马氏体相变理论研究的最新进展

马氏体相变的切变机制存在误区,研究马氏体相变的形核、长大、组织形貌及亚结构等具有重要理论价值和实际意义。本文综合整理了近年来马氏体相变试验研究的新成果,指出马氏体在晶界、相界面、位错等缺陷处形核,并非切变形核;发现板条状马氏体中存在层错亚结构。位错、孪晶亚结构的形成也非切变所致;马氏体组织形貌的演化与应变能有密切关系;马氏体表面浮凸是相变比体积增大所致,N型切变缺乏试验依据。

Latest Advance in Study on Martensite Phase Transformation

It is of great significance theoretically and practically to restudy the nucleation, growth, microstructure and substructure during martensite phase transformation because there are misunderstandings about the shear mechanism of martensite phase transformation. The new study results of martensite phase transformation in recent years are summarized in this paper. The key points are as follows： Martensite can nucleate along the austenite crystal grain boundary, at the interface and at the defects such as dislocations, which is not shear transformation. Stacking faults are found in lath martensite and the substructure of dislo- cation and twin crystal is not caused by shear transformation. The morphology evolution of martensite is the result of the volumetric strain energy of transformation, which has nothing to do with shear transformation. The surface relief of martensite results from the bulk expansion during martensite phase transformation and the N-shaped shear lacks of test evidence.