Microstructural, mechanical and biocompatibility of Zr/Ti6Al4V alloy fabricated by selective laser melting

Titanium alloys are extensively employed as biomaterials for orthopedic and dental implants owing to their intrinsic corrosion resistance, high specific strength, and biocompatibility. In this study, Zr/Ti–6Al–4V (TC4) alloys containing up to 4 wt% Zr were fabricated via selective laser melting (SLM). Microstructural analysis revealed that Zr additions refined the microstructure and acted as a β-phase stabilizer, thereby suppressing the formation of acicular α′ martensite. Consequently, the 4 wt% Zr/TC4 alloy exhibited enhanced mechanical performance, achieving an ultimate tensile strength of 1482 MPa and a Vickers hardness of 461 HV, corresponding to increases of 55 % and 25 %, respectively, relative to TC4. Electrochemical measurements in Hanks’ solution demonstrated a positive shift in corrosion potential to −0.504 V and a reduction in corrosion current density to 3.106 × 10 −7 A cm −2 , indicating improved corrosion resistance. In vitro assays using Saos-2 cells showed >200 % higher adhesion after 24 h on the 4 wt% Zr/TC4 surface compared with TC4, evidencing enhanced cytocompatibility. Collectively, modest Zr alloying improves strength, corrosion resistance, and cytocompatibility of SLM-fabricated TC4, highlighting its potential for next-generation load-bearing biomedical implants.