Object kinetic Montecarlo (OkMC) is a fundamental tool for modeling defect evolution in volumes and times far beyond atomistic models. The elastic interaction between defects is classically considered using a dipolar approximation but this approach is limited to simple cases and can be inaccurate for large and close interacting defects. In this work a novel framework is proposed to include "exact" elastic interactions between defects in OkMC valid for any type of defect and anisotropic media. In this method, the elastic interaction energy of a defect is computed by volume integration of its elastic strain multiplied by the stress created by all the other defects, being both fields obtained numerically using a FFT solver. The resulting interaction energies reproduce analytical elastic solutions and show the limited accuracy of dipole approaches for close and large defects. The OkMC framework proposed is used to simulate the evolution in space and time of self-interstitial atoms and dislocation loops in iron. It is found that including the anisotropy has a quantitative effect in the evolution of all the type of defects studied. Regarding dislocation loops, it is observed that using the "exact" interaction energy result in higher interactions than using the dipole approximation for close loops.

翻译：物体动力学蒙特卡洛（OkMC）是模拟远超越原子尺度体积与时间范围内缺陷演化的基础工具。缺陷间的弹性相互作用传统上采用偶极近似进行处理，但该方法仅适用于简单情形，且对于大尺寸及近距离相互作用的缺陷可能产生较大误差。本研究提出一种新型框架，可在OkMC中纳入缺陷间"精确"弹性相互作用，适用于任意类型缺陷及各向异性介质。该方法通过体积积分计算缺陷的弹性相互作用能：将缺陷的弹性应变与所有其他缺陷产生的应力相乘后积分，两者均通过FFT求解器数值获取。所得相互作用能可再现解析弹性解，并揭示偶极近似方法在处理近距离大尺寸缺陷时的精度局限性。所提出的OkMC框架被用于模拟铁中自间隙原子与位错环在空间与时间上的演化。研究发现，考虑各向异性对所研究各类缺陷的演化均产生定量影响。对于位错环，观察到使用"精确"相互作用能时，近距离环间的相互作用强度高于偶极近似结果。