Effects of structural heterogeneity on martensitic transformations of TiNi alloys  

作　　者：李君涛 郑雁军 崔立山 

机构地区：[1]Department of Materials Science and Engineering,China University of Petroleum

出　　处：《中国有色金属学会会刊：英文版》2007年第A02期1135-1139,共5页Transactions of Nonferrous Metals Society of China

基　　金：Project (50471021) supported by the National Natural Science Foundation of China;Project (20050425002) supported by Research Fund for Doctoral Program of Higher Education

摘　　要：By designing the shape of the original surface curve(sine-wave and square-wave),macroscopic domains with different dislocation density were introduced into the TiNi alloys and materials were endued with the characteristics of composites. Dilatometer(DL) and the differential scanning calorimeter(DSC) were used to study the properties of in-situ composites of TiNi alloys. The results show that the reverse transformation temperature range of in-situ TiNi composites with sine-wave surface is significantly enlarged. However,two endothermic peaks appear on DSC curves in the first heating process for these samples with square-wave surface. It is presumed that the interactions between the dislocation texture and martensite variants introduced when the TiNi martensite is cold rolled at room temperature might be responsible to the phenomena,which are compared with cold-rolled sheets with flat surface. All the phenomena above show it is feasible to control the thermal properties of a material by a proper design of the dislocation texture.By designing the shape of the original surface curve （sine-wave and square-wave）, macroscopic domains with different dislocation density were introduced into the TiNi alloys and materials were endued with the characteristics of composites. Dilatometer （DL） and the differential scanning calorimeter （DSC） were used to study the properties of in-situ composites of TiNi alloys. The results show that the reverse transformation temperature range of in-situ TiNi composites with sine-wave surface is significantly enlarged. However, two endothermic peaks appear on DSC curves in the first heating process for these samples with square-wave surface. It is presumed that the interactions between the dislocation texture and martensite variants introduced when the TiNi martensite is cold rolled at room temperature might be responsible to the phenomena, which are compared with cold-rolled sheets with flat surface. All the phenomena above show it is feasible to control the thermal properties of a material by a proper design of the dislocation texture.

关 键 词：形状记忆合金 钛镍合金 马氏体转变 冷变形 热膨胀 

分 类 号：TG139.6[一般工业技术—材料科学与工程]