Co-Ni磁控形状记忆合金的相变及显微结构  

Phase transformation and microstructure of Co-Ni Magneto-shape memory alloys

作　　者：刘岩[1] 江伯鸿[1] 周伟敏[1] 漆璿[1] 

机构地区：[1]上海交通大学国家教育部高温材料及高温测试重点实验室,上海200030

出　　处：《功能材料》2002年第1期49-51,共3页Journal of Functional Materials

基　　金：国家自然科学基金资助项目(59771029)

摘　　要：Ｃｏ基合金中存在从ｆｃｃ到ｈｃｐ的马氏体相变，其奥氏体－马氏体界面完全共格，层错能较低，马氏体相变的驱动力很小，易通过外磁场诱发ａ／６〈１１２〉Ｓｈｏｃｋｌｅｙ不全位错的移动引起相变而产生对外的应变输出，是一种理想的磁控形状记忆候选材料。本文研究了Ｃｏ－Ｎｉ合金的金相组织和透射电子显微结构，测定了一组Ｃｏ－Ｎｉ合金的马氏体相变及其逆转变温度。研究表明：Ｃｏ－Ｎｉ合金的马氏体组织呈有规则的条片状，马氏体相变温度随Ｎｉ含量的增加而降低，其母相中存在层错，母相的饱和磁化强度高达１２４Ａｍ２·ｋｇ－１，是典型磁控形状记忆材料Ｎｉ２ＭｎＧａ的近两倍。Co-based alloys exhibited from fcc to hcp martensitic transformation and the martensite-austenite interfaces were perfectly coherent. Since the stacking fault energy and driving force of martensitic transformation in Co-based alloys are quite low, the a/6 (112) Shockley partial dislocations were very easy to move if induced by applied magnetic fields. This motion causes the magnetic-field-induced strains, which imply that Co-based alloys are kinds of potential magneto-shape memory materials. In Co-Ni alloys, regular plate-shaped martensitics were observed by optical microscope and many stacking faults were found by transmission electron microscope (TEM). The Co-Ni alloys exhibit high saturation magnetization of 124Am2 &middot kg-1, which is almost twice as high as that of Ni2MnGa, a typical magneto-shape memory material. It is also found that the martensitic transformation temperatures (Ms) of Co-Ni alloys decrease gradually with the increase of Ni wt%.

关 键 词：Co-Ni合金 磁控形状记忆效应 不全位错 层错 马氏体相变 显微结构 形状记忆合金 

分 类 号：TG139.6[一般工业技术—材料科学与工程]