Woodward C, Rao S I
Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright Patterson Air Force Base, Dayton, Ohio 45433-7817, USA.
Phys Rev Lett. 2002 May 27;88(21):216402. doi: 10.1103/PhysRevLett.88.216402. Epub 2002 May 13.
We report the first ab initio density-functional study of the strain field and Peierls stress of isolated <111> screw dislocations in bcc Mo and Ta. The local dislocation strain field is self-consistently coupled to the long-range elastic field using a flexible boundary condition method. This reduces the mesoscopic atomistic calculation to one involving only degrees of freedom near the dislocation core. The predicted equilibrium core for Mo is significantly different from previous atomistic results and the Peierls stress shows significant non-Schmid behavior as expected for the bcc metals.
我们报告了对体心立方结构的钼（Mo）和钽（Ta）中孤立的<111>螺旋位错的应变场和派尔斯应力进行的首次从头算密度泛函研究。使用灵活边界条件方法，将局部位错应变场与长程弹性场自洽耦合。这将介观原子计算简化为仅涉及位错核心附近自由度的计算。预测的钼的平衡核心与先前的原子计算结果有显著差异，并且派尔斯应力表现出明显的非施密德行为，这与体心立方金属的预期一致。
