The oxidation behavior of five different high-entropy alloys from the Al–Co–Cr–Fe–Ni metallic system, namely Al_x(CoCrFeNi)_100-x (x = 0; 3; 6; 9; 12), was studied under thermal-cycling conditions, at 1273 K in air atmosphere. The choice of selected compositions allowed for covering the chromia-to-alumina former transition, as well as the transition from the FCC single-phase solid solution structure to multiphase alloys with Al-enriched B2-structured constituent. The measurements were taken for 500 cycles (1 cycle - 1 h of heating, 20 min of cooling). The results indicate a profound influence of the thermal-cycling conditions on the oxidation products, with extremely complex scale structures and extensive internal oxidation and nitridation zones, as well as severe spallation of the oxide scale in most cases, showing the limited usefulness of these alloys for high-temperature applications at the current stage of their development.

来自 Al-Co-Cr-Fe-Ni 金属体系的五种不同高熵合金的氧化行为，即 Al _x (CoCrFeNi) _{100- x} ( x = 0; 3; 6; 9; 12)，在热循环条件下研究，在空气气氛中 1273 K。所选成分的选择允许覆盖氧化铬到氧化铝前体的转变，以及从 FCC 单相固溶体结构到具有富铝 B2 结构成分的多相合金的转变。测量进行了 500 个循环（1 个循环 - 加热 1 小时，冷却 20 分钟）。结果表明，热循环条件对氧化产物的影响深远，氧化产物具有极其复杂的氧化皮结构和广泛的内部氧化和氮化区，并且在大多数情况下氧化皮严重剥落，表明这些合金的实用性有限用于当前发展阶段的高温应用。