In order to help comprehend the influence of short-range order (SRO) structures on both the mechanical property and microstructural evolution of single crystalline medium entropy alloys (MEAs), a physical mechanism-based crystal plasticity theory is developed in this work, which covers the deformation mechanisms of dislocation-SRO interaction, network dislocation interaction, dislocation-twin boundary interaction, twinning deformation and solid solute strengthening. Thereinto, a tensorial interaction model is proposed to effectively characterize the spatial interaction between SROs on the characteristic planes and dislocations on the slip planes, which can not only address the increase of yield stress related to the impediment of slip dislocations by SROs, but also capture the phenomenon of decreasing flow stress after the yield point due to the destruction of SRO structures. Moreover, twinning deformation has been additionally taken into account by considering the complex hardening behavior related to both co-planar and non-co-planar twinning. To help validate the proposed constitutive equations, the stress-strain relations of single crystalline CrCoNi under three different loading directions are compared between the experimental data and theoretical results. A good agreement is achieved that can help verify the proposed theoretical model and facilitate the comprehension of the underlying deformation mechanisms.

中文翻译：

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短程有序对单晶中等熵合金影响的张量相互作用模型


为了帮助理解短程有序 （SRO） 结构对单晶介质熵合金 （MEA） 的力学性能和微观结构演变的影响，本研究开发了一种基于物理机制的晶体塑性理论，该理论涵盖了位错-SRO 相互作用、网络位错相互作用、位错-孪晶边界相互作用、孪晶变形和固体溶质强化的变形机制。其中，提出了一种张量相互作用模型，以有效表征特征面上的 SRO 与滑移面上的位错之间的空间相互作用，不仅可以解决 SRO 阻碍滑移位错引起的屈服应力增加问题，还可以捕捉由于 SRO 结构的破坏而导致屈服点后流应力减小的现象。此外，通过考虑与共面和非共面孪晶相关的复杂硬化行为，还考虑了孪生变形。为了帮助验证所提出的本构方程，将实验数据和理论结果比较了单晶 CrCoNi 在 3 个不同加载方向下的应力-应变关系。该方案得到了很好的一致性，有助于验证所提出的理论模型，并有助于理解潜在的变形机制。