Competing deformation mechanisms in nanocrystalline metals and alloys: Coupled motion versus grain boundary sliding
Competing deformation mechanisms in nanocrystalline metals and alloys: Coupled motion versus grain boundary sliding
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DOI：
10.1016/j.actamat.2012.07.044
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发表时间：
2012-10
期刊：
影响因子：
9.4
通讯作者：
J. Schäfer;K. Albe
中科院分区：
文献类型：
--
作者：
J. Schäfer;K. Albe
采用原子尺度的计算机模拟方法，研究了纳米Pd、Cu以及分相体系Cu-Nb、Cu-Fe的塑性变形。微观组织的选择是为了促进细观晶界的滑动。研究了偏析溶质对变形机制的影响，比较了不同情况下的溶质分布。研究发现，介观晶界滑移和耦合晶界运动之间的竞争受偏析溶质的浓度和分布的控制。通过对微观组织演变和位错活动的分析，将原子溶质分布与变形机制联系起来，解释了观察到的应力应变行为。对法向晶界运动的详细分析揭示了粘滑行为和耦合因子，这与双晶模拟的结果一致。
Plastic deformation of nanocrystalline Pd and Cu as well as the demixing systems Cu–Nb and Cu–Fe is studied by means of atomic-scale computer simulations. The microstructures are specifically chosen to facilitate mesoscopic grain boundary sliding. The influence of segregating solutes on the deformation mechanisms is studied and different cases of solute distributions are compared. We find that the competition between mesoscopic grain boundary sliding and coupled grain boundary motion is controlled by the concentration and distribution of segregating solutes. By analyzing the microstructural evolution and dislocation activity we make a connection between the atomistic solute distribution and the mechanisms of deformation, explaining the observed stress–strain behavior. The detailed analysis of the normal grain boundary motion reveals a stick–slip behavior and a coupling factor which is consistent with results from bicrystal simulations.