Microband/twin recrystallization during back extrusion of AZ31 magnesium
Microband/twin recrystallization during back extrusion of AZ31 magnesium
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DOI：
10.1016/j.msea.2017.09.134
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发表时间：
2017-12-21
期刊：
影响因子：
6.4
通讯作者：
Zarei-Hanzaki, A.
中科院分区：
文献类型：
--
作者：
Fatemi, S. M.;Zarei-Hanzaki, A.
通过光学和扫描电子显微镜以及电子背散射衍射分析，研究了 AZ31 镁合金剧烈塑性变形过程中微带和孪晶动态再结晶的发生。微观结构观察表明，微带的波状边界已经扩散并在母带内产生新的边界。此外，通过孪晶破碎机制形成的晶粒往往会获得随机取向。此外，横向边界将双胞胎分割成超细和纳米级尺寸的区域。还认识到一种新的所谓“双辅助”晶粒细化机制，其采用与传统再结晶机制产生的取向不同的取向。后一种机制有助于镁合金热机械加工过程中的织构弱化。
The occurrence of dynamic recrystallization of microband and twins during severe plastic deformation of an AZ31 magnesium alloy was studied through optical and scanning electron microcopy as well as electron back scatter diffraction analyses. Microstructural observations indicated that the wavy boundaries of the microbands had diffused out and generated new boundaries within parent bands. Also the grains formed through twin fragmentation mechanism tend to acquire random orientations. Moreover, transverse boundaries segmented the twins into regions of ultra-fine and nano-scale size. A new so-called "twin-assisted" grain refinement mechanism was also recognized which adopted the orientations different from those produced by conventional re crystallization mechanisms. The latter mechanism is useful to assist texture weakening during thermomechanical processes of magnesium alloys.