Twin recrystallization mechanisms in magnesium-rare earth alloys
Twin recrystallization mechanisms in magnesium-rare earth alloys
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DOI：
10.1016/j.actamat.2015.05.044
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发表时间：
2015-09-01
期刊：
影响因子：
9.4
通讯作者：
Al-Samman, T.
中科院分区：
文献类型：
--
作者：
Basu, I.;Al-Samman, T.
具有基型起始织构的二元Mg-1wt.%Gd和Mg-1wt.%Ce变形合金进行了平面应变压缩。C轴拉伸(平面压缩)和c轴压缩(通过厚度压缩)的特殊取向试件的变形分别为6%和13%。Mg-1Gd在面内压缩(IPC)下的形变导致了尖锐的“棱柱状纤维”织构的演化，而Mg-1Ce则表现出较弱的基面织构。在穿透厚度压缩(TTC)的情况下，Mg-1Gd产生裂开的基组分，而Mg-1Ce产生较弱的基组分，并有较大的离基扩展。在微观结构上，在IPC过程中，Mg-1Gd表现出明显的{10(1)Over bar2}拉伸孪晶和{10(1)Over bar1}压缩孪晶，而ITC模式下大量的{10(1)Over bar1}压缩孪晶。大多数压缩双胞胎经历了第二代{10(1)Over bar2}拉伸孪生，产生了{10(1)Over bar1}-{10(1)Over bar2}双胞胎。挤压和双孪晶区表现出强烈的滑移活动，导致形成细小的回复亚结构。相反，Mg-1Ce表现出传统的形变响应，孪晶以{10(1)对bar2}拉伸型为主。退火使变形织构成分保持不变，织构弱化。Mg-1Gd的再结晶在压缩孪晶和孪晶中不连续地开始，在较高的温度下表现出良好的生长行为，消耗了仍然变形的母体和拉伸孪晶。Mg-1Ce表现出连续的再结晶，表现为取向软拉伸孪晶的恢复和长大以及颗粒附近的形核。(C)2015 Acta Materialia Inc.由爱思唯尔有限公司出版。版权所有。
Binary Mg-1 wt.% Gd and Mg-1 wt.% Ce wrought alloys, with basal type starting texture, are subjected to plane strain compression. Specially oriented specimens invoking c-axis extension (In Plane Compression) and c-axis compression (through thickness compression) were deformed to 6% and 13% respectively. Deformation in Mg-1Gd under in plane compression (IPC) led to evolution of sharp 'prismatic fiber' texture, whereas a weak basal texture was witnessed for Mg-1 Ce. In case of through thickness compression (TTC), Mg-1Gd gave rise to a split basal component, whereas Mg-1Ce resulted in a weak basal component with large off-basal spread. Microstructurally, Mg-1Gd displayed unequivocal activation of both {10 (1) over bar2} tension twinning and {10 (1) over bar1} compression twinning during IPC, while profuse {10 (1) over bar1} compression twinning for the ITC mode. Majority of the compression twins underwent second generation {10 (1) over bar2} tension twinning to give rise to {10 (1) over bar1}-{10 (1) over bar2} double twins. Compression and double twinned regions showed strong slip activity leading to the formation of fine recovered sub-structure. On the contrary, Mg-1Ce exhibited a conventional deformation response with twinning being predominantly of {10 (1) over bar2} tension type. Annealing led to preservation of the deformation texture components along with strong texture weakening. Recrystallization in Mg-1Gd commenced discontinuously in compression and double twins, which at higher temperatures showed favorable growth behavior consuming the still deformed matrix and tension twins. Mg-1Ce displayed continuous recrystallization marked by recovery and growth of orientationally soft tension twins along with nucleation in the vicinity of particles. (C) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.