The mechanisms of dislocation/precipitate interactions were analyzed in an Al-Cu alloy containing a homogeneous dispersion of $\theta'$ precipitates by means of discrete dislocation dynamics simulations. The simulations were carried out within the framework of the discrete-continuous method and the precipitates were assumed to be impenetrable by dislocations. The main parameters that determine the dislocation/precipitate interactions (elastic mismatch, stress-free transformation strains, dislocation mobility and cross-slip rate) were obtained from atomistic simulations, while the size, shape, spatial distribution and volume fraction of the precipitates were obtained from transmission electron microscopy. The predictions of the critical resolved shear stress (including the contribution of solid solution) were in agreement with the experimental results obtained by means of compression tests in micropillars of the Al-Cu alloy oriented for single slip. The simulations revealed that the most important contribution to the precipitation hardening of the alloy was provided by the stress-free transformation strains followed by the solution hardening and the Orowan mechanism due to the bow-out of the dislocations around the precipitates.

中文翻译：

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铝铜合金沉淀硬化的多尺度建模：位错动力学模拟和实验验证

通过离散位错动力学模拟，在含有均匀分散的 $\theta'$ 沉淀的 Al-Cu 合金中分析了位错/沉淀相互作用的机制。模拟是在离散-连续法的框架内进行的，并且假定析出物不能被位错穿透。确定位错/沉淀相互作用的主要参数（弹性错配、无应力转变应变、位错迁移率和交叉滑移率）从原子模拟中获得，同时获得了沉淀的尺寸、形状、空间分布和体积分数来自透射电子显微镜。临界分辨剪切应力（包括固溶体的贡献）的预测与通过单次滑动取向的铝铜合金微柱压缩试验获得的实验结果一致。模拟表明，对合金沉淀硬化的最重要贡献是由无应力转变应变提供的，其次是固溶硬化和由于析出物周围位错的弓形而导致的 Orowan 机制。