Mechanisms of exceptional ductility of magnesium single crystal during deformation at room temperature: Multiple twinning and dynamic recrystallization
Mechanisms of exceptional ductility of magnesium single crystal during deformation at room temperature: Multiple twinning and dynamic recrystallization
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DOI：
10.1016/j.actamat.2014.04.066
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发表时间：
2014-09-01
期刊：
影响因子：
9.4
通讯作者：
Gottstein, Guenter
中科院分区：
文献类型：
--
作者：
Molodov, Konstantin D.;Al-Samman, Talal;Gottstein, Guenter
在室温下，对特殊取向的镁单晶进行了c轴向沿着（11（2）over bar 0）方向的平面应变压缩。样品变形至对数最终应变为-1，说明了异常高的可成形性，即使由于相对于变形几何形状的加载取向而最初抑制了基底和棱柱滑移。宏观{10（1）过棒2}伸展孪晶在变形的早期阶段大量形成，完全消耗了整个样品，导致新的软滑移取向。其他的结对活动以二级和三级结对的形式进行。在变形的某些高级阶段，在与初级拉伸孪晶基体内的前{10（1）过棒1}收缩孪晶相关的许多带内观察到新形成的（再结晶的）晶粒。再结晶晶粒围绕其母孪晶的c轴旋转平均30度角，导致取向从理想孪晶取向的第二类型（（11（2）over bar 0））棱柱纤维向再结晶晶粒的第一类型（（10（1）over bar 0））棱柱纤维移位。这导致在最终应变下织构强度的显著减弱，以及在取向差分布中30度晶界的高频峰。所得到的结果进行了讨论，相对于在室温下的连续动态再结晶多次孪生过程中的织构演变。(C)2014 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
Specially oriented magnesium single crystals were subjected to plane strain compression along the (11 (2) over bar0) direction in c-axis extension at ambient temperature. The samples deformed up to a logarithmic final strain of -1, illustrating exceptionally high formability, even though basal and prismatic slip were initially inhibited due to the loading orientation with respect to the deformation geometry. Macroscopic {10 (1) over bar2} extension twins forming massively during early stages of deformation completely consumed the whole sample, resulting in new soft orientations for slip. Additional twinning events took place in the form of secondary and tertiary twinning. At somewhat advanced stages of deformation, newly formed (recrystallized) grains were observed within numerous bands associated with former {10 (1) over bar1} contraction twins within the primary extension twinned matrix. Recrystallized grains were rotated around the c-axis of their parent twin by an average angle of 30 degrees, resulting in a shift of orientations from the second type ((11 (2) over bar0)) prismatic fiber of ideal twin orientations towards the first type ((10 (1) over bar0)) prismatic fiber of recrystallized grains. This led to a substantial weakening of the texture intensity at the final strain, as well as a high frequency peak of 30 degrees grain boundaries in the misorientation distribution. The obtained results are discussed with respect to the texture evolution during multiple twinning in conjunction with continuous dynamic recrystallization at room temperature. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.