Ti44Ni47Nb9合金热诱发马氏体相变的TEM研究

A TEM Study on Thermally-Induced Martensitic Transformation in Ti44Ni47Nb9 Alloy

采用Ｘ射线衍射及ＴＥＭ技术研究了Ｔｉ４４Ｎｉ４７Ｎｂ９形状记忆合金的相组成及热诱发马氏体相变。结果表明：该合金室温下由ＴｉＮＩ基体相和β－Ｎｂ相组成；当试样温度降低到Ｍｓ点以下时，具有Ｂ１９＇单斜结构的热诱发马氏体呈群团状区域式生长，形成由２－３个取向的孪晶微区组成的群团状马氏体；马氏体的亚结构主要为（１１１）ＭⅠ型孪晶，同时还有（００１）Ｍ孪晶和反相畴界。

The constitutional phases and thermally-induced martensitic transformation have been studied in the Ti44Ni47Nb9shape memory alloy by means of X-ray diffraction and TEM. The results show that the there exist two constitutional phases:TiNt matrix and β-Nb phase in the alloy, and the thermally-induced martensite with B19' monoclinic structure is growing in acluster form when the specimen is cooled below Ms temperature, thus forming the cluster-shaped martensite which generallyconsists of small twinning domains with two or three different orientations. Main substructures in marttnsite are (111)Mtype Itwins, (001)Mtwins and anti-phase boundaries.