Abstract Using molecular dynamics simulations, we compute the mobility of an edge dislocation in a random FCC Fe0.70Ni0.11Cr0.19 alloy over temperatures from 100 to 900 K and shear stresses up to 600 MPa. Dislocation mobilities are shown to be intrinsically length-dependent when the line length is below a minimum value, with shorter lines having a reduced mobility. We show that this minimum line length is sensitive to both temperature and stress. We develop a drag model with terms accounting for solute, phonon, and singular drag mechanisms, and fit the model to MD data in the length-independent regime. Using the drag parameters from this fit, we implement a kinetic Monte Carlo (kMC) model for dislocation motion in the solute-drag-dominated regime. The kMC model is then used to explain the length dependence of the mobility and further characterize the statistical solute environment experienced by the dislocation. Our methods and findings are readily extensible to other crystal structures (e.g., HCP, BCC).

中文翻译：

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FCC 不锈钢合金中线长相关的位错迁移率

摘要 使用分子动力学模拟，我们计算了随机 FCC Fe0.70Ni0.11Cr0.19 合金在 100 到 900 K 的温度和高达 600 MPa 的剪切应力下边缘位错的迁移率。当线长度低于最小值时，位错迁移率显示为本质上依赖于长度，较短的线具有降低的迁移率。我们表明这个最小线长度对温度和应力都很敏感。我们开发了一个阻力模型，其中包含溶质、声子和奇异阻力机制的术语，并将模型与长度无关的 MD 数据拟合。使用此拟合中的阻力参数，我们实现了动力学蒙特卡罗 (kMC) 模型，用于溶质阻力主导区域的位错运动。然后使用 kMC 模型来解释迁移率的长度依赖性，并进一步表征位错所经历的统计溶质环境。我们的方法和发现很容易扩展到其他晶体结构（例如，HCP、BCC）。