A high-strength and ductile titanium alloy fabricated by metal injection molding

This study presents a high-strength and ductile titanium (Ti) alloy fabricated by introducing 0.5 wt% graphite into a Ti-Al-Mo-V-Cr-based alloy (termed as ‘A-0.5C’) using metal injection molding (MIM), with the comparison of non-graphite doped alloy (termed as ‘A’). The microstructural analysis shows numerous TiC precipitates distributed along grain boundaries, forming a coherent interface with the Ti matrix. Furthermore, carbon doping promotes a multi-stage densification mechanism, efficiently reducing residual porosity and further enhancing final ductility. The A-0.5C specimen exhibited an ultimate tensile strength of 1277.8 ± 5.4 MPa and a total elongation of 11.7 ± 0.3 %. The strengthening effects arise from solid solution, grain refinement, and secondary phase. In addition, the coherent interface between the TiC precipitate and matrix helps to relieve stress concentration, and resist crack initiation and propagation, benefiting ductility. Our developed Ti alloy fabricated by MIM surpasses the strength of 1100 MPa, achieving the high-strength level while maintaining excellent ductility. This study paves the way for high-performance Ti alloys in advanced engineering applications.