The influence of a secondary twin on the detwinning deformation of a primary twin in Mg-3Al-1Zn alloy

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• 作者：Yunchang Xin ; ^{ycxin@cqu.edu.cn" class="auth_mail} ; Xiaojun Zhou ; Liangchen Lv ; Qing Liu
• 关键词：Mg alloy ; Strengthening ; Twinning ; Detwinning
• 刊名：Materials Science and Engineering: A
• 出版年：12 June 2014
• 年：2014
• 卷：606
• 期：Complete
• 页码：81-91
• 全文大小：8148 K

文摘

In the present paper, the influence of a $\left\{10\overline{1}2\right\}$–$\left\{10\overline{1}2\right\}$ secondary twin on detwinning of a $\left\{10\overline{1}2\right\}$ primary twin is systematically investigated by compression along the normal direction (ND) of pre-strained samples at room temperature. Samples containing both a $\left\{10\overline{1}2\right\}$ primary twin and a $\left\{10\overline{1}2\right\}$–$\left\{10\overline{1}2\right\}$ secondary twin are prepared by pre-compression along the transverse direction (TD) and subsequent re-compression along the rolling direction (RD) of a hot-rolled AZ31 Mg alloy plate at room temperature. Our results show that the introduction of a $\left\{10\overline{1}2\right\}$–$\left\{10\overline{1}2\right\}$ secondary twin into the primary twin can enhance the compression yield strength along the ND. During compression along the ND, the $\left\{10\overline{1}2\right\}$–$\left\{10\overline{1}2\right\}$ secondary twin mainly deforms by $\left\{10\overline{1}2\right\}$ twinning, forming a $\left\{10\overline{1}2\right\}$–$\left\{10\overline{1}2\right\}$–$\left\{10\overline{1}2\right\}$ ternary twin, while detwinning of the $\left\{10\stackrel{-}{1}2\right\}$ primary twin also takes place. When a $\left\{10\overline{1}2\right\}$–$\left\{10\overline{1}2\right\}$ secondary twin happens to totally separate a $\left\{10\overline{1}2\right\}$ primary twin from the matrix, it can serve as a barrier to impede detwinning of this $\left\{10\overline{1}2\right\}$ primary twin. The $\left\{10\overline{1}2\right\}$ twinning in a $\left\{10\overline{1}2\right\}$–$\left\{10\overline{1}2\right\}$ secondary twin can induce a preferred distribution of prismatic planes in twinned regions, which is closely related to the activation of preferential twin variants.