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Influence of processing history on microstructure， mechanical properties， and electrical conductivity of Cu-0.7Mg alloy

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Transactions of Nonferrous Metals Society of China 2024年

作者： Alireza KALHOR Kinga RODAK Marek TKOCZ Bartosz CHMIELA Ivo SCHINDLER ?ukasz POLOCZEK Krzysztof RADWA?SKI hamed mirzadeh Marian KAMPIK Faculty of Materials Engineering Silesian University of Technology V?B – Technical University of Ostrava Faculty of Materials Science and Technology Materials Research Group ?ukasiewicz Upper Silesian Institute of Technology School of Metallurgy and Materials Engineering College of Engineering University of Tehran Faculty of Electrical Engineering Silesian University of Technology

The effects of forward extrusion as well as extrusion combined with reversible torsion (KoBo extrusion)， followed by additional deformation via the MaxStrain module of the Gleeble thermomechanical simulator， on the microstructure， mechanical properties， and electrical conductivity of a Cu-0.7Mg (wt.%) alloy， were investigated in this work. The simulation results highlighted the critical influence of processing history in determining the equivalent strain distribution. The sample subjected to forward extrusion at 400 ℃and subsequent MaxStrain processing (FM sample)， possessed 76% lower grain size compared to the sample processed solely with MaxStrain (AM sample). Likewise， the KoBo-extruded and MaxStrain-processed sample (KM sample) exhibited 66% smaller grain size compared to the AM sample. Tensile test results revealed that the AM， FM， and KM samples， respectively， possessed 251%， 288%， and 360% higher yield strength， and 95%， 121%， and 169% higher tensile strength compared to the initial annealed alloy， as a result of grain refinement as well as deformation strengthening. Finally， the electrical conductivity measurements revealed that AM， FM， and KM samples， respectively， possessed electrical conductivity values of 37.9， 35.6， and 32.0 (MS/m)， which， considering their mechanical properties， makes them eligible to be categorized as high-strength and high-conductivity copper alloys.

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Surface metal-matrix composites based on AZ91 magnesium alloy via friction stir processing:A review

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International Journal of Minerals,Metallurgy and Materials 2023年第7期30卷 1278-1296页

作者： hamed mirzadeh School of Metallurgy and Materials Engineering College of EngineeringUniversity of TehranTehranIran

This monograph presents an overview of friction stir processing(FSP)of surface metal-matrix composites(MMCs)using the AZ91 magnesium *** reported results in relation to various reinforcing particles,including silicon carbide(SiC),alumina(Al_(2)O_(3)),quartz(SiO_(2)),boron carbide(B_(4)C),titanium carbide(TiC),carbon fiber,hydroxyapatite(HA),in-situ formed phases,and hybrid reinforcements are ***91 composite fabricating methods based on FSP are explained,including groove filling(grooving),drilled hole filling,sandwich method,stir casting followed by FSP,and formation of in-situ *** effects of introducing second-phase particles and FSP process parameters(e.g.,tool rotation rate,traverse speed,and the number of passes)on the microstructural modification,grain refinement,homogeneity in the distribution of particles,inhibition of grain growth,mechanical properties,strength–ductility trade-off,wear/tribological behavior,and corrosion resistance are ***,useful suggestions for future work are proposed,including focusing on the superplasticity and superplastic forming,metal additive manufacturing processes based on friction stir engineering(such as additive friction stir deposition),direct FSP,stationary shoulder FSP,correlation of the dynamic recrystallization(DRX)grain size with the Zener–Hollomon parameter similar to hot deformation studies,process parameters(such as the particle volume fraction and external cooling),and common reinforcing phases such as zirconia(ZrO_(2))and carbon nanotubes(CNTs).

关键词： surface composites magnesium alloys friction stir processing severe plastic deformation thermomechanical processing

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Dependency of Deformation Behavior of Retained Austenite in TRIP Steels on Microstructural and Chemical Homogeneity

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Acta Metallurgica Sinica(English Letters) 2015年第10期28卷 1272-1277页

作者： Ghavam Azizi hamed mirzadeh Mohammad Habibi Parsa School of Metallurgy and Materials Engineering College of Engineering University of Tehran

The room-temperature stability of the retained austenite against strain-induced martensitic transformation, its deformation behavior, the response to the bainitic isothermal treatment, the appearance of yield point elongation and other peculiarities of plastic flow, and the mechanical properties of transformation-induced plasticity（TRIP） steel were tailored based on the chemical homogeneity and the relative distribution of the retained austenite, bainite, and ferrite in the microstructure. The presence of ferritic-pearlitic banded structure in the initial microstructure resulted in an inhomogeneous TRIP microstructure, in which the retained austenite and bainite were confined to some bands and it was found to be responsible for the resultant inferior mechanical properties. The appearance of discontinuous yielding for the chemically inhomogeneous material was related to the martensitic transformation of unstable retained austenite at the initial stage of tensile deformation. These results are essential for better understanding of the behavior of advanced high-strength steels and their applications.

关键词： Thermo-mechanicai treatment (TMT) Transformation-induced plasticity (TRIP) steel Mechanical properties Microstructure

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Synergistic effect of Al and Gd on enhancement of mechanical properties of magnesium alloys

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Progress in Natural Science:Materials International 2017年第3期27卷 228-235页

作者： Bita Pourbahari Masoud Emamy hamed mirzadeh School of Metallurgy and Materials Engineering College of EngineeringUniversity of Tehran

The effect of Gd/Al ratio on the properties of as-cast Mg-Gd-Al-Zn alloys was investigated by changing the chemical composition from that of AZ61 to GZ61. At the ratio of 1, the Al2Gd phase becomes predominant and Mg17Al12is hardly seen in the microstructure. As a potent inoculant, the Al2Gd phase resulted in intense grain refinement and enhancement of strength, ductility and toughness. For instance, the tensile strength and elongation to failure of Mg-3Gd-3Al-1Zn alloy were enhanced by4% and 180% compared with those of AZ61 alloy, respectively. However, at high Gd/Al ratios, the Al2Gd phase was replaced by（Mg,Al）3Gd and Mg5 Gd phases and very large grain sizes were achieved, which led to poor tensile properties and the appearance of cleavage facets on the fracture surfaces. Therefore, it can be deduced that the presence of Gd and Al, in appropriate amounts to reach Gd/Al ratio of ~ 1, is required for the achievement of grain refinement, good ductility, high strength, and the appearance of ductile fracture surfaces in the Mg-Gd-Al-Zn ***, the Mg-Gd-Al-Zn alloys can be considered as a new class of structural magnesium alloy and it is superior to both AZ（Mg-Al-Zn） and GZ（Mg-Gd-Zn） series of alloys.

关键词： Magnesium alloys Rare earth elements Microstructure Mechanical properties

A comparative study on the hot flow stress of Mg-Al-Zn magnesium alloys using a simple physically-based approach

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Journal of Magnesium and Alloys 2014年第3期2卷 225-229页

作者： hamed mirzadeh School of Metallurgy and Materials Engineering College of EngineeringUniversity of TehranP.O.Box 11155-4563TehranIran

A comparative study was carried out on the hot flow stress of AZ31,AZ61,and AZ91 magnesium *** hot working behaviors were studied through constitutive analysis based on a simple physically-based approach which accounts for the dependence of the Young's modulus and the self-diffusion coefficient of magnesium on *** the main difference between these alloys is the difference in their amount of aluminum,the differences in constitutive behavior were quantitatively characterized by relating the hot flow stress to amount of Al,which was not possible without the consideration of physically-based *** was concluded that the used approach in the current work can be considered as a versatile tool in future hot working and alloy development studies.

关键词： Mg-Al-Zn alloys Hot deformation Constitutive equations Activation energy Diffusion

基于物理的2024和7075铝合金简化热变形本构方程（英文）

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Transactions of Nonferrous Metals Society of China 2015年第5期25卷 1614-1618页

作者： hamed mirzadeh School of Metallurgy and Materials Engineering College of EngineeringUniversity of Tehran

通过基于物理方法的本构方程研究2024和7075铝合金的热变形行为。研究温度对铝弹性模量和自扩散系数的影响。研究结果表明,为描述峰值流变应力,铝的晶格自扩散激活能(142 kJ/mol)可作为Zener-Hollomon参数方程的变形激活能,而改进双曲... 详细信息

通过基于物理方法的本构方程研究2024和7075铝合金的热变形行为。研究温度对铝弹性模量和自扩散系数的影响。研究结果表明,为描述峰值流变应力,铝的晶格自扩散激活能(142 kJ/mol)可作为Zener-Hollomon参数方程的变形激活能,而改进双曲正弦函数中的理论指数可设为5。考虑基于物理的材料参数,可以对2024和7075铝合金的热流变应力进行对比研究。所采用的方法是一个通用工具,可用于热加工的对比研究和合金开发。

关键词：铝合金热变形本构方程激活能扩散

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17—4PH不锈钢组织变化研究有进展 008

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