A mesoscale model is introduced to study the dynamics of material defects lying at interface junctions. The proposed framework couples the dynamics of discrete dislocation and disclination lines. Disclinations are expected to be natural defects at interface junctions; their presence serving the purpose of accommodating discontinuities in rotation fields at material interface junctions. Crystallography-based rules are proposed to describe the kinematics of disclination motion. A discrete-continuous couple-stress framework, in which discrete defect lines are introduced as plastic eigenstrains and eigencurvatures, is proposed to explicitly follow the dynamics of interfacial defects. The framework is then applied to study $\left (10\bar {1}2\right)$ twin transverse propagation and thickening in magnesium. Focusing first on the case of a twin domain, It is shown that a disclination based representation of twin domains allows for an appropriate mechanistic description of the kinematics of shear transformations. In what concerns twin thickening, the stability of defects at twin interfaces is further studied. To this end, a 3D crater lying on a twin interface is described as a dipole of disclination loops. Upon self-relaxation, it is found that out of plane motion of disclinations followed by the nucleation of twinning dislocations can be activated; thereby showing that conservative non-planar motion of disclinations can be thermodynamically favorable; mechanism that had been postulated some 50 years ago.

中文翻译：

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GD ³：广义离散缺陷动力学

引入了中尺度模型来研究位于界面交界处的材料缺陷的动力学。拟议的框架耦合离散位错和错位线的动力学。错位现象是界面交界处的自然缺陷。它们的存在是为了适应材料界面交界处旋转场中的不连续性。提出了基于晶体学的规则来描述错位运动的运动学。提出了离散连续的耦合应力框架，其中引入离散的缺陷线作为塑性特征应变和特征曲率，以明确地跟踪界面缺陷的动力学。然后将该框架应用于研究镁的\\左（10 \ bar {1} 2 \右）$双横向传播和增厚。首先关注孪生域的情况，结果表明，基于向错的孪生域表示可以对剪切变换的运动学进行适当的力学描述。关于孪晶增厚，进一步研究了孪晶界面处缺陷的稳定性。为此，位于孪生界面上的3D陨石坑被描述为旋错环的偶极子。在自我放松时，发现错位的平面外运动继之以孪晶位错的成核可以被激活。从而表明，向错的保守的非平面运动在热力学上是有利的；大约50年前已提出的机制。