Effect of CaB6 addition on the microstructure and mechanical properties of Ti–24Nb–4Zr-2.5Mn alloys fabricated by spark plasma sintering

Balancing the strength, ductility and Elastic modulus of β-Ti alloys is still a great challenge for medical implantation, extremely limiting its further applications. Herein, we prepared a fine-grain β-type Ti-24Nb-4Zr-2.5Mn alloy with high performance by adding CaB6 deoxidizer via mechanical alloying and spark plasma sintering. The effects of CaB6 addition on the microstructure and mechanical properties were systematically investigated, and the results show that adding a trace amount of CaB6 will form in-situ nano-sized CaTiO3 particles and micro-sized (Ti,Nb)B2 solid solution whiskers, which can significantly refine the grain size and inhibit the grain boundary movement and dislocation motion, thus improving the comprehensive mechanical properties of Ti-24Nb-4Zr-2.5Mn alloys. A trace addition of 0.1 wt.% CaB6, the Ti-24Nb-4Zr-2.5Mn alloy exhibits an excellent combination of high strength of ∼971 MPa, good ductility of ∼17.8% and low elastic modulus of ∼79.1 GPa. This work may provide a new methodology to prepare high-performance biomedical Ti alloys.