Metallurgists have long been accustomed to a trade-off between yield strength and tensile ductility. Extending previously known strain-hardening mechanisms, the emerging multi-principal-element alloys (MPEAs) offer additional help in promoting the strength-ductility synergy, towards gigapascal yield strength simultaneously with pure-metal-like tensile ductility. The highly concentrated chemical make-up in these “high-entropy” alloys (HEAs) adds, at ultrafine spatial scale from sub-nanometer to tens of nanometers, inherent chemical inhomogeneities in local composition and local chemical order (LCO). These institute a “nano-cocktail” environment that exerts extra dragging forces, rendering a much wavier motion of dislocation lines (in stick–slip mode) different from dilute solutions. The variable fault energy landscape also makes the dislocation movement sluggish, increasing their chances to hit one another and react to increase entanglement. The accumulation of dislocations (plus faults) dynamically stores obstacles against ensuing dislocation motion to sustain an adequate strain-hardening rate at high flow stresses, delaying plastic instability to enable large (uniform) elongation. The successes summarized advocate MPEAs as an effective recipe towards ultrahigh strength at little expense of tensile ductility. The insight gained also answers the question as to what new mechanical behavior the HEAs have to offer, beyond what has been well documented for traditional metals and solid solutions.

中文翻译：

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高熵合金中的化学不均匀性有助于减轻强度与延展性之间的权衡

冶金学家长期以来习惯于在屈服强度和拉伸延展性之间进行权衡。新兴的多主元合金 (MPEA) 扩展了先前已知的应变硬化机制，为促进强度-延展性协同作用提供了额外的帮助，同时实现千兆帕屈服强度和类似纯金属的拉伸延展性。这些“高熵”合金（HEA）中高度浓缩的化学成分在亚纳米到数十纳米的超精细空间尺度上增加了局部成分和局部化学顺序（LCO）中固有的化学不均匀性。这些形成了一种“纳米鸡尾酒”环境，可以施加额外的拖曳力，使位错线的运动（以粘滑模式）与稀溶液不同。多变的断层能量景观也使得位错运动迟缓，增加了它们相互碰撞并做出反应以增加纠缠的机会。位错（加上断层）的积累动态地存储了阻碍随后位错运动的障碍，以在高流动应力下维持足够的应变硬化速率，延迟塑性不稳定以实现大（均匀）伸长。这些成功将倡导者 MPEA 总结为一种在不牺牲拉伸延展性的情况下实现超高强度的有效方法。获得的见解还回答了 HEA 必须提供哪些新机械行为的问题，超出了传统金属和固体解决方案已有的详细记录。