论文标题
多主元素合金中的空置扩散：化学障碍在有序晶格中的作用
Vacancy diffusion in multi-principal element alloys: the role of chemical disorder in the ordered lattice
论文作者
论文摘要
多质元素合金（MPEAS）的许多声称的优点，例如腐蚀，高温氧化和耐辐射耐药性，对空位扩散率高度敏感。同样，溶质交叉扩散受空缺扩散的控制 - 通常不清楚MPEA是真正稳定的还是通过缓慢的互嵌液有效稳定的。这些合金提供的大量构图空间使得对所需特性进行优化是艰巨的任务。理论和计算工具是指导合金开发的必要条件。为了扩散，这样的工具既取决于对给定合金内空位迁移壁垒的知识，又取决于对这些障碍如何影响空缺扩散率的理解。我们提出了在坚固的能量景观中的空置扩散理论，并与MPEA空位扩散的动力学蒙特卡洛模拟配对。屏障能量统计数据是通过均值圆锥形合金中的弹性频带计算得出的。理论和模拟表明，固定液分MPEA中的空缺扩散不一定迟钝，而是可能会调节的，并且陷阱模型是锥形锥形中缓慢扩散的解释不足。这些结果还表明，任何努力代表与扩散相关的现象的模型都必须解释能量格局的全部性质，而不仅仅是迁移障碍。
Many of the purported virtues of Multi-Principal Element Alloys (MPEAs), such as corrosion, high-temperature oxidation and irradiation resistance, are highly sensitive to vacancy diffusivity. Similarly, solute interdiffusion is governed by vacancy diffusion -- it is often unclear whether MPEAs are truly stable, or effectively stabilized by slow interdiffusion. The considerable composition space afforded to these alloys makes optimizing for desired properties a daunting task; theoretical and computational tools are necessary to guide alloy development. For diffusion, such tools depend on both a knowledge of the vacancy migration barriers within a given alloy and an understanding of how these barriers influence vacancy diffusivity. We present a generalized theory of vacancy diffusion in rugged energy landscapes, paired with Kinetic Monte Carlo simulations of MPEA vacancy diffusion. The barrier energy statistics are informed by nudged elastic band calculations in the equiatomic CoNiCrFeMn alloy. Theory and simulations show that vacancy diffusion in solid-solution MPEAs is not necessarily sluggish, but can potentially be tuned, and that trap models are an insufficient explanation for sluggish diffusion in the CoNiCrFeMn HEA. These results also show that any model that endeavors to faithfully represent diffusion-related phenomena must account for the full nature of the energy landscape, not just the migration barriers.
