FCC Co

在 FCC CoCrFeNi 高熵合金中，通过实验确定了单个组分的平均有效相互扩散系数和 Ni 的示踪剂扩散系数。使用 Dayananda-Sohn 方法确定 CoCrFeNi 合金中单个元素的平均有效相互扩散系数。在 CoCrFeNi 合金中，Cr 的平均有效相互扩散系数的量级最高，而 Ni 的量级最低。使用 Belova 等人提出的新型分析方法，在不使用放射性示踪剂的情况下确定了 Ni 的示踪剂扩散系数。基于线性响应理论，结合 Boltzmann-Matano 方法和高斯分布函数。将 CoCrFeNi 中的平均有效相互扩散系数和示踪剂扩散系数与具有不同混合熵的相关高熵合金进行了比较。混合熵较高的含Al高熵合金（如Al-Co-Cr-Fe-Ni和Al-Co-Cr-Fe-Ni-Mn）中单个元素的扩散高于CoCrFeNi合金，具有相对较低的混合熵。因此，扩散不能先验认为在具有较高构型熵的合金中缓慢。此外，五元和三元含铝高熵合金的势能波动高于四元 CoCrFeNi 合金。这也表明，在势能或混合构型熵具有较高波动的合金中，组分的扩散率可能并不总是较低。

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Average effective interdiffusion coefficients of individual components and tracer diffusion coefficient of Ni were experimentally determined in FCC CoCrFeNi high entropy alloys. Average effective interdiffusion coefficients of individual elements in CoCrFeNi alloys were determined using the Dayananda-Sohn approach. Cr had the highest while Ni had the lowest magnitude of the average effective interdiffusion coefficient in the CoCrFeNi alloy. The tracer diffusion coefficient of Ni was determined without the application of radiotracers using the novel analytical method proposed by Belova et al. based on linear response theory coupled with the Boltzmann-Matano approach and Gaussian distribution function. Both average effective interdiffusion coefficients and tracer diffusion coefficients in CoCrFeNi were compared with the relevant high entropy alloys with varying entropy of mixing. The diffusion of individual elements in Al-containing high entropy alloys (e.g., Al-Co-Cr-Fe-Ni and Al-Co-Cr-Fe-Ni-Mn), with higher entropy of mixing, was higher than that in CoCrFeNi alloy, with relatively lower entropy of mixing. Therefore, diffusion cannot a priori consider to be sluggish in alloys with higher configurational entropy. Moreover, potential energy fluctuations determined in quinary and senary Al-containing high entropy alloys were higher than that in quaternary CoCrFeNi alloy. This also suggests that the diffusivity of a component may not be always lower in the alloys which possess higher fluctuations in potential energy or configurational entropy of mixing.