论文标题
相位场晶体模型中的弹性与相场驱动运动
Elasticity versus phase field driven motion in the phase field crystal model
论文作者
论文摘要
讨论了与材料质量识别相位晶体理论中的相位场的固有不一致性，同时讨论了材料失真。在目前的实现中，相位场晶体中的弹性松弛通过耗散渗透模式在扩散的时间尺度上发生。固体弹性中包含的同一相位失真驱动扩散运动，导致相位场晶体的非物理松弛。我们提出了两种替代理论来解决这一缺点。在第一种情况下，假定相位场仅确定弹性失真的不兼容部分，因此可以自由指定额外的兼容失真，以便始终满足机械平衡（在准静态极限下）。位错偶极子情况下的新模型的数值解显示，与经典相位场晶体模型不同，它可以说明偶极子中两个位错的相对运动的已知定律。在这个新理论中，兼容菌株的物理起源尚待指定。因此，提出了第二种理论，其中独立失真和相位场之间的明确耦合解释了两者中波动的放松的时间依赖性。还提供了其实施的初步细节。
The inherent inconsistency in identifying the phase field in the phase field crystal Theory with the material mass and, simultaneously, with material distortion is discussed. In its current implementation, elastic relaxation in the phase field crystal occurs on a diffusive time scale through a dissipative permeation mode. The very same phase field distortion that is included in solid elasticity drives diffusive motion, resulting in a non physical relaxation of the phase field crystal. We present two alternative theories to remedy this shortcoming. In the first case, it is assumed that the phase field only determines the incompatible part of the elastic distortion, and therefore one is free to specify an additional compatible distortion so as to satisfy mechanical equilibrium at all times (in the quasi static limit). A numerical solution of the new model for the case of a dislocation dipole shows that, unlike the classical phase field crystal model, it can account for the known law of relative motion of the two dislocations in the dipole. The physical origin of the compatible strain in this new theory remains to be specified. Therefore, a second theory is presented in which an explicit coupling between independent distortion and phase field accounts for the time dependence of the relaxation of fluctuations in both. Preliminary details of its implementation are also given.
