnetic field on austenite decomposition in medium carbon and high carbon steels. The thermodynamic and kinetic effects of the high magnetic field on proEutectoid transformation at different cooling rates have been studied. It was found that for medium carbon steels, the magnetic field increases the amount of proEutectoid ferrite and accelerates the diffusional decomposition of austenite at medium and relatively fast cooling rates (10°C/min and 46°C/min). But there is no special grain growth along the field direction. The results led to a proposal of a new rapid annealing under a high magnetic field. However, when cooling is slow (2°C/min), the magnetic field shows a strong tendency to promote the proEutectoid ferrite grains to grow along the field direction through the magnetic dipolar interaction, which leads to the formation of an elongated grain structure. Moreover, the magnetic field also exhibits influence on the austenite decomposition in hyperEutectoid steel by changing the amount of secondary cementite and lamellar spacing of pearlite.
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Microstructural features induced by a high magnetic field in a hyperEutectoid steel during austenitic decomposition
Scripta Materialia, 2006Co-Authors: Yikun Zhang, Claude Esling, M L Gong, G. Vincent, Xiang ZhaoAbstract:Abstract A 12-T magnetic field was introduced during the austenitic decomposition of a high carbon steel at various cooling rates. It was found that the magnetic field applied can reduce the amount of proEutectoid cementite, increase the lamellar spacing of pearlite and decrease the frequencies of low angle misorientations in ferrite. The experimental results of this work prove the shift of the Eutectoid Point to high carbon side and high temperature side by the application of a magnetic field.
Canan Aksu Canbay - One of the best experts on this subject based on the ideXlab platform.
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The effect of e/a ratio on thermodynamic parameters and surface morphology of Cu–Al–Fe–X shape memory alloys
Journal of Thermal Analysis and Calorimetry, 2019Co-Authors: Canan Aksu Canbay, Sivar Aziz, İskender Özkul, Aysegül DereAbstract:In this study, four Cu–Al–Fe–X shape memory alloys were produced by the arc melting technique, and the martensitic transformation temperatures, thermodynamic parameters, and the activation energy values were obtained. The activation energy values of the alloys were calculated as 666.36, 401.6, 82.94, and 226.22 kJ mol−1 for S1, S2, S3, and S4, respectively. High-temperature phase transitions and Eutectoid Point of the samples were examined by the differential thermal analysis method. The martensitic diffraction planes of the samples were found as 122, 0022, 1210, and 2012, and the crystallite size of the samples was calculated as 16.21, 20.20, 14.43, and 17.46, respectively. Lastly, optical micrograph observations revealed the morphology of the alloys and the variations in the grains and martensite structures. The e/a ratio of the alloys varied 1.47–1.51, and these values are in agreement with the values in literature to give shape memory effect.
Yikun Zhang - One of the best experts on this subject based on the ideXlab platform.
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shift of the Eutectoid Point in the fe c binary system by a high magnetic field
Journal of Physics D, 2007Co-Authors: Yikun Zhang, Claude Esling, Marion Calcagnotto, M L Gong, Xiang ZhaoAbstract:The purpose of this paper is to investigate experimentally the shift of the Eutectoid Point in the Fe–C binary system when applying a high magnetic field. The Eutectoid carbon content is observed to shift from 0.77 wt% to 0.83 wt% under a 12 T magnetic field. A practical and complete calculation method is proposed—on the basis of the statistical thermodynamic model—to calculate the Gibbs free energy of the related phases and predict the shift of the Eutectoid Point due to a magnetic field in both composition and temperature coordinates. The composition values are seen to be in fair agreement with the experimental data. The calculation of both shifts shows that the rise in Eutectoid temperature because of the 12 T field is 28.97 ◦ C. The impact of the magnetic field on both Eutectoid carbon content and Eutectoid temperature is not linear. The rate of the shift of both carbon content and temperature decreases as the magnetic field rises.
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Microstructural features induced by a high magnetic field in a hyperEutectoid steel during austenitic decomposition
Scripta Materialia, 2006Co-Authors: Yikun Zhang, Claude Esling, M L Gong, G. Vincent, Xiang ZhaoAbstract:Abstract A 12-T magnetic field was introduced during the austenitic decomposition of a high carbon steel at various cooling rates. It was found that the magnetic field applied can reduce the amount of proEutectoid cementite, increase the lamellar spacing of pearlite and decrease the frequencies of low angle misorientations in ferrite. The experimental results of this work prove the shift of the Eutectoid Point to high carbon side and high temperature side by the application of a magnetic field.
Luis Reis - One of the best experts on this subject based on the ideXlab platform.
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Experimental characterization of the mechanical properties of railway wheels manufactured using class B material
Procedia structural integrity, 2020Co-Authors: Henrique Soares, T. Zucarelli, M. Vieira, Manuel Freitas, Luis ReisAbstract:Abstract The railway system has an important role in developed countries, it is possible to see, nowadays, passenger trains crossing the Old Continent and achieving impressive speeds in the East; at the same time, cargo wagons are hitting load-by-axle records in North America. Railway wheels are a critical component to this system, as any failure can lead to derailment, potentially causing financial loss and/or fatal accidents. The present work aims to analyze the mechanical properties of forged wheels manufactured according to the American standard AAR Class B (produced at the MWL Brasil facility), usually applied in passenger cars due its chemical composition (around the Eutectoid Point) which achieves high mechanical resistance combined with moderated toughness. The mechanical tests to evaluate the mechanical strength, ductility, fracture toughness and hardness were performed in accordance with the European standard BS EN 13262 (location of sample and method test), as follows: tensile tests, impact tests, toughness tests and hardness Brinell tests (hardness survey/hardness map). The results are in accordance with the microstructure and chemical composition, and will be employed in future investigations for the numerical validation of the mechanical behavior for multiaxial fatigue conditions and for failure analysis reports.
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Experimental characterization of the mechanical properties of railway wheels manufactured using class C material
Theoretical and Applied Fracture Mechanics, 2016Co-Authors: T. Zucarelli, Henrique Soares, M. Vieira, L.a. Moreira Filho, Luis ReisAbstract:Abstract The railway system has an important role in developed countries: it is possible to see, nowadays, passenger trains crossing the Old Continent and achieving impressive speeds in the East; at the same time, cargo wagons are hitting load-by-axle records in North America. Railway wheels are a critical component to this system, as any failure can lead to derailment, potentially causing financial loss and/or fatal accidents. The present work aims to analyze the mechanical properties of forged wheels manufactured according to the American standard AAR class C, usually applied in freight cars due its chemical composition (around the Eutectoid Point) which achieves high mechanical resistance combined with moderated toughness. The mechanical tests to evaluate the mechanical strength, ductility, toughness and hardness were performed in accordance with the European standard BS EN 13262, as follows: tensile tests at different temperatures, impact tests, toughness tests and hardness Brinell tests. The obtained results are in accordance with the microstructure and chemical composition of class C material, and will be employed in future investigations for the numerical validation of the mechanical behavior for multiaxial fatigue conditions and development of new materials (micro alloyed steel).
