The advent of multiprincipal element alloys (MPEAs) has sparked significant interest in physical metallurgy. These alloys, distinguished by their high configurational entropy aimed at minimizing free energy, have raised intriguing questions regarding the interplay of chemical disorder and chemical short-range order (CSRO) in kinetics of MPEAs. Particularly, the widely assumed phenomenon of sluggish diffusion has come under scrutiny. Here we employ atomistic simulations to quantitatively evaluate the impact of CSRO on diffusion in a representative medium-entropy alloy. We introduce a physical order parameter to establish a quantitative correlation between CSRO and diffusivity. Surprisingly, our simulations suggest that CSRO, rather than chemical disorder, serves to suppress and localize defect diffusion. The observed link between diffusion activation energy and CSRO provides a rationale for the observed deceleration in diffusion due to chemical ordering. A linear relationship between diffusion activation energy and activation entropy is unveiled, aligning with the Meyer-Neldel rule, and replicating experimental results. These insights help clarify the intricate role of chemical disorder in plastic deformation of chemically disordered materials.

中文翻译：

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化学无序在减缓复杂浓缩合金扩散中的作用

多主元合金（MPEA）的出现引起了人们对物理冶金学的极大兴趣。这些合金以其高构型熵而著称，旨在最大限度地减少自由能，引发了有关 MPEA 动力学中化学无序和化学短程有序 (CSRO) 相互作用的有趣问题。特别是，人们普遍认为的扩散缓慢现象受到了密切关注。在这里，我们采用原子模拟来定量评估 CSRO 对代表性中熵合金中扩散的影响。我们引入物理序参数来建立 CSRO 和扩散率之间的定量相关性。令人惊讶的是，我们的模拟表明 CSRO，而不是化学无序，可以抑制和定位缺陷扩散。观察到的扩散活化能和 CSRO 之间的联系为观察到的由于化学排序而导致的扩散减速提供了理论依据。揭示了扩散活化能和活化熵之间的线性关系，与迈耶-内德尔规则一致，并复制了实验结果。这些见解有助于阐明化学无序在化学无序材料塑性变形中的复杂作用。