Hierarchical dislocation nucleation controlled by internal stress in nanocrystalline copper
Hierarchical dislocation nucleation controlled by internal stress in nanocrystalline copper
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DOI：
10.1063/1.4811791
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发表时间：
2013-06
影响因子：
4
通讯作者：
Yong-bo Guo;Tao Xu;Mo Li
中科院分区：
文献类型：
--
作者：
Yong-bo Guo;Tao Xu;Mo Li
位错成核是纳米晶材料力学性能的基础。在晶粒尺寸小于100 nm时，观察到位错主要从晶界成核。在这里，我们报告的过程中产生的位错层次起源于不同的微观结构成分在纳米铜从原子模拟。我们表明，顺序成核是由内部应力与微观结构实体：首先从顶点，内部应力是最高的，其次从三重结，然后从晶界与较低的内部应力。这种联系为数控材料的工程力学性能提供了有效的解决方案。
Dislocation nucleation is fundamental to mechanical properties of nanocrystalline (nc) materials. At grain size less than 100 nm, dislocations have been observed to nucleate predominantly from grain boundaries. Here, we report a process of dislocation generation originated hierarchically from different microstructural components in nc-copper from an atomistic simulation. We show that the sequential nucleation is dictated by the internal stress associated with the microstructural entities: First from the vertex points where internal stress is highest, next from triple junctions, and then from grain boundaries with lower internal stress. This connection suggests effective solutions for engineering mechanical properties of nc materials.