Mapping the parent austenite orientation reconstructed from the orientation of martensite by EBSD and its application to ausformed martensite
Mapping the parent austenite orientation reconstructed from the orientation of martensite by EBSD and its application to ausformed martensite
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DOI：
10.1016/j.actamat.2010.08.001
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发表时间：
2010-11-01
期刊：
影响因子：
9.4
通讯作者：
Furuhara, Tadashi
中科院分区：
文献类型：
--
作者：
Miyamoto, Goro;Iwata, Naomichi;Furuhara, Tadashi
基于电子背散射衍射测量的板条马氏体取向，提出了一种重建母体奥氏体局部取向的新方法。假设马氏体与母奥氏体之间存在特定取向关系（OR），当实验数据与预测马氏体取向之间的差异最小时，通过最小二乘拟合得到奥氏体的局部取向。首先，精确测定了奥氏体与板条马氏体之间的平均比值，发现在低碳马氏体中，马氏体与母体奥氏体之间的紧密堆积面和方向都偏离了1度以上。重建的奥氏体取向图的质量很大程度上取决于用于计算的OR。当使用Kurdjumov Sachs （K-S）或Nishiyama-Wasserman (N-W) ORs时，由于K-S或N-W ORs中（0 1 1）（α）堆叠的镜像对称性，奥氏体取向经常被误认为是孪生取向。相比之下，通过使用测量的OR，在紧密排列的平面和方向不平行的情况下，错误索引的频率显着降低。将该方法应用于低碳钢奥形马氏体，成功地重建了奥氏体的形变组织。(C) 2010材料学报Elsevier Ltd.出版。版权所有。
A new method is developed for reconstruction of the local orientation of the parent austenite based on the orientation of lath martensite measured by electron backscattered diffraction. The local orientation of austenite was obtained by least squares fitting as the difference between the experimental data and the predicted martensite orientation was minimal, assuming the specific orientation relationship (OR) between martensite and the parent austenite. First, the average OR between austenite and lath martensite was precisely determined and it was shown that both close packed planes and directions between martensite and the parent austenite deviated by more than 1 degrees in low carbon martensite. The quality of the reconstructed austenite orientation map depended strongly on the OR used for the calculation. When Kurdjumov Sachs (K-S) or Nishiyama-Wasserman (N-W) ORs were used the austenite orientation was frequently mis-indexed as a twin orientation with respect to the true orientation because of the mirror symmetry of (0 1 1)(alpha) stacking in the K S or N-W ORs. In contrast, the frequency of mis-indexing was significantly reduced by using the measured OR, where the close packed planes and directions were not parallel. The deformation structure in austenite was successfully reconstructed by applying the proposed method to ausformed martensite in low carbon steel. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.