崔玉亭
,
王万录
,
廖克俊
材料研究学报
通过对磁感生应变和磁增强相变应变的测量, 研究了Ni50.5Mn26.5Ga23单晶磁感生应变的温度依赖性和磁控形状记忆效应. 结果表明, 随着温度的降低; Ni50.5Mn26.5Ga23单晶的饱和磁感生应变量先是迅速减小, 然后缓慢减小; 磁场的方向不同, 随着温度降低饱和磁感生应变量减小的速度也不
同. 根据合金形状记忆的特点和马氏体变体择优取向的机理, 对实验结果进行了分析和讨论.
关键词:
金属材料
,
temperature dependence
,
strain
,
shape memory effect
漆璇
,
江伯鸿
,
徐祖耀
金属学报
研究了Cu-Zn-Al合金分别经水淬、分级淬火和淬火加时效处理后,马氏体的有序化程度及其和形状记忆效应(SME)之间的关系.有序化程度用一些特定马氏体线对的面间距差值△d来表征,线对指数应满足下式:(h_1~2-h_2~2)/3=(k_2~2-k_1~2)/n(对9R马氏体n=1,对18R马氏体N=4).分级淬火得到M18R马氏体,其△d值随分级等温时间而增大,与形状恢复能力η的提高一致.水淬得到M9R马氏体,刚淬火状态有相当大的△d和良好的SME,但室温停留使△d和η均下降,TEM点阵条纹象证实这是淬火过饱和空位在(001)_M基面聚集、降低有序程度的结果.淬火后高温时效(180℃)或过高的分级温度都会使△d和η下降,这与α相析出以及可能发生的溶质原子偏聚有关,都会降低有序程度.
关键词:
Cu-Zn-Al合金
,
martensite
,
ordering
,
shape memory effect
LI Yongsen JIN Yongbai YU Ronghai Institute of Metal research
,
Academia Sinica
,
Shenyang
,
China Associate Professor
,
Institute of Metal Research
,
Academia Sinica
,
Shenyang 110015
,
China
金属学报(英文版)
Based on experimental study of the time dependence of the recoverable shape memory effect (SME)of shape memory alloys Ti50Ni50,Ti50Ni48Cu2 and Ti50Ni45Cu5 an empirical re- lationship between recoverable strain energy,U_r,and temperature,T.was derived as: U_r=U_o[1-exp(-mT_R~n)] where m—characteristic constant related to material,and n-shape-temperature sensitivity. The Johnson-Mehl-Aerami's phenomenological description of the time dependence of phase transformation was adopted to obtain a semiquantitative relationship associated with recoverable SME.between thermoelastic martensite transformation and temperature.This semiquantitative relationship is correspondent with the empirical expression.
关键词:
shape memory effect
,
null
,
null
,
null
WU Jianxin JIANG Bohong XU Zuyao(Hsu T.Y.) Shanghai Jiaotong University
,
Shanghai
,
China [Originally published in ACTA METALL SIN(CHINESE EDN)25(3)1989 pp A173—A178. Professor
,
Dept.of Materials Science
,
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
,
null
,
null
,
null
QI Xuan JIANG Bohong XU Zuyao(T.Y.HSU) Shanghai Jiaotong University
,
Shanghai.China Qi Xuan
,
Dept.Marter.Sci.and Eng.
,
Shanghai Jiaotong University
,
Shanghai
,
China
金属学报(英文版)
The correlation between the shape memory effect(SME)and the ordering degree in martensite formed through various heat-treatment processes,e.g.ice water quenching, step-quenching and aging etc.,has been studied in a Cu-26Zn-4Al alloy.The martensite or- dering degree is estimated by △d,the spacing difference of some pairs of diffracting planes with indices satisfying a relation of(h_1~2-h_2~2)/3=(k_2~2-k_1~2)/n(n=1 for 9R martensite,n=4 for 18R martensite).M 18R martensite is obtained from step-quenching,in which the value of △d increases with the holding duration of step-quenching,and the shape recovery rate η increases synchronouslly.9R martensite is obtained from direct water-quenching,the value of △d is quite large and SME is also good at just quenching state.But both △d and η decrease continuously with aging time at room temperature.This stabilization phe- nomenon of martensite is explained by the observation of TEM lattice fringe image,and it may be attributed to the clustering of quenched-in supersaturated vacancies at (001)_M close-packed plane in martensite and decreasing the ordering degree.A reduction in △d and η occuring in the specimens on step-quenching or aging at higher temperature, which may be related to the precipitation of the α-phase and the enrichment of solute atoms, decreases the ordering degree.
关键词:
Cu-Zn-Al alloy
,
null
,
null
,
null
,
null
LI Yan WU Yigui Luoyang Institute of Technology
,
Luoyang
,
ChinaHASHIMOTO Hatsujiro Okayama University of Science
,
Japan
金属学报(英文版)
The reversible transformation between matrix and martensite in Ni-Ti shape memory alloys has been dynamically observed under TEM.The orientation relation between martensite and austenite as well as the structural change near the transition temperature has been also studied with the help of HREM SADP.The results show that the orientation relation between martensite and austenite is[11]_A//[10]_M,[110]_A//[001]_M,(110)_A//(001)_M and the angle between(110)_A and(010)_M is about 6.5°.The crystal defects of martensite are found to be twin and stacking fault,and the twin plane as(100).
关键词:
Ni-Ti alloy
,
null
,
null
王佩红
,
章文
,
田中克彦
,
戴旭涵
,
赵小林
功能材料
提出了一种新的方法可以使锆钛酸铅压电陶瓷PZT7具有形状记忆效应.用自制的sawyer-Tower电路测试得到PZT7方形样品发生极化反转对应的电场强度大约为130kV/cm.当施加对称的饱和极化电压370V时,PZT7/Si(109/146μm)悬臂梁端部的变形一电场曲线呈现典型的"蝴蝶"形状.在外电场为0时,悬臂梁端部的变形为0.如果施加不对称的极化电压,悬臂梁端部的变形--电场曲线发生明显的变化.不同的反向极化电压使悬臂梁端部产生不同的变形,而且,电压和变形是一一对应的.因此,在外电场为零时,PZT7/Si悬臂梁可以具有多个不同的稳定位置,表现出明显的形状记忆效应.实验表明,对于长度为15.5mm的PZT7/Si悬臂梁而言,当施加的反向极化电压从120V回到0时,悬臂梁端部产生的变形最大,为68.5μm.
关键词:
压电陶瓷
,
PZT7
,
形状记忆效应
,
悬臂梁
,
极化电压
