An atomistically informed kinetic Monte Carlo model for predicting solid solution strengthening of body-centered cubic alloys
An atomistically informed kinetic Monte Carlo model for predicting solid solution strengthening of body-centered cubic alloys
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DOI：
10.1016/j.ijplas.2019.03.004
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发表时间：
2019-11
影响因子：
9.8
通讯作者：
Shuhei Shinzato;M. Wakeda;S. Ogata
中科院分区：
文献类型：
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作者：
Shuhei Shinzato;M. Wakeda;S. Ogata
为了预测体心立方稀替位合金的固溶强化，我们开发了一个原子通知动力学蒙特卡罗（kMC）模型的螺位错运动，这是一个主要的决定因素的BCC合金的屈服强度。kMC模型只需要使用原子模拟获得的参数。在开发的kMC模型中的参数实际上确定Fe-Si稀合金使用原子推导的激活能的扭结对成核和扭结迁移，以及它们的应力依赖性。采用基于第一性原理密度泛函理论的原子间相互作用势的轻推弹性带方法计算了活化能。最后，临界解析剪切应力（CRSS），激活体积的位错滑移，以及它们的温度和溶质浓度的依赖性直接获得的二维kMC位错滑移模拟。我们的kMC模型定性地再现了实验观察到的温度和浓度依赖性的CRSS的趋势，因此，它可以自然地描述固溶强化，软化没有任何经验信息。此外，还讨论了二维模型的局限性，包括单滑移和缺乏非Schmid效应，这导致定量的差异与实验CRSS。
In order to predict solid solution strengthening in body-centered cubic dilute substitutional alloys, we developed an atomistically informed kinetic Monte Carlo (kMC) model for screw dislocation motion, which is a major determinant of the yield strength of the BCC alloys. The kMC model only requires parameters obtainable using atomic simulations. The parameters in the developed kMC model were actually determined for Fe–Si dilute alloys using atomistically derived activation energies of kink-pair nucleation and kink migration as well as their stress dependencies. The activation energies were computed using the nudged elastic band method with developed interatomic potentials based on first-principles density functional theory. Eventually, the critical resolved shear stress (CRSS), activation volume of the dislocation glide, and their temperature and solute concentration dependencies were directly obtained by two dimensional kMC dislocation glide simulations. Our kMC model qualitatively reproduced the trends of experimentally observed temperature and concentration dependencies of CRSS, and thus it can naturally describe solid solution strengthening, and softening without any empirical information. In addition, the limitations of the two dimensional model, including single slip and lack of non-Schmid effect, are discussed, which results in quantitative difference with the experimental CRSS.