Effect of Extrinsic Grain Boundary Dislocations on Mechanical Properties of Ultrafine-Grained Metals by Molecular Dynamics Simulations
Effect of Extrinsic Grain Boundary Dislocations on Mechanical Properties of Ultrafine-Grained Metals by Molecular Dynamics Simulations
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DOI：
10.2320/matertrans.md200810
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发表时间：
2009
影响因子：
1.2
通讯作者：
T. Shimokawa;T. Hiramoto;T. Kinari;Sukenori Shintaku
中科院分区：
文献类型：
--
作者：
T. Shimokawa;T. Hiramoto;T. Kinari;Sukenori Shintaku
采用分子动力学模拟方法研究了非平衡晶界外源晶界位错对超细晶金属力学性能的影响。制备了含裂纹的铝双晶模型和由裂纹尖端撞击的egbd模型。首先，研究了局部晶界结构对egbd调节机制及其应力场的依赖关系。然后，研究了egbd对裂纹尖端位错发射的屏蔽作用，并讨论了非平衡晶界对晶内变形的影响。最后，为了研究egbd与晶间变形之间的关系，对双晶模型施加了剪切载荷。研究发现，外源晶界是晶间变形源，外源晶界的Burgers矢量分量导致晶界各向异性滑动。
The effect of extrinsic grain boundary dislocations (EGBDs) in nonequilibrium grain boundaries on the mechanical properties of ultrafine-grained metals is investigated by molecular dynamics simulations. Aluminum bicrystal models containing cracks and EGBDs impinged from the crack tips are prepared. First, the dependence of the local grain boundary structure on the accommodation mechanism of EGBDs, and on its stress field is studied. Then, the shielding effect of EGBDs on the emissions of dislocations from crack tips is investigated, and the effect of nonequilibrium grain boundaries on the intragranular deformation is discussed. Finally, to investigate the relationship between EGBDs and intergranular deformations, shear loading is applied to the bicrystal models. It is found that extrinsic grain boundaries function as the intergranular deformation source, and the Burgers vector components of the EGBDs lead to anisotropic grain boundary sliding.