A stochastic discrete slip approach is proposed to model plastic deformation in submicron domains. The model is applied to the study of submicron pillar () compression experiments on tungsten (W), a prototypical metal for applications under extreme conditions. Slip events are geometrically resolved in the specimen and considered as eigenstrain fields producing a displacement jump across a slip plane. This novel method includes several aspects of utmost importance to small-scale plasticity, i.e. source truncation effects, surface nucleation effects, starvation effects, slip localization and an inherently stochastic response. Implementation on an FFT-spectral solver results in an efficient computational 3-D framework. Simulations of submicron W pillars () under compression show that the method is capable of capturing salient features of sub-micron scale plasticity. These include the natural competition between pre-existing dislocations and surface nucleation of new dislocations. Our results predict distinctive flow stress power-law dependence exponents as well as a size-dependence of the strain-rate sensitivity exponent. The results are thoroughly compared with experimental literature.

中文翻译：

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微塑性的随机离散滑移方法：在亚微米 W 柱中的应用

提出了一种随机离散滑移方法来模拟亚微米域的塑性变形。该模型应用于钨 (W) 的亚微米柱 () 压缩实验研究，钨是一种在极端条件下应用的典型金属。滑移事件在样本中进行几何解析，并被视为在滑移平面上产生位移跳跃的特征应变场。这种新颖的方法包括对小尺度塑性最重要的几个方面，即源截断效应、表面成核效应、饥饿效应、滑移局域化和固有的随机响应。 FFT 频谱求解器的实现产生了高效的计算 3-D 框架。对压缩下亚微米 W 柱 () 的模拟表明，该方法能够捕获亚微米级塑性的显着特征。这些包括预先存在的位错和新位错的表面成核之间的自然竞争。我们的结果预测了独特的流动应力幂律依赖性指数以及应变率敏感性指数的尺寸依赖性。结果与实验文献进行了彻底的比较。