Multi-principal element alloys (MPEAs) exhibit outstanding mechanical properties because the core effect of severe atomic lattice distortion is distinctly different from that of traditional alloys. However, at the mesoscopic scale the underlying physics for the abundant dislocation activities responsible for strength-ductility synergy has not been uncovered. While the Eshelby mean-field approaches become insufficient to tackle yielding and plasticity in severely distorted crystalline solids, here we develop a three-dimensional discrete dislocation dynamics simulation approach by taking into account the experimentally measured lattice strain field from a model FeCoCrNiMn MPEA to explore the heterogeneous strain-induced strengthening mechanisms. Our results reveal that the heterogeneous lattice strain causes unusual dislocation behaviors (i.e., multiple kinks/jogs and bidirectional cross slips), resulting in the strengthening mechanisms that underpin the strength-ductility synergy. The outcome of our research sheds important insights into the design of strong yet ductile distorted crystalline solids, such as high-entropy alloys and high-entropy ceramics.

中文翻译：

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严重变形的结晶固体中的异质晶格应变强化。

多主元素合金 (MPEA) 表现出出色的机械性能，因为严重的原子晶格畸变的核心效应与传统合金明显不​​同。然而，在细观尺度上，尚未发现导致强度-延展性协同作用的大量位错活动的基础物理学。虽然 Eshelby 平均场方法不足以解决严重变形结晶固体的屈服和塑性问题，但在这里，我们通过考虑从模型 FeCoCrNiMn MPEA 中实验测量的晶格应变场来开发三维离散位错动力学模拟方法，以探索异质应变诱导强化机制。我们的结果表明，异质晶格应变会导致不寻常的位错行为（即，多个扭结/慢跑和双向交叉滑移），导致加强机制，支持强度-延展性协同作用。我们的研究成果为高熵合金和高熵陶瓷等坚固而易延展的扭曲结晶固体的设计提供了重要见解。