Unveiling the underlying mechanism of forming edge cracks upon high strain-rate rolling of magnesium alloy
Unveiling the underlying mechanism of forming edge cracks upon high strain-rate rolling of magnesium alloy
复制标题
揭示镁合金高应变率轧制时形成边缘裂纹的根本机制
DOI：
10.1016/j.jmst.2020.03.006
复制
发表时间：
2020-08-01
影响因子：
10.9
通讯作者：
Liu, Wenhui
中科院分区：
文献类型：
--
作者：
Zhu, Biwu;Liu, Xiao;Liu, Wenhui
在本研究中，采用高应变速率轧制(>；=10 S(-1))已成功地在一次道次中获得了高变形率82%的细晶组织的镁铝锌合金板材。探讨了一次边裂纹和二次边裂纹的形成机理。结果表明，亚晶诱发的动态再结晶倾向于钝化裂纹，而孪生诱发的动态再结晶主要发生在尖端附近。钝裂纹出射位错的运动受到DRX晶界的抑制。这一方面增加了局部加工硬化，另一方面导致晶界应力集中，特别是在三重结合处，导致二次裂纹的形成。(C)2020由爱思唯尔有限公司代表《材料科学与技术杂志》编辑部出版。
In the current study, high strain-rate rolling (>= 10 s(-1)) has been successfully employed to produce Mg3Al-1Zn alloy sheets to a high reduction of 82% with a fine grain structure in a single pass. The underlying mechanism of forming primary and secondary edge cracks has been investigated. It is found that dynamic recrystallization (DRX) induced by subgrains tends to blunt cracks, while twinning-induced DRX is mainly observed around sharp crack tips. The motion of emitted dislocations from blunted cracks is inhibited by the DRX grain boundaries. This, on one hand, increases local work hardening, and on the other hand, causes stress concentration along grain boundaries especially in the triple junctions leading to the formation of secondary cracks. (C) 2020 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.