Dislocation nucleation from bicrystal interfaces with dissociated structure
Dislocation nucleation from bicrystal interfaces with dissociated structure
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DOI：
10.1016/j.ijplas.2006.03.008
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发表时间：
2007
影响因子：
9.8
通讯作者：
D. Spearot;K. Jacob;D. McDowell
中科院分区：
文献类型：
--
作者：
D. Spearot;K. Jacob;D. McDowell
原子计算被用来模拟部分位错的形核过程中的拉伸变形与解离结构的双晶体界面。具有这种结构的界面主要出现在具有低固有堆垛层错能的材料中。在这项工作中，每个双晶界面的初始结构是使用能量最小化技术细化。分子动力学模拟，然后使用研究在单轴拉伸垂直于边界平面在恒定的应变速率的每个接口的变形。分析的重点是分离的界面结构的位错成核事件之前的演变和由此产生的结构的边界后，发射的部分位错从接口。位错成核主要发生在解离的界面结构单元，而界面特征之间的间距被确定为影响失效模式的重要长度尺度。解离的界面结构和部分位错的成核的演变被发现是类似于在以前的原子的研究中得到的结果的应力依赖性的锁形成包含一个阶梯杆位错。
Atomistic calculations are used to model the nucleation of partial dislocations during a tensile deformation from bicrystal interfaces with dissociated structure. Interfaces with this type of structure occur primarily in materials with low intrinsic stacking fault energies. In this work, the initial structure of each bicrystal interface is refined using energy minimization techniques. Molecular dynamics simulations are then used to study the deformation of each interface in uniaxial tension perpendicular to the boundary plane at a constant strain rate. Analysis focuses on the evolution of the dissociated interface structure prior to the dislocation nucleation event and the resulting structure of the boundary after the emission of partial dislocations from the interface. Dislocation nucleation occurs predominantly at the dissociated interface structural unit, while the spacing between interface features is identified as an important length scale that affects the failure mode. The evolution of the dissociated interface structure and the nucleation of partial dislocations are found to be similar to results obtained in a previous atomistic study of the stress dependence of a lock formation containing a stair-rod dislocation.