Abstract The effect of precipitates on the strength of Mg alloy, WE43, has been investigated. Transmission electron microscopy (TEM) provides unequivocal evidence that the ordered prismatic plate-shaped β′ precipitates are sheared by basal slip of dislocations. However, non-basal and pyramidal dislocations are unable to shear the precipitates, and instead bow around them during plastic deformation. In the latter case the Orowan looping model accurately predicts precipitate hardening. For the case of the shearable particles, it is proposed that order strengthening is the dominant mechanism by which the β′ phase provides strengthening to the basal slip system, and a new model quantifying this effect is developed. Using this model in conjunction with TEM observations and elastoplastic self-consistent polycrystal modeling, the anti-phase boundary energy (APB) of the precipitates is estimated to be 210 mJ/m2. The present work has significant implications for Mg alloy design strategies, and emphasizes the importance of considering both precipitate shearing and Orowan looping of precipitates. Finally, it suggests the value of making first-principles predictions of APB energies (γ-surfaces) of the candidate strengthening phases.

中文翻译：

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镁合金 WE43 中位错剪切和析出环化的滑移模式依赖性

摘要 研究了析出物对 WE43 镁合金强度的影响。透射电子显微镜 (TEM) 提供了明确的证据，表明有序棱柱状板状 β' 沉淀物被位错的基底滑移剪切。然而，非基底位错和金字塔位错无法剪切沉淀物，而是在塑性变形过程中围绕它们弯曲。在后一种情况下，Orowan 循环模型准确预测沉淀硬化。对于可剪切颗粒的情况，提出了有序强化是 β' 相为基底滑移系统提供强化的主要机制，并开发了一种量化这种效应的新模型。将此模型与 TEM 观察和弹塑性自洽多晶建模结合使用，析出物的反相界能 (APB) 估计为 210 mJ/m2。目前的工作对镁合金设计策略具有重要意义，并强调了考虑沉淀剪切和沉淀的 Orowan 环的重要性。最后，它提出了对候选强化相的 APB 能量（γ 表面）进行第一性原理预测的价值。