Thermophysical properties and high temperature oxidation behavior of FeCrNiAl_0.5 multi-component alloys

This study proposed a multi-component alloy FeCrNiAl_0.5 as a candidate materials for structural applications at high temperatures. The phase structure, microstructure and chemical composition of the alloy were characterized. The results show that the alloy possesses only BCC crystal structure consisting of the ordered (Ni,Al) phase and disordered [Fe, Cr] phase. Microstructural observation combined with XRD results clearly show that the as-cast alloy exhibits a non-homogeneous microstructure with pronounced dendritic and interdendritic regions. Besides, the as-cast alloy possesses great electrical and thermal conductivity compared with other HEAs and nickel-based alloy. Moreover, the oxidation behaviors at high temperature were systematically investigated and shows a surprisingly good oxidation resistance property compared with commercially available steels and alloys. The oxidation active energy is 259.3740 kJ/mol ranging from 1173 to 1273 K. The predominant oxide is Al₂O₃, Cr₂O₃ and FeCr₂O₄ and the oxidation mechanisms were further discussed. This study suggests that FeCrNiAl_0.5 multi-component alloy exhibites great promise for high temperature structural materials.