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本文利用EBSD技术研究了高锰钢压缩形变过程中γ→ε→α'马氏体相变的晶体学特点, 分析了奥氏体孪生与奥氏体晶粒取向对相变的影响. 结果表明, 由于α'马氏体在2个ε变体的交叉处形成, 而ε相变区域普遍存在奥氏体形变孪晶并且ε可在孪晶界上形成, 因此孪生对相变起着重要的作用; 而孪生的难易受奥氏体取向的影响. 分析认为, 低指数的{100}, {111}和{110}奥氏体内因多变体同时孪生而比高指数取向容易促进ε变体间的交叉从而促进α'的形成; 形变使ε变体数目或新取向增多, 但小尺寸的ε难以促进$\alpha'$的形成.

The excellent combination of strength and elongation and the super work hardening behavior of high manganese TRIP/TWIP (transformation–induced plasticity/twinning–induced plasticity) steels are due to the presence of two kinds of martensitic transformations and their complicated interactions of three phases during deformation. This work investigated the crystallographic characteristics of γ →ε →α' transformation, and in particular, the effects of deformation twins and austenitic grain orientations on martensitic transformation by means of EBSD technique. Results showed that α'–martensite was triggered at the intersection of two ε-martensite variants. Deformation twins were frequently detected near ε–martensite, thus twins promoted the formation of ε–martensite and played n important role during TRIP pocess. However, twinning was affected by austenite grain orientations. It is suggested that austenitic grain orientations with low indices, such as {100}, {111} and {110}, more easily promoted the intersection of ε–variants due to the multi–twinning and thus facilitated further α′–martensite formation than those with high indices. Deformation increased the number of " variants but reduced their sizes and therefore it is difficult for the small strain–induced ε–martensites to transform into α′–martensites smoothly.