论文标题
相位晶体模型中的位错成核
Dislocation nucleation in the phase field crystal model
论文作者
论文摘要
我们使用相位晶体模型来研究在施加的应力场下二维中边缘位错的成核。位错偶极子在施加的应力下与汉堡矢量保护一致。相位场在成核之前正确地解释了弹性能量存储，以及在成核事件中的耗散弛豫。我们表明，晶格不兼容场是对成核事件位置的敏感诊断，以及汉堡矢量和脱位的滑动方向，这些位置将被核定在阈值以上。相位场能的直接计算与晶格不兼容场的信号准确地与成核事件相关。我们表明，与成核位点上解析应力有关的类似Schmid样标准正确预测了临界成核应力。最后，我们提出了三维，以身体为中心的立方晶格的初步结果。相位场允许直接计算位错线和循环的晶格不兼容张量。
We use the phase field crystal model to study nucleation of edge dislocations in two dimensions under an applied stress field. A dislocation dipole nucleates under the applied stress, consistent with Burgers vector conservation. The phase field correctly accounts for elastic energy storage prior to nucleation, and for dissipative relaxation during the nucleation event. We show that a lattice incompatibility field is a sensitive diagnostic of the location of the nucleation event, and of the Burgers vector and slip direction of the dislocations that will be nucleated above threshold. A direct calculation of the phase field energy accurately correlates with the nucleation event, as signaled by the lattice incompatibility field. We show that a Schmid-like criterion concerning the resolved stress at the nucleation site correctly predicts the critical nucleation stress. Finally, we present preliminary results for a three-dimensional, body-centered cubic lattice. The phase field allows a direct computation of the lattice incompatibility tensor for both dislocation lines and loops.
