Damage-tolerant, corrosion-resistant high entropy alloy with high strength and ductility by laser powder bed fusion additive manufacturing

Abstract

Use of laser powder bed fusion (LPBF) additive manufacturing (AM) in structural applications requires development of a) damage-tolerant alloys (alloys that exhibit high strength and ductility despite the presence of pores and/or microcracks), and b) corrosion resistant alloys. High entropy alloys (HEAs) offer abundant alloy design space that can be used to tune deformation mechanisms and address both these challenges effectively. In line with that, transformation induced plasticity (TRIP) assisted Fe38.5Mn20Co20Cr15Si5Cu1.5 HEA (Cu-HEA) was printed with LPBF-AM. Despite the presence of 1.5 vol. % of microcracks and pores, as-built Cu-HEA exhibits tensile strength of ∼1235 MPa (highest among as-built HEAs) and ductility of ∼17.2 %, thus displaying damage-tolerant behavior. Additionally, as-built Cu-HEA exhibits a steeper polarization slope as compared to SS 17-4 PH and as-cast Cu-HEA, thus exhibiting higher passivation tendency. These findings demonstrate an effective strategy for developing damage-tolerant anticorrosive materials for LPBF-AM.