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Improved phase field model of dislocation intersections
npj Computational Materials ( IF 9.7 ) Pub Date : 2018-04-11 , DOI: 10.1038/s41524-018-0075-x
Songlin Zheng , Dongchang Zheng , Yong Ni , Linghui He

Revealing the long-range elastic interaction and short-range core reaction between intersecting dislocations is crucial to the understanding of dislocation-based strain hardening mechanisms in crystalline solids. Phase field model has shown great potential in modeling dislocation dynamics by both employing the continuum microelasticity theory to describe the elastic interactions and incorporating the γ-surface into the crystalline energy to enable the core reactions. Since the crystalline energy is approximately formulated by linear superposition of interplanar potential of each slip plane in the previous phase field model, it does not fully account for the reactions between dislocations gliding in intersecting slip planes. In this study, an improved phase field model of dislocation intersections is proposed through updating the crystalline energy by coupling the potential of two intersecting planes, and then applied to study the collinear interaction followed by comparison with the previous simulation result using discrete dislocation dynamics. Collinear annihilation captured only in the improved phase field model is found to strongly affect the junction formation and plastic flow in multislip systems. The results indicate that the improvement is essential for phase field model of dislocation intersections.



中文翻译:

错位相交的改进相场模型

揭示相交位错之间的长程弹性相互作用和短程核心反应,对于理解晶体固体中基于位错的应变硬化机制至关重要。相场模型通过使用连续微弹性理论描述弹性相互作用并结合了γ,在位错动力学建模方面显示出巨大潜力。-表面转化为结晶能以使核反应发生。由于在先前的相场模型中,结晶能量是由每个滑移面的平面内电位的线性叠加近似地公式化的,因此它不能完全解决滑移在相交滑移面中的位错之间的反应。在这项研究中,提出了一种改进的位错相交相场模型,该方法通过耦合两个相交平面的电势来更新晶体能量,然后用于研究共线相互作用,然后与离散位错动力学的先前模拟结果进行比较。发现仅在改进的相场模型中捕获的共线an灭严重影响多滑系统中的结形成和塑性流动。

更新日期:2018-04-11
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