摘要
Oxidation behavior and mechanical properties of two L1 2 -strengthened high-entropy superalloys (HESAs), i.e., (Ni 2 Co 2 FeCr) 92 Ti 4 Al 4 and (Ni 2 Co 2 FeCr) 92 Nb 4 Al 4 , were systematically investigated at 700 ℃. Our results reveal that the oxidation resistance was significantly improved by the replacement of Ti with Nb with slightly optimized mechanical performance. The substitution of Ti by Nb promotes the formation of continuous Cr 2 O 3 , AlNbO 4 , and Al 2 O 3 layers, and causes a remarkable improvement in oxidation resistance, thus highlighting the greater potential of Nb-bearing HESAs to function as the elevated-temperature structural materials. The underlying mechanisms for the superior mechanical properties and oxidation resistance of the Nb-bearing HESA were carefully discussed.