Dynamics of curved dislocation ensembles
Dynamics of curved dislocation ensembles
复制标题
弯曲位错系综的动力学
DOI：
10.1103/physrevb.103.174101
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
T. Hochrainer
中科院分区：
文献类型：
--
作者：
I. Groma;P. D. Isp'anovity;T. Hochrainer
建立基于位错的晶体塑性统计连续统理论是材料科学的一个重大挑战。在过去的二十年中，这种理论已经发展为平行边缘位错系统的时间演化。演化方程由单个位错运动方程的系统粗粒化导出，然后应用相场理论的标准形式从位错密度和应力势的泛函中得到。然而，如果可以为弯曲位错系统建立类似的程序，这是一个长期存在的问题。最近通过基于密度的运动曲线运动学理论建立了这种理论的一个重要前提。本文提出了单滑移情况下弯曲位错系统动力学的系统推导方法。为了降低问题的复杂性，对依赖于方向的密度变量采用了类似“偶极子”的近似。这导致了一组闭合的总位错密度、GND密度和所谓的曲率密度的运动演化方程。所得到的方程与边缘位错模型的类比使人们可以推广相场的形式并得到一组封闭的动态演化方程。
To develop a dislocation-based statistical continuum theory of crystal plasticity is a major challenge of materials science. During the last two decades such a theory has been developed for the time evolution of a system of parallel edge dislocations. The evolution equations were derived by a systematic coarse-graining of the equations of motion of the individual dislocations and later retrieved from a functional of the dislocation densities and the stress potential by applying the standard formalism of phase field theories. It is, however, a long standing issue if a similar procedure can be established for curved dislocation systems. An important prerequisite for such a theory has recently been established through a density-based kinematic theory of moving curves. In this paper, an approach is presented for a systematic derivation of the dynamics of systems of curved dislocations in a single slip situation. In order to reduce the complexity of the problem a “dipole” like approximation for the orientation dependent density variables is applied. This leads to a closed set of kinematic evolution equations of total dislocation density, the GND densities, and the so-called curvature density. The analogy of the resulting equations with the edge dislocation model allows one to generalize the phase field formalism and to obtain a closed set of dynamic evolution equations.
影响因子：
1.6
作者：
T. Hochrainer
通讯作者：
T. Hochrainer