CoCrFeMnNiAl高熵合金氧化皮附着力的高通量热力学筛选
High-throughput thermodynamic screening of oxide-scale adhesion across the CoCrFeMnNiAl high-entropy alloys
- University of Manitoba（曼尼托巴大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究利用宏观原子模型结合McLean和Guttmann模型，高通量筛选CoCrFeMnNiAl高熵合金中五种反应性元素对氧化皮附着力的影响，发现氧化物依赖的排序反转，并确定Co16Cr16Fe16Ni16Al35为最佳抗硫成分。
AI中文摘要：
反应性元素（RE）添加的一个显著优势是高温氧化过程中氧化皮保持性的巨大改善。在高熵合金中选择最佳RE掺杂剂仍然依赖经验，因为所需成分分辨率下的相关热力学景观无法通过第一性原理获得。这里我们应用宏观原子模型，结合McLean等温线和Guttmann模型，在Cr2O3和Al2O3界面筛选九个CoCrFeMnNiAl子家族的附着力，对五种RE（Hf、Y、Zr、La、Ti）的偏析、附着力增强和硫置换进行排序。筛选揭示了氧化物依赖的排序反转，Hf在Cr2O3界面占主导，而La在Al2O3界面占主导，这由RE-O和RE-基体相互作用焓之间的相互作用驱动。含Mn合金表现出固有的抗硫性，与其实验观察到的氧化特性一致。硫免疫相图确定了Al+Mn≥25 at%的成分对S诱导的附着力损失具有热力学免疫性。所有交叉浓度都归结为一个由偏析焓差控制的通用指数，提供了一个可转移的设计规则。逆向设计确定Co16Cr16Fe16Ni16Al35为最佳S免疫成分，其W_sep = 5.95 J/m^2，无需RE掺杂。
英文摘要：
One significant benefit of reactive element (RE) additions is the colossal improvement in oxide-scale retention during high-temperature oxidation. Selecting optimal RE dopants in high-entropy alloys remains empirical because the relevant thermodynamic landscape is inaccessible to first-principles at the required compositional resolution. Here we apply the macroscopic atom model, coupled with McLean isotherm and Guttmann models, to screen adhesion across nine CoCrFeMnNiAl sub-families at \ce{Cr2O3} and \ce{Al2O3} interfaces, ranking five REs (Hf, Y, Zr, La, Ti) for segregation, adhesion enhancement, and sulfur displacement. The screening reveals an oxide-dependent ranking inversion, with Hf dominating at \ce{Cr2O3} and La dominating at \ce{Al2O3}, driven by the interplay between RE--O and RE--matrix interaction enthalpies. Mn-containing alloys exhibit intrinsic sulfur resistance, consistent with their experimentally observed oxidation characteristics. A sulfur immunity phase diagram identifies compositions with Al~+~Mn~$\gtrsim$~25~at\% as thermodynamically immune to S-induced adhesion loss. All crossover concentrations collapse onto a universal exponential governed by the segregation enthalpy difference, providing a transferable design rule. Inverse design identifies \ce{Co16Cr16Fe16Ni16Al35} as the optimal S-immune composition with $W_\text{sep} = 5.95$~J/m$^2$ without RE doping.
