Abstract We present multi-scale simulation of plastic deformation in molybdenum. The temperature-dependent mobility functions of screw and edge dislocations were calculated from molecular dynamics simulation with two different interatomic potentials. The simulations of screw dislocation movement under applied shear stress revealed that the process can proceed in two different regimes: through thermally activated motion and athermal motion. Hence, the dislocation velocity depends on the shear stress in a non-trivial way. We took this fact into account during calculation of the mobility functions and their implementation in the dislocation dynamics (DD) model. Such model allows us to simulate plastic deformation with consideration of temperature effect on the dislocation mobility. Here we discuss the changes in DD predictions depending on the input parameters obtained from the atomistic simulation. As the main result, we report the yield stress calculated for a single crystal of molybdenum at various temperatures, strain rates, and dislocation densities. Thoroughly discussed comparison of the simulation results with the available experimental data gives opportunity to estimate the accuracy of the created multi-scale model.

中文翻译：

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钼塑性的两尺度模拟：原子模拟和位错动力学与非线性迁移率函数的结合

摘要 我们提出了钼塑性变形的多尺度模拟。螺型位错和刃型位错的温度相关迁移率函数是通过分子动力学模拟计算的，具有两种不同的原子间势。在施加的剪切应力下对螺旋位错运动的模拟表明，该过程可以在两种不同的状态下进行：通过热激活运动和非热运动。因此，位错速度以一种非平凡的方式取决于剪切应力。我们在计算迁移函数及其在位错动力学 (DD) 模型中的实现过程中考虑了这一事实。这种模型允许我们在考虑温度对位错迁移率的影响的情况下模拟塑性变形。在这里，我们讨论 DD 预测的变化取决于从原子模拟获得的输入参数。作为主要结果，我们报告了在不同温度、应变速率和位错密度下为单晶钼计算的屈服应力。对模拟结果与可用实验数据进行深入讨论的比较为估计创建的多尺度模型的准确性提供了机会。