Subtle change in the work hardening behavior of fcc materials processed by selective laser melting

Single face centered cubic (fcc) AISI (American Iron and Steel Institute)-316L stainless steel and CoCrFeMnNi-high entropy alloy (HEA) were successfully fabricated using selective laser melting (SLM). Both the SLM processed alloys reveal the presence of hierarchical microstructure (presence of columnar grains, and cellular substructures). Also, the microhardness and tensile properties of AISI 316L stainless steel and CoCrFeMnNi-HEA are similar, where the microhardness varies between 240 and 270 HV0.5 and the yield strength and ultimate tensile strength are observed to be around similar to 500 MPa and similar to 600 MPa respectively. The aim of this research is to study the influence of rapid work hardening vs steady state working hardening in two materials of same crystal structure. Accordingly, CoCrFeMnNi-HEA exhibits higher work hardening rate at lower strains (<5% true strain); however, it lacks its work hardening stability at higher strain. While in case of AISI 316L stainless steel, even though, it shows lower work hardening at initial strain, it withstands at higher strain (high ductility) due to stable work hardening ability by twin mediated plasticity during plastic deformation.