Superior fracture resistance of additive manufactured high-entropy alloy under impact loading

Abstract

In this study, Ni40Co18Cr18Fe14Al5Ti5 high-entropy alloys (HEAs) with a near-equiaxed grain structure and cellular substructures, devoid of significant microstructural imperfections, was produced via selective laser melting (SLM). The absence of brittle precipitates or substantial processing defects, which typically serving as fracture-weakening origins, allowed for effective activation of dislocation motion, deformation twinning, and stacking faults ahead of the crack tip. These mechanisms contributed to exceptional impact toughness (∼1600 kJ/m2) and dynamic crack initiation toughness (∼1000 kJ/m2). With an impressive yield strength (∼810 MPa), our SLM-produced HEA demonstrates a unique combination of impact toughness and strength that surpasses current additively manufactured metals.