Overcoming strength-ductility trade-off in CoCrNi medium entropy alloy by forming fine crescent grains in laser powder-bed fusion

Abstract

This study investigated the influence of microstructure on the strengthening mechanism in CoCrNi medium entropy alloys (MEAs) fabricated by laser powder-bed fusion (L-PBF). An excellent combination of high strength and elongation was achieved in L-PBFed CoCrNi MEA. The yield strength of L-PBFed CoCrNi MEA was significantly improved because of the combined effect of grain boundary strengthening and dislocation strengthening. Due to the temperature gradient difference during L-PBF process, the crescent shape grain boundaries were evident in L-PBFed samples, which increased the mechanical properties.