Effect of Mo Additions on the Physical, Mechanical and Corrosion Properties of Commercially Pure Ti Fabricated by Metal Injection Moulding

Ti-Mo alloys have received increasing attention for use in biomedical applications due to their non-toxic alloying elements, reasonable cost and suitable properties. In the present study, the effects of elemental Mo powder additions (5, 7.5, 10 and 15 wt%) on the physical, mechanical and corrosion properties in commercially pure Ti fabricated by metal injection moulding (MIM) and sintered at 1250 and 1350 °C were investigated. It was found that tensile strength increases with increasing Mo content mainly due to solid solution strengthening. However, the strain to failure of the alloys is variable and is influenced by the formation of TiC_x, the relative sintered density and by impurities depending on the Mo content and sintering temperature. From the present study the optimum alloy is Ti-7.5Mo, sintered at 1250 °C for 2 h, which offers a satisfactory balance between suitable tensile properties, high relative density (> 96.5%), and excellent corrosion resistance in an artificial saliva environment. Ti-Mo alloys can also tolerate impurities up to 0.5 wt% (Oxygen equivalent, O_eq) without any significant reduction in ductility, which is a practical advantage for manufacturing and is attractive for biomedical applications.