An insight into the role of the grain boundary in plastic deformation by means of a bicrystalline pillar compression test and atomistic simulation
An insight into the role of the grain boundary in plastic deformation by means of a bicrystalline pillar compression test and atomistic simulation
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DOI：
10.1016/j.actamat.2013.08.056
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发表时间：
2013-11-01
期刊：
影响因子：
9.4
通讯作者：
Bamoush, Afrooz
中科院分区：
文献类型：
--
作者：
Kheradmand, Nousha;Vehoff, Horst;Bamoush, Afrooz
结合实验和分子动力学（MD）模拟被用来调查的位错与选定的晶界（GB）在双晶柱（BCP）的相互作用与组件晶体取向为单滑移和多滑移。作为参考，具有相同取向的单晶柱也被测试并与BCP进行比较。与实验相同的取向用于在MD模拟中生成模型。此外，电子背散射衍射（EBSD）测量的支柱的横截面上进行调查的晶格旋转与过剩位错密度。当组分晶体的尺寸减小到1 μ m以下时，观察到BCP的机械行为的明显变化。这些小BCP的EBSD分析表明，在GB附近的错误取向的增加。MD模拟为位错成核过程以及BCP与GB的相互作用提供了原子学见解。在这些观察的基础上，它的结论是，在小于1 μ m的BCP的位错GB相互作用比位错位错相互作用起着更重要的作用。(C)2013 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
A combination of experimental and molecular dynamics (MD) simulations is used to investigate the interaction of dislocations with a selected grain boundary (GB) in bicrystalline pillars (BCPs) with component crystals oriented for single slip and multiple slip. As a reference, single-crystalline pillars with the same orientations are also tested and compared with the BCPs. Orientations identical to the experiments are used to generate models in MD simulations. Further, electron backscatter diffraction (EBSD) measurements on the cross-section of the pillars are performed to investigate the crystal lattice rotation in correlation with the excess dislocation density. A clear change in mechanical behavior of the BCP was observed when the size of the component crystals reduced below 1 mu m. The EBSD analyses of these small BCPs showed an increase in the misorientation in the vicinity of the GB. MD simulation provided atomistic insights into the dislocation nucleation process and the BCPs' interaction with the GB. On the basis of these observations, it is concluded that in BCPs smaller than 1 mu m the dislocation-GB interaction plays a more crucial role than the dislocation-dislocation interaction. (C) 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.