Plastic Physics of Defect Mechanics

多晶韧性材料的屈服可以通过位错跨越晶界（GB）的转移来实现，也可以通过残余的GB位错与由于施加应力而在GB近场形核的位错结合来实现。这些现象是由晶界取向和晶界周围多轴应力状态决定的。在本研究中，利用由两个晶粒和一个GB组成的微柱，从纳米压痕的角度研究了位错与GB之间的相互作用。分子动力学模拟还揭示了均匀压缩和非均匀压痕应力状态下的物理位错反应。这些相互作用可以用这里提出的边界相互作用条件来概括。

Yielding of polycrystalline ductile materials can be realized by transfer of dislocation across a grain boundary (GB), or by incorporation between the residual GB dislocation and the dislocations nucleated in the near-field of GB due to the applied stress. These phenomena are determined by the crystallographic orientation and the multiaxial stress state around GB. In the present research, the interaction between dislocations and GB among several defects interactions has been investigated from nanoindentation using a micro-sized pillars consisting of two grains and one GB. Also molecular dynamics simulations revealed the physical dislocation reactions under a uniform compression and a nonuniform indentation stress state.These interactions can be summarized by using a boundary interaction condition proposed here.