Materials Research Letters ( IF 8.3 ) Pub Date : 2020-12-18 , DOI: 10.1080/21663831.2020.1854359 Di Qiu 1 , Pengyang Zhao 2, 3 , Dallas R. Trinkle 4 , Yunzhi Wang 3
The stress-dependent core structures of dislocations for basal slip in magnesium are calculated using ab initio generalized stacking fault energy surface and microscopic phase-field method. The dissociation of dislocation cores exhibits the dependence on the non-shear component in the stress tensor; the Peierls stress is found to either become virtually zero or increase by an order of magnitude, depending on the applied shear stress magnitude and direction. The results, in contrast to the classical Schmid's law for crystal plasticity, are explained using the Escaig stress concept and the resulting implication on plastic deformation is discussed.
IMPACT STATEMENT
Dependence of dislocation core structure on stress is predicted using a microscopic phase-field model with subatomic resolution, revealing non-Schmid behavior together with significant influence on the Peierls stress.
中文翻译:
应力依赖性位错核心结构导致非施密特行为
利用从头算的广义堆垛层错能面和微观相场方法,计算了镁基层滑脱位错的应力相关核心结构。位错核心的解离表现出对应力张量中非剪切分量的依赖性;根据施加的剪切应力的大小和方向,发现Peierls应力实际上变为零或增加一个数量级。与经典的施密德定律有关晶体塑性的定律相反,该结果使用Escaig应力概念进行了解释,并讨论了其对塑性变形的影响。
影响陈述
使用具有亚原子分辨率的微观相场模型预测了位错核心结构对应力的依赖性,揭示了非Schmid行为以及对Peierls应力的显着影响。