Evidence of grain boundary dislocation step motion associated to shear-coupled grain boundary migration
Evidence of grain boundary dislocation step motion associated to shear-coupled grain boundary migration
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DOI：
10.1080/14786435.2012.760760
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发表时间：
2013-04
影响因子：
1.6
通讯作者：
Armin Rajabzadeh;Marc Legros;Nicolas Combe;F. Mompiou;D. Molodov
中科院分区：
文献类型：
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作者：
Armin Rajabzadeh;Marc Legros;Nicolas Combe;F. Mompiou;D. Molodov
摘要本文报道了76.4双晶和多晶铝样品在中温（400 ℃）下原位透射电子显微镜应变实验中晶界（GB）介导塑性的动态观察结果。我们表明，GB迁移发生的基本GB位错台阶的横向运动。晶界位错台阶的积累最终形成宏观台阶。这一观察结果与GB位错台阶通常在大角度GB中类似于孪生或马氏体相变的想法一致。使用基准标记和图像相关性测量耦合因子，即由台阶的运动产生的应变。迁移过程涉及不同类型的GB位错步骤，产生平行（耦合因子）和垂直于GB平面的不同量的应变。
Abstract The present work reports dynamical observations of the grain boundary (GB)-mediated plasticity during in situ transmission electron microscopy straining experiments at moderate temperature (400 C) both in a 76.4 bicrystalline and a polycrystalline Al sample. We show that the GB migration occurs by the lateral motion of elementary GB dislocation steps. The accumulation of GB dislocation steps eventually form macro-steps. This observation agrees with the idea that GB dislocation steps generally operate in high angle GBs similarly as in twinning or martensitic transformations. The coupling factor, i.e. the strain produced by the motion of the steps was measured using fiducial markers and image correlation. The migration process involves different types of GB dislocation steps, producing different amounts of strain both parallel (coupling factor) and perpendicular to the GB plane.