Processing-microstructure-properties relationship of high entropy alloys fabricated by 3-dimensional printing

Abstract

Selective Electron Beam Melting (SEBM) of an equiatomic, pre-alloyed and gas atomized CoCrFeMnNi high-entropy alloy (HEA) powder was studied, with the focus put on the process window, resulting microstructure and mechanical properties. The printed samples achieved a relative density up to 98% and mainly consist of FCC phase. Columnar microstructure was observed alone the build direction and cellular sub-microstructure was observed at the cross-section. The mechanical properties characterization results showed that this HEA exhibits excellent ductility with fracture strain up to 72% along build direction. Moreover, anisotropic tensile properties were observed, this could be contributed by the long columnar grains. Thus, in the transverse direction, a sharp drop of elongation occurred.