Characteristics of Ti-Nb-Mg alloy by powder metallurgy for biomedical applications

Abstract Different contents of Mg (3 wt% and 5 wt%) were introduced into the Ti Nb alloy to fabricate a novel Ti-Nb-Mg alloy by mechanical alloying (MA) and spark plasma sintering (SPS) from elemental powder for potential biomedical applications. The influences of ball-to-powder ratio (BPR, 10:1 and 20:1), ball-milling time and composition on the morphology evolution of MAed powder, microstructure, mechanical and biological properties of sintered Ti-35Nb-xMg samples were investigated. Compared with the MAed powder under different BPRs, the almost single phase of (Ti, Nb, Mg) bcc solid solution powder was achieved under 20:1, while the completely alloying powder cannot be achieved under 10:1. The MAed powder was subsequently sintered by SPS, all sintered alloys exhibited obvious nanopores. The alloys under 20:1 exhibited relatively uniform element distribution while obvious element segregation was found in the alloys under 10:1. The major phase in all alloys was β phase, and α-Ti and Mg phases were detected as well. For the alloys with the same composition, the alloys under 10:1 exhibited slightly higher compressive yield strength (CYS) but weaker plastic deformation capacity compared to the alloys under 20:1. The strength and fracture strain of alloys deteriorated with increasing the content of Mg from 3 wt% to 5 wt%. Moreover, all sintered alloys showed hydrophilicity, and Ti-35Nb-5Mg alloy under 20:1 exhibited good cell spread after the degradation of Mg.