Slip mode dependency of dislocation shearing and looping of precipitates in Mg alloy WE43
Slip mode dependency of dislocation shearing and looping of precipitates in Mg alloy WE43
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DOI：
10.1016/j.actamat.2017.12.043
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发表时间：
2018-03-01
期刊：
影响因子：
9.4
通讯作者：
Agnew, S. R.
中科院分区：
文献类型：
--
作者：
Bhattacharyya, J. J.;Wang, F.;Agnew, S. R.
研究了析出相对WE 43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，有序的棱柱板状β '沉淀物被位错的基底滑移剪切。然而，非基底位错和锥体位错不能剪切沉淀物，而是在塑性变形期间围绕它们弯曲。在后一种情况下，Orowan循环模型准确地预测沉淀硬化。对于可剪切颗粒的情况，提出有序强化是β '相对基底滑移系提供强化的主要机制，并提出了一个新的模型来量化这种效果。使用该模型结合TEM观察和弹塑性自洽多晶建模，沉淀物的反相边界能（APB）估计为210 mJ/m（2）。目前的工作有显着的影响，镁合金的设计策略，并强调考虑沉淀剪切和Orowan循环的沉淀物的重要性。最后，它建议的价值，使第一性原理预测的APB能量（伽玛表面）的候选强化阶段。(C)2017 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
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 beta' 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 beta' 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/m(2). 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 (gamma-surfaces) of the candidate strengthening phases. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.