Crystallographic analysis on atomic-plane parallelisms between bcc precipitates and hcp matrix in recrystallized Zr-2.5Nb alloys
Crystallographic analysis on atomic-plane parallelisms between bcc precipitates and hcp matrix in recrystallized Zr-2.5Nb alloys
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DOI：
10.1016/j.actamat.2016.12.053
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发表时间：
2017-03
期刊：
影响因子：
9.4
通讯作者：
Y. Matsukawa;I. Okuma;H. Muta;Y. Shinohara;R. Suzue;Huilong Yang;T. Maruyama;T. Toyama;Jingjie Shen;Yanfen Li;Y. Satoh;S. Yamanaka;H. Abe
中科院分区：
文献类型：
--
作者：
Y. Matsukawa;I. Okuma;H. Muta;Y. Shinohara;R. Suzue;Huilong Yang;T. Maruyama;T. Toyama;Jingjie Shen;Yanfen Li;Y. Satoh;S. Yamanaka;H. Abe
嵌入六方密堆积 (hcp) 基体中的体心立方 (bcc) 析出物的晶体取向通常假定遵循所谓的 Burgers 取向关系；然而，在析出与基体再结晶同时发生的情况下，可能无法维持这种取向关系。 Zr-2.5Nb合金就是这种情况的典型例子。在本研究中，通过电子背散射衍射（EBSD）和透射菊池衍射（TKD）分析了完全再结晶hcp Zr基体中bcc沉淀物（富Nb β 2 相和富Zr β 1 相）的晶体取向。根据EBSD/TKD测定的欧拉角，一一检查原子平面的平行度。对每种组合物的 100 个沉淀物进行分析。富 Nb 析出物的晶体取向实际上是随机的，而 28% 的富 Zr 析出物遵循 Burgers 取向关系。此外，其滑移面（{110}或{112}）与hcp Zr基体的滑移面（{10 1¯ 0}）平行的富Nb析出物的比例不大于5%。这些结果支持了我们之前研究的初步结论，即铌析出物是理想的奥罗万型强障碍物，阻止由于晶体失配而导致的滑移位错，尽管它们在剪切模量方面比基体软。
The crystal orientation of body centered cubic (bcc) precipitates embedded in hexagonal close packed (hcp) matrix is usually assumed to follow the so-called Burgers orientation relationship; however, this orientation relationship may not be maintained in the case where the precipitation occurs in parallel with the recrystallization of matrix. The Zr-2.5 Nb alloy is a typical example of such a case. In the present study crystal orientations of bcc precipitates (Nb-rich β 2 phase and Zr-rich β 1 phase) in fully recrystallized hcp Zr matrix have been analyzed by means of electron backscatter diffraction (EBSD) and transmission Kikuchi diffraction (TKD). Based on the Euler angles determined by EBSD/TKD, the parallelism of atomic planes was examined one by one. The analysis was performed on 100 precipitates for each composition. The crystal orientations of the Nb-rich precipitates were practically random, whereas 28% of the Zr-rich precipitates followed the Burgers orientation relationship. Moreover, the fraction of the Nb-rich precipitates whose slip planes, either {110} or {112}, were parallel to those of the hcp Zr matrix,{10 1¯ 0}, was no greater than 5%. These results support a tentative conclusion of our previous study that the Nb precipitates are ideal Orowan type strong obstacles against gliding dislocations due to the crystal mismatch, even though they are softer than the matrix in terms of shear modulus.