WU Jianxin JIANG Bohong XU Zuyao(Hsu T.Y.) Shanghai Jiaotong University
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Shanghai
,
China [Originally published in ACTA METALL SIN(CHINESE EDN)25(3)1989 pp A173—A178. Professor
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Dept.of Materials Science
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Shanghai Jiaotong University
,
Shanghai
,
China
金属学报(英文版)
The influence of grain size and ordering degree of the parent phase on the shape memory re- covery in a Cu-25.62Zn-3.97Al-0.0018B(wt-%)memory alloy is investigated.A mathematical relationship is set up between the recovery ratio and ordering degree,probabili- ty of atoms at their ordered sites,grain size,the thickness of the grain boundary affected re- gions,the stress during deformation,as well as the critical shear stress.Shape memory effect reaches a maximum with varying grain size and increases linearly with increasing ordering parameter,which agrees well with experimental results.
关键词:
CuZnAl alloy
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null
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null
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null
李兵
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江伯鸿
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徐祖耀
金属学报
本文系统研究了Cu-Zn-Al形状记忆合金中形变度对形状回复的影响。从马氏体变态再取向的微观模型出发,阐明了预变形度ε对形状回复率η的影响规律及其本质。存在一个临界变形度ε_L(～2％),当ε<ε_L时,η随ε呈线性地增加(η=K_1ε-K_2d~(-1/2)),当ε>ε_L时,η随ε的增大而下降。同时讨论了拉伸变形与弯曲变形间的对应关系,得出弯曲变形时欲获最佳回复率的临界曲率半径R_L≈12mm。从热力学出发导出形状开始回复温度与变形度的关系T_s=A_s+(-1/2E_1ε~2+E_2ε)/ΔS_Tβ_1→M。所导出的定量规律,均与实验结果相吻合。
关键词:
形状记忆效应
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martensitic variant
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re-orientation
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CuZnAl alloy
程饴萱
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陈继勤
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方晓旻
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吕卫平
金属学报
本文研究了CuZnAl合金在马氏体及马氏体相变时的阻尼性能。结果表明,在马氏体状态的内耗是一种M/M界面内耗,利用位错内耗理论的表达式可解释其变化规律。在马氏体相变区的内耗,包括M/M界面内耗及相变内耗两级分,其中相变内耗又由马氏体逆转变产生的内耗及应力诱发马氏体内耗两部分组成,并且前者占主导地位、合金阻尼性能的衰减与激振过程中引入的位错有关,并在一定振动次数后趋向一稳定值。
关键词:
CuZnAl合金、马氏体
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CuZnAl alloy
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martensite
CHENG Yixuan CHEN Jiqin FANG Xiaomin L(?) Weiping Zhejiang University
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Hangzhou
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China
金属学报(英文版)
The internal friction of alloys in martensite state is believed to be an M/M interface one, which can be explained by an expression deduced from the theory of dislocation internal fric- tion.The internal friction during martensitic transformation consists of two parts,including those of the M/M interface and of the phase transformation.The latter is further composed of two portions,the major one produced by reverse martensitic transformation and the other from stress-induced martensite.It was also found that the degradation of damping properties of the CuZnAl alloys is related to the dislocation,which is introduced from the exciting pro- cess,and tends to be of stable value after certain excitements.
关键词:
damping property
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null
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null
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null
ZHAO Zengqi CHEN Feixia YANG Dazhi BAO Er ** Physical Laboratory
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Baotou Research Institute of Rare Earth
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Baotou
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014010
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China*** Dept.of Materials Engineering
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Dalian University of Technology
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Dalian
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116024
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China**** Dept.of Materials Engineering
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Yanshan Uni
材料科学技术（英文）
The present investigation showed that the re- laxation peak at about 200℃ (f≈1Hz) was related to bainitic transformation in a CuZnAl alloy.The peak decreased when bainite precipitated.The activation energy of the peak was the same as the apparent activation energy of bainitic transforma- tion.According to the relations between the peak and the bainitic transformation,the mechanism of the peak has been discussed.
关键词:
internal friction
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null
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null
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null
ZHU Min LI Guobin YANG Dazhi Dilian University of Technology
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Dalian
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China Dept.of Materials Engineering
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Dalian University of Technology
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Dalian 116024
,
China
金属学报(英文版)
The transmission electron microscopy has been used to investigate the fine structure variation of 18R martensite under deformation in a polycrvstalline CuZnAl shape memory alloys.It has been found that the strain is gabined by the reorientation of martensite variants in the ini- tial deformation stage.In addition to the result of optical microscopy studies,however,the reorientation is often incomplete and the interfaces among the prior variants still remain.A lot of twins will appear in martensite under enormous deformation,and the twin plane is(001) phane of martensite lattice.The dislocations has also been observed in some regions.In this case,the martensite will lose its thermoelasticitv and the shape memory effect will be damaged.
关键词:
fine structure
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null
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null
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null
Zengqi ZHAO Lab.of Physics
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Baotou Research Institute of Rare Earth
,
Baotou
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014010
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ChinaFeixia CHEN Dazhi YANG Dept.of Mater.Eng.
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Dalian University of Technology
,
Dalian
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116024
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ChinaEr BAO Dept.of Mater.Eng.
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Yanshan University
,
Qinhuangdao
,
066004
,
China
材料科学技术（英文）
Isothermal aging behaviours of a CuZnAl shape memory alloy have been investigated by means of dilatometry.The length of the specimens during isothermal aging from 190 to 280℃ increases with the aging time at each temperature.The isothermal aging kinetics fits in Avrami equation and the time exponent n decreases with the increase in aging temperature.The apparent activation energy for the isothermal aging process was measured to be 109.0kJ/mol,which is about equal to that of a relaxation internal friction peak at about 200℃ (f≈1 Hz) in the alloy.
关键词:
isothermal aging kinetics
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null
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null
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null
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null
QI Min ZHU Min ZHAO Xu YANG Dazhi ** Dept.of Materials Engineering
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Dalian University of Technology
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Dalian
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116023
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China*** Institute of Metals Research
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Academia Sinica
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Shenyang
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110015
,
China+ To whom correspondence should be addressed
材料科学技术（英文）
The influence of a small amount of α phase in β′ matrix on shape memory effect and superelasticity of CuZnAl shape memory alloy has been studied systematically.It has been found that transformation temperature can be adjusted in a large scale by controlling the amount of α phase, meanwhile,shape memory effect and superelasticity do not decrease obviously when there exists a small amount of α phase.Based on the optical and trans- mission electron microscopy observation,the influ- ence of α phase on shape memory effect and superelasticity has been discussed.
关键词:
αphase
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null
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null
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null
王红卫
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吴望子
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王凤庭
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杨大智
金属学报
对Cu基形状记忆合金CuZnAl进行了干滑动磨损,采用扫描电镜观察磨损表面及磨屑.结果表明,CuZnAl合金的磨损过程受塑性变形控制,粘着与转移磨损和剥离磨损是材料失重的两种主要机制.电镜薄膜拉伸时显微裂纹尖端发生了应力诱发马氏体相变.用显微裂纹钝化作用的马氏体择优取向机制和应力诱发马氏体相变机制阐述了这种软基体高变形能力材料的耐磨本质。
关键词:
铜基形状记忆合金
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shape memory alloy
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wear
