检索结果-南通市图书馆

Journal of Magnesium and Alloys 2023年第8期11卷 2891-2900页

作者： Yiping WU Yuzhen JIA Sha Zhang Yu Liu Hanqing Xiong Gang Chen Department of Mechanical and Electrical Engineering Changsha UniversityChangsha 410003China Bichamp Cutting Technology(Hunan)Co. LtdChangsha 410200China College of Material Science and Engineering Hunan UniversityChangsha Hunan 410082China

flow softening behavior of a homogenized Mg-7Gd-4Y-1Nd-0.5Zr alloy under compression to a final strain of∼1.8 at elevated temperatures of 450∼550℃ and a constant strain rate of 2s^(−1) has been investigated by optical microscopy,scanning electron microscopy,electron back-scattered diffraction and transmission electron *** results show that true stress first rises to the peak point and then drops to the bottom value and increases again with further increasing strain at each *** dynamic recrystallization(DRX)and continuous DRX contribute to the formation of new fine grains at temperatures 450∼475℃ when the restoration is caused by both DRX and texture change due to extension twinning,resulting in the larger softening degrees compared with the softening effects owing to continuous DRX and discontinuous DRX at 500∼550℃ when twinning activation is suppressed.500℃ is the transition temperature denoting a significant decline in the contribution of twinning and TDRX to the strain with increasing *** cuboid-shape phase exists in both homogenized and compressed samples,while the compositions are varied.

关键词： Mg-Gd-Y alloy Elevated temperature compression flow softening Dynamic recrystallization

flow softening behavior and microstructure evolution of Al-5Zn-2Mg aluminum alloy during dynamic recovery

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2014年第1期24卷 42-48页

作者：李落星王冠刘杰姚再起湖南大学汽车车身先进设计制造国家重点实验室长沙410082 湖南大学机械与运载工程学院长沙410082 浙江吉利汽车研究院有限公司杭州311228

The flow stress behavior and microstructure development of Al-5Zn-2Mg （7005） aluminum alloy were studied by hot compression tests at deformation temperatures between 300-500 ＆#176;C and strain rates between 0.05-50 s-1. The deformed structures of the samples were observed by optical microscopy （OM）, transmission electron microscopy （TEM） and electron backscattering diffraction （EBSD） analysis. The calculated activation energy is 147 kJ/mol, which is very close to the activation energy for lattice self-diffusion in aluminum （142 kJ/mol）. Dynamic recovery is the dominant restoration mechanism during the deformation. At high strain rate of 50 s-1, temperature rise due to deformation heating leads to a significant flow softening. Microstructure observations indicated that the remaining softening after deformation heating correction at high strain rate and the softening observed at high temperature are associated with grain coarsening induced by grain boundary migration during dynamic recovery process.

关键词： 7005 aluminum alloy deformation dynamic recovery flow softening microstructure evolution

Dynamic softening and microstructural evolution during hot deformation of Al-Cu-Mg-Zr alloys with different homogenization cooling rates

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2021年第3期40卷 626-634页

作者： Guo-Wei Bo Guan Wang Fu-Lin Jiang Can Liu Rong Chen Hui Zhang College of Materials Science and Engineering Hunan UniversityChangsha410082China School of Mechanical Engineering Ningxia UniversityYinchuan 750021China

An Al-Cu-Mg-Zr alloy,which obtained different homogenization cooling rates by changing the heattreated sample size,was compressed to various strains at the deformation temperature of 300℃ and strain rate of 0.01 s^(-1).The results showed that the homogenization cooling rate had strong effects on the hot deformation behavior of the *** flow stress and relative dynamic softening rate of the alloy were significantly higher under a high cooling rate(HCR) than those under a low cooling rate(LCR).Furthermore,based on X-ray diffraction,scanning electron microscopy,transmission electron microscopy,and thermodynamic equilibrium phase calculation,the substructure evolution in the grain interior,morphology,and spatial distribution of the precipitates were studied to determine the differences in the flow softening *** main softening mechanism could be summarized as dynamic recovery and precipitation coarsening for the LCR alloy and dynamic precipitation for the HCR alloy.

关键词： Al-Cu-Mg-Zr alloy Homogenization Hot compression flow softening Dynamic precipitation

Deformation behavior and microstructural evolution of Al-Zn-Cu-Mg-Sc-Zr alloy during high temperature compression

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2009年第4期16卷 530-534页

作者：李文斌潘清林刘俊生梁文杰何运斌刘晓艳 School of Materials Science and Engineering Central South University Department of Civil Engineering Hunan City University

The deformation behavior of a new Al-Zn-Cu-Mg-Sc-Zr alloy was investigated with compression tests in temperature range of 380?470 ℃ and strain rate range of 0.001-10 s-1 using Gleeble 1500 system, and the associated microstructural evolutions were studied by metallographic microscopy and transmission electron microscopy. The results show that true stress—strain curves exhibit a peak stress, followed by a dynamic flow softening at low strains (εflow softening is attributed mainly to dynamic recovery and dynamic recrystallization.

关键词： Al-Zn-Cu-Mg-Sc-Zr alloy hot deformation flow softening microstructural evolution activation energy

Characterization of dynamic microstructure evolution during hot deformation of Al-4.10Cu-1.42Mg-0.57Mn-0.12Zr alloy

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2014年第11期24卷 3477-3485页

作者：刘灿张辉蒋福林湖南大学材料科学与工程学院长沙410082 湖南大学湖南省喷射沉积技术及应用重点实验室长沙410082 Department of Materials Science and Engineering Mc Master University Hamiltion Ontario L8S 4L7 Canada

The Al?4.10Cu?1.42Mg?0.57Mn?0.12Zr alloy was compressed to different strains at deformation temperature of 300 oC and strain rate of 10 s?1 on Gleeble?1500 system. The dynamic complex microstructures evolutions were investigated by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The true stress?true strain curves exhibited a peak stress at critical strain, after which the flow stresses decreased monotonically, showing a dynamic flow softening. As the strain increased, the dislocation tangled to cell structure and sub-grain structure, which indicated the occurrence of dynamic recovery during deformation. Dynamic precipitations ofS (Al2CuMg),θ (Al2Cu) and Al3Zr phase were accelerated and coarsened by deformation. ContinuousS phases precipitated in the Al matrix and discontinuousS phases were found to be nucleated near the Al3Zr phase and at the sub-grain boundary. The flow softening mechanism was resulted from the reduction of dislocation density which attributed to dynamic recovery and precipitates coarsening.

关键词： aluminum alloy hot deformation flow softening dynamic recovery dynamic precipitation