Comparison of microstructure, mechanical properties and biocompatibility of CoCrFeNiMn high-entropy alloy with 316L stainless steel

The present investigation was conducted to compare CoCrFeNiMn high-entropy alloy as a new class of material with conventional 316L stainless steel. The alloys were processed by cold rolling followed by short-term annealing to achieve a single-phase microstructure with fine grains and represent high strength and ductility with an ultimate tensile stress more than 600 MPa and an elongation to failure of ∼38 % for both alloys. In vitro cell studies including osteosarcoma cell viability using MTT assay and cell attachment proposed higher proliferation together with better cell adhesion and spreading on the CoCrFeNiMn surface. The surface properties have determinant effects on the biological behavior of an implant and the present investigation revealed better surface properties of the studied high-entropy alloy compared with the 316L. Immersion test in a PBS solution indicated that the CoCrFeNiMn alloy has a lower degradation rate compared with the 316L with the average degradation rate of ∼0.02 mg.day−1. According to the present investigation, there is a potential of replacement of the 316L with the CoCrFeNiMn alloy as a implant material. It is a step forward to a fundamental understanding of this alloy as a new high-performance biomaterial.