Additive manufacturing of Al18Co30Cr10Fe10Ni32 high entropy alloy by gas atomization and laser powder bed fusion

Abstract

Dense and crack-free, novel, eutectic Al18Co30Cr10Fe10Ni32 high entropy alloy was additively fabricated by the laser powder bed fusion (LPBF) using gas atomized alloy powders. LPBF parametric optimization was performed as a function of laser power (200–350 W) and scan speed (300–1800 mm/s). Microstructure of the densest sample exhibited a unique trimodal microstructure, along the build direction, consisting of fine cellular, coarse cellular, and conventional lamellar eutectic structures of face centered cubic (FCC) and body centered cubic (BCC) phases. This microstructural variation was significantly different from the starting powder microstructure, and the melt-pool microstructure observed during single laser scanning of arc-melted bulk alloy. The as-built alloy exhibited the outstanding tensile properties of yield strength, σY = 1.06 GPa, tensile strength, σUTS = 1.37 GPa, and elongation at failure, El = 21.3%.