Development of oxidation-resistant L12-strengthened medium to high entropy alloys for additive manufacturing

Abstract

This study investigates the oxidation kinetics of a newly designed L12-strengthened medium entropy alloy (MEA) and high entropy alloy (HEA) produced by additive manufacturing and compares them with commercially available IN718 and MAR-M247 alloys. Isothermal oxidation tests at 900 °C to 1100 °C, a cyclic oxidation test at 1100 °C, and subsequent microstructural analysis revealed that the designed MEA and HEA exhibited excellent oxidation resistance with much lower weight changes than IN718 without any crack-induced oxides as observed in MAR-M247. The superior oxidation resistance of the designed alloys is attributed to the preparations of crack-free samples that form a protective and uniform α-Al2O3 layer. In the present work, the design for alumina-forming L12-strengthened HEAs with an optimal combination of oxidation resistance and 3D printability is also discussed.