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Journal of Materials Science & Technology 2018年第11期34卷 2042-2050页

作者： Wenke Wang Wenzhen Chen Wencong Zhang Guorong Cui Erde Wang School of Materials Science and Engineering Harbin Institute of Technology

The rolling direction（RD） and the transverse direction（TD） samples were obtained from an as-rolled ZK60 magnesium alloy sheet with strong anisotropy of initial texture and their mechanical properties were tested at various deformation temperatures. Meanwhile, the microstructure and texture of these samples after fracture were investigated. Results revealed that a higher flow stress along the RD than that along the TD at room temperature were ascribed to the strong anisotropy of transitional texture, and this texture effect was remarkably weakened with the increase of deformation temperature. deformation structure was dominant at 100℃, and was replaced by dynamic recrystallization structure when the deformation temperature increased to 200℃ and 300℃. The texture presented a strong texture（transitional texture in the RD sample and basal texture in the TD sample） at 100℃, but its intensity visibly decreased and texture components became more disperse at 200℃ and 300℃. These microstructure and texture results were employed in conjunction with calculated results to argue that raising deformation temperature could increase the activity of non-basal slip by tailoring the relative critical resolved shear stress of each deformation mode and finally result in low texture effect on mechanical anisotropy.

关键词： ZK60 magnesium alloy deformation temperature Texture anisotropy Dynamic recrystallization Non-basal slip

Effect of deformation temperature on the hot compressive behavior of metal matrix composites with misaligned whiskers

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Rare Metals 2007年第2期26卷 182-192页

作者： LI Aibin MENG Qingyuan GENG Lin DENG Chunfeng YAN Yiwu School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China Department of Astronautical Engineering and Mechanics Harbin Institute of Technology Harbin 150001 China

A multi-inclusion cell model is used to investigate the effect of deformation temperature and whisker rotation on the hot compressive behavior of metal matrix composites with misaligned whiskers. Numerical results show that deformation temperature influences the work-hardening behavior of the matrix and the rotation behavior of the whiskers. With increasing temperature, the work hardening rate of the matrix decreases, but the whisker rotation angle increases. Both whisker rotation and the increase of deformation temperature can induce reductions in the load supported by whisker and the load transferred from matrix to whisker. Additionally, it is found that during large strain deformation at higher temperatures, the enhancing of deformation temperature can reduce the effect of whisker rotation. Meanwhile, the stress-strain behavior of the composite is rather sensitive to deformation temperature. At a relatively lower temperature （150℃）, the composite exhibits work hardening due to the matrix work hardening, but at relatively higher temperatures （300℃ and above）, the composite shows strain softening due to whisker rotation. It is also found that during hot compression at higher temperatures, the softening rate of the composite decreases with increasing temperature. The predicted stress-strain behavior of the composite is approximately in agreement with the experimental results.

关键词： metal matrix composite hot compressive behavior deformation temperature finite element method

Transformation of low carbon steel during deformation at γ/α temperature based on online rolling data

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Baosteel Technical Research 2012年第4期6卷 51-54页

作者： WANG Jintao ZHANG Suoquan SUN Yezhong HE Xiaoming JIAO Sihai Hot Rolling Plant Baoshan Iron & Steel Co. Ltd. Metallurgical Process Division Research Institute Baoshan Iron & Steel Co. Ltd.

Alloying elements, such as silicon and manganese, have a major impact on the phase transformation point of steel. Specifically, manganese is an element for the expansion and stability of the austenite region, while silicon can expand and stabilize the ferrite region. Phase transformation occurs during the hot rolling process for the steel with certain silicon content, which leads to great changes of the deformation resistance, thereby affecting the rolling stability. Consequently, a better understanding of phase transformation in the rolling process will contribute to the enhancement of product quality. In this paper ,the on-line rolling data were processed by means of the inverse calculation method. In this method, the steel deformation resistance with various silicon and manganese contents was obtained and analyzed to determine the deformation behavior of the steel, which can help improve the on-line control model and enhance the steel quality.

关键词： phase transformation hot rolling deformation temperature rolling data deformation resistance

Research on elevated temperature deformation behavior of Ti-6Al-4V sheets

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Rare Metals 2009年第6期28卷 550-553页

作者： SUN Shengdi GUO Bin SHAN Debin ZHONG Yingying School of Materials Science ＆ Engineering Harbin Institute of Technology Harbin 150001 China

Hot deformation behaviors were studied by means of scanning electron microscopy （SEM） and uniaxial thermal tension. The effect of deformation temperature and strain rate on flow stress was evaluated, and deformation mechanism was analyzed. The results show that the stress-strain curves of Ti-6Al-4V （TC4） alloy sheet and TC4 alloy bar at elevated temperatures have different forms and rules. Flow stress of TC4 is controlled by both strain rate and deformation temperature. The flow stress decreases with the increase of high temperature. deformation mechanisms exhibit dynamic recovery and recrystallization feature within high temperature region and grain boundary slip behaviors at low temperature.

关键词： titanium alloys hot tension strain rate deformation temperature

Hot deformation Behavior of V-Microalloyed Steel

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Journal of Iron and Steel Research International 2010年第8期17卷 55-60页

作者： REN An-chao JI Yu ZHOU Gui-feng YUAN Ze-xi HAN Bin LI Yi Institute of Material Science and Metallurgy Wuhan University of Science and Technology Wuhan 430081 Hubei China Research and Development Center Wuhan Iron and Steel (Group) Co Wuhan 430080 Hubei China International Trade Company Wuhan Iron and Steel (Group) Co Wuhan 430080 Hubei China

Through the expansion curve of continuous cooling transformation at different cooling rates measured by THERMECMASTOR-Z thermal simulator for U75V rail steel,the continuous cooling transformation curve was *** influence on steel microstructure and hardness at different cooling rates was *** softening behavior of isothermal deforming in austenite area of 850-1000 ℃ in the interval of passes was also studied by double-pass compression *** results show that the product of austenite transformation is pearlite when the cooling rate is lower than 10 ℃.When the cooling rate was in the range of 10-50 ℃·s-1,only martensite was *** hardness of the test steel increases with increasing the cooling *** the condition of deformation of 30% and deformation rate of 3 s-1,the relaxation time for complete recrystallization was shorter than 100 s when deformation temperature was higher than 1000 ℃.When deformation temperature was lower than 880 ℃,complete recrystallization of steel was difficult to achieve even if the relaxation time is extended.

关键词： U75V rail steel thermal simulation continuous cooling transformation curve deformation temperature static recrystallization

Effects of deformation Conditions on Dynamic Recrystallization of a Nb Microalloyed Anti-seismic Rebar

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Journal of Donghua University(English Edition) 2015年第5期32卷 879-886页

作者：黄敏曹建春陈伟周晓龙杨银辉钟仲华 College of Material Science and Engnieering Kunming University of Science and Technology College of Metallurgical and Energy Engineering Kunming University of Science and Technology WISCO Kumming Iron & Steel Co . Ltd.

The hot deformation behavior of a Nb microalloyed anti-seismic rebar was investigated at deformation temperatures of 950-1 100 ℃ and strain rates of 0. 01-0. 1 s- 1 on a Gleeble-3800 thermo-mechnical simulator. The flow stress-strain curves show the typical dynamic recrystallization with a peak,before reaching the steady state flow at higher deformation temperatures and lower strain rates. The constitutive equation governing the dynamic recrystallization( DRX) was obtained and the average activation energy of deformation was calculated as Q = 389. 5 kJ / mol by the regression analysis. The DRX grain size was also found to decrease with the increasing strain rate and the decreasing deformation temperature. The austenite grain size was refined from 118. 0 μm to 15. 07-40. 01 μm by DRX. The DRX grain size under diverse deformation conditions predicted by mathematical model agrees well with experimental results.

关键词： dynamic recrystallization(DRX) deformation temperature strain rate Nb microalloyed rebar

Formation mechanism of hierarchical twins in the CoCrNi medium entropy alloy

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Journal of Materials Science & Technology 2023年第9期140卷 19-32页

作者： Dongpeng Hua Xiaorong Liu Wan Wang Qing Zhou Qiaosheng Xia Shuo Li Junqin Shi Haifeng Wang State Key Laboratory of Solidification Processing Center of Advanced Lubrication and Seal MaterialsNorthwestern Polytechnical UniversityXi’anShaanxi 710072PR China Queen Mary University of London Engineering School Northwestern Polytechnical UniversityXi’anShaanxi 710072PR China

The three-dimensional hierarchical twin network has been proved to be the source of the excellent strength-ductility combination in the CoCrNi medium entropy *** the formation mechanism of hierarchical twins,however,remains a challenge using either the post-mortem or the in-situ microstructural *** this study,the atomistic formation mechanism of hierarchical twins was investigated using molecular dynamics simulations,with special focus on the effects of strain rate and deformation *** to the primary twin boundaries kink-driven hierarchical twinning tendency in pure FCC metals,the chemical inhomogeneity in CoCrNi can reduce the necessary kink height to trigger conjugate twins(CTWs),fascinating the formation of twin *** room temperature,the plastic deformation is dominated by primary twins(PTWs)and conjugate slips at a relatively lower strain rate(e.g.,5×10^(7)s^(−1)).The hierarchical twins can be activated in cases of deforming at a higher strain rate(e.g.,2×10^(8)s^(−1)).Further increasing the strain rate(e.g.,1×10^(10) s^(−1))leads to the phase-transformation induced *** cryogenic temperatures,the hierarchical twins are promoted within a large range of strain rates(e.g.,5×10^(7)–1×10^(10) s^(−1)).A higher temperature leads to the synergy of CTWs and primary slips at a lower strain rate,but hierarchical twins at a higher strain *** this basis,a qualitative comparison and scalable trends between experiments and simulations were *** present study would not only provide the basic understanding for the twinning behavior found experimentally,but also contribute to the design of medium/high entropy alloys with excellent mechanical performances by tuning microstructures.

关键词： Hierarchical twin Medium entropy alloy Strain rate deformation temperature Molecular dynamics simulation

Structure and properties of AZ31B magnesium alloy sheets processed by repeatedly unidirectional bending at different temperatures

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Transactions of Nonferrous Metals Society of China 2010年第10期20卷 1815-1821页

作者：黄光胜宋波徐伟张雷 National Engineering Research Center for Magnesium Alloys Chongqing University College of Materials Science and Engineering Chongqing University CISDI Engineering Company Limited

Repeatedly unidirectional bending(RUB) was applied to the magnesium alloy sheet to improve the basal *** effect of RUB temperature on resulting structure and room temperature properties was *** texture components of the sheet undergoing RUB at recovery temperature were similar to those of the sheet undergoing RUB at room temperature(RT).As the RUB temperature increased to above recrystallization temperature,the texture components became more disperse and the pyramidal components *** the increase of RUB temperature,the grain size near the surface of the sheets undergoing RUB tended to grow *** the sheets were processed by RUB at medium-high temperature followed by annealing at 533 K,the yield strength and fracture elongation were lower than those of the cold rolled sheet;however,the Erichsen value was slightly higher than that of the cold rolled *** sheet undergoing RUB at RT followed by annealing at 533 K represented the best mechanical properties.

关键词： magnesium alloy sheets repeatedly unidirectional bending deformation temperature texture

Simulation-Based Investigation of Crack Formation in Forged MB15 Magnesium Alloy

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Journal of Electronic Research and Application 2024年第1期8卷 73-79页

作者： Lulu Song Dongmei Liu Jie Yuan Ruihuan Tian Liying Jin Metrological Physics and Chemistry Center AVIC Aerospace Life-Support IndustriesLtd.Xiangyang 441003Hubei ProvinceChina Xiangyang Key Laboratory of Intelligent Manufacturing and Machine Vision Hubei University of Arts and ScienceXiangyang 441053Hubei ProvinceChina

In the process of riveting an MB15 forging die,cracks were discovered emerging along the longitudinal direction and near the riveting *** fracture analysis,microscopic observation,energy spectrum analysis,metallographic examination,and hardness test,the properties and causes of the cracks are *** results indicate that the cracking type is intergranular brittle cracking,occurring during the forging ***,the recrystallization at the crack site is found to be incomplete,which is attributed to the low deformation temperature.

关键词： MB15 Forging die Crack deformation temperature

Enhanced magnetic properties in Nd-Fe-B magnets prepared by spark plasma sintering via die-upsetting process

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Journal of Rare Earths 2011年第7期29卷 660-663页

作者：胡志华储林华李军刘颖 Department of Materials Engineering Hubei University of Automotive Technology College of Materials Science and Engineering Sichuan University

The magnetic properties and microstructure of Nd-Fe-B magnets prepared by spark plasma sintering with different die-upsetting processes were investigated. The results showed that the optimum magnetic properties of die-upset Nd-Fe-B magnets were obtained at 680 ℃ when the die-upset level was 60%, and the degree of magnetic alignment was 0.84. The microstructures showed that the coarse grains oc-curred predominantly within certain areas, and abnormal grain growth was not observed within the major areas of well-aligned grains. There existed many small spherical grains, which stacked together and were not aligned during die upsetting when the deformation temperature was 650 ℃. These small spherical grains grew up, and were aligned when the deformation temperature increased from 650 to 680 ℃, which could improve the crystallographic alignment of die-upset Nd-Fe-B magnets.

关键词： Nd-Fe-B magnets magnetic properties the die-upset level deformation temperature spark plasma sintering rare earths