The paper reports on a molecular dynamics simulation of plastic deformation in polycrystalline titanium under scratch testing with explicit account of crystallographic orientations determined by electron backscatter diffraction for individual Ti grains. The simulation shows that the presence of a grain boundary breaks the lattice translation invariance and induces a constrained strain zone in which the deformation changes its dislocation mechanism for rotations such that misoriented local regions appear near the grain boundary. The pattern of consistent dynamic rotations of atoms near the grain boundary is governed by the crystallographic orientation of grains. If the indenter sliding direction coincides with one of the easy slip directions of a loaded grain, the material in the grain boundary region is fragmented and atomic clusters move along the grain boundary plane from the surface deep into the material. The simulation results allow us to explain why the profile of scratches differs depending on the scratching direction.

中文翻译：

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划痕试验下晶界在多晶钛旋转变形中的作用

该论文报告了在划痕测试下多晶钛塑性变形的分子动力学模拟，并明确考虑了由单个 Ti 晶粒的电子背散射衍射确定的晶体取向。模拟表明，晶界的存在打破了晶格平移不变性并产生了一个受约束的应变区，在该区中，变形会改变其旋转的位错机制，从而导致在晶界附近出现取向错误的局部区域。晶界附近原子的一致动态旋转模式受晶粒的晶体取向控制。如果压头滑动方向与加载谷物的易滑动方向之一重合，晶界区域的材料被破碎，原子团沿着晶界平面从表面深入材料。模拟结果使我们能够解释为什么划痕的轮廓因划痕方向而异。