TiCoCr‐Based Multi‐Principal Element Alloys for Biomedical Applications

Next‐generation biomedical implants require materials with excellent wear resistance, corrosion resistance, and biocompatibility. This study developed two novel multi‐principal element alloys (MPEAs) based on the TiCoCr composition (equiatomic and non‐equiatomic) with ultra‐high hardness, excellent wear resistance, corrosion stability, and biocompatibility. The as‐cast microstructures revealed a multiphase combination of Ti‐rich hexagonal closed packing (HCP), C 14 Laves, and face‐centered cubic (FCC) phases. Upon heat treatment, equiatomic (Ti 33 Co 33 Cr 33 ) MPEA developed two major body‐centered (BCC) phases and a minor HCP phase, whereas heat treatment of non‐equiatomic (Ti 50 Co 25 Cr 25 ) MPEA revealed one BCC and C 14 Laves phase. The hardness of both MPEAs was slightly reduced after heat treatment. Wear and corrosion tests conducted in Hanks' balanced salt solution (HBSS) at 37°C on heat‐treated MPEAs demonstrated improved tribological and corrosion behavior, with reduced wear and a lower coefficient of friction (COF). Electrochemical analysis indicated superior corrosion resistance, particularly for Ti 33 Co 33 Cr 33 MPEA. With respect to biocompatibility, both MPEAs demonstrated excellent cell adhesion and proliferation properties. Cell viability improved significantly, increasing from the control (100%) to ∼105% and 115% after 3 and 5 days, respectively. The combined results highlight the strong potential of these MPEAs for biomedical applications, offering a unique balance of high “density‐normalized” hardness, excellent corrosion resistance, and biological compatibility for future implant solutions.