马氏体相变切变机制的现代试验验证和切变能的计算——再评“马氏体相变的非切变机制”  

Modern experimental verifications of shear mechanism of martensitic transformation and calculation of shear energy——Comment on "non-shear mechanism of martensitic transformation" again

作　　者：张骥华[1] 戎咏华[1] 

机构地区：[1]上海交通大学材料科学与工程学院,上海200240

出　　处：《金属热处理》2013年第5期40-47,共8页Heat Treatment of Metals

摘　　要：遴选了马氏体相变切变机制的现代试验结果,证明马氏体相变切变机制的正确性。在诸多有色合金中马氏体相变产生的切变能相对相变驱动力而言较大,但母相弹性常数的测定表明,马氏体相变时母相的弹性常数在特定方向将产生软化(对应切变方向),由此可有效地降低马氏体相变的切变能,从而得以使马氏体相变以切变形核。透射电镜的观察表明,层错迹线被单变体马氏体切过后将变成折线,并且试验测定的切变角与理论切变角很好地符合。透射电镜高分辨像揭示了马氏体/奥氏体界面处存在过渡区。这些区域的原子约从fcc奥氏体(111)面上的位置切变位移了50%,这是不同于扩散型相变的贝氏体/奥氏体界面。随后介绍了徐祖耀计算Fe-C合金马氏体相变切变能的方法。最后,指出了"马氏体相变非切变机制"理论提出者刘宗昌等由于对前人工作缺乏深入了解,在错误的物理概念基础上来计算马氏体相变切变能,导致错误结论。Several modern experiments were selected to prove the correctness of shear mechanism of martensitic transformation. In a lot of non-ferrous alloys the shear energy is large compared with driving force of martensitic transformation, however, the measurements of elastic constants indicate that the elastic constants of parent phase will soften along special direction （ which corresponds to shear direction ）, and this effect will effectively lower the shear energy of martensitie transformation accompanying shear nucleation. The observation of transmission electron microscope （TEM） indicates that the straight trace of a stacking fault will change to terraced when the stacking fault will be sheared by a single variant of martensite, moreover, the shear angle measured is well consistent with the shear angle calculated. High resolution TEM image reveals that there are a transition region near the interface between martensite and anstenite, and atoms in the region are at the position shifted by 50% from the original （111）of fee austenite, which is different from the interface between bainite and austenite produced by diffusing transformation. The calculation method of shear energy for Fe-C alloys proposed by Hsu T Y（ Xu Zuyao） was introduced, and the ＂non-shear mechanism of martensitie transformation＂ proposed by Liu Zongehang was also commented. It is pointed out that the incorrect calculation of shear energy by liu is attributed to the improper physical concept and lack of deep understand of the previous researches, which results in the error conclusion of ＂non-shear mechanism of martensitic transformation＂.

关 键 词：马氏体相变 切变机制 弹性软化 切变角 透射电镜 

分 类 号：TG111.5[金属学及工艺—物理冶金]