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Stress effects on the energy barrier and mechanisms of cross-slip in FCC nickel
Journal of the Mechanics and Physics of Solids ( IF 5.3 ) Pub Date : 2020-08-05 , DOI: 10.1016/j.jmps.2020.104105
William P. Kuykendall , Yifan Wang , Wei Cai

The energy barrier for homogeneous cross-slip of a screw dislocation in face-centered cubic (FCC) nickel is calculated using atomistic simulations as a function of the Escaig stress on the glide plane, the Escaig stress on the cross-slip plane, and the Schmid stress on the cross-slip plane. Two cross-slip mechanisms, Friedel-Escaig (FE) and Fleischer, are examined and their energy barriers are calculated for a large number of stress combinations. For each mechanism, the energy barrier as a function of three stress components can be reduced into a one-dimensional function of an effective stress. The stress domains in which FE and Fleischer mechanisms operate respectively are determined. The FE mechanism dominates when the Escaig stress on the glide plane (in the direction that reduces the stacking fault width) is the largest stress component. Increasing the Schmid stress and Escaig stress (in the direction that expands the stacking fault width) on the cross slip plane promotes the Fleischer mechanism. The cross slip energy barrier functions obtained here can be used as input functions for computing cross slip rates in mesoscale dislocation dynamics simulations.



中文翻译:

应力对FCC镍的能垒和交叉滑动机理的影响

使用原子模拟模拟滑面平面上的Escaig应力,滑面平面上的Escaig应力和平面滑移面上的Escaig应力,可以计算面心立方(FCC)镍中螺钉位错的均匀错位的能垒。在跨滑平面上施加施密特应力。检查了两种交叉滑动机制,即Friedel-Escaig(FE)和Fleischer,并针对大量应力组合计算了它们的能垒。对于每种机制,可以将作为三个应力分量的函数的能垒减小为有效应力的一维函数。确定了FE和Fleischer机制分别在其中工作的应力域。当滑行面上的Escaig应力(沿减小堆垛层错宽度的方向)是最大应力分量时,FE机制起主导作用。在横向滑移面上增加Schmid应力和Escaig应力(沿扩大堆垛层错宽度的方向)会促进Fleischer机制。此处获得的交叉滑动能垒函数可用作中尺度位错动力学模拟中计算交叉滑动率的输入函数。

更新日期:2020-08-05
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