In the previous papers, the sintered Ti-6Al-2Sn-4Zr-2Mo alloy compacts showed higher tensile strength than the Ti-6Al-4V alloy compacts, and the strengthening of Ti-6Al-4V alloy compacts were available by addition of fine Mo powder because of fine microstructural modification. In this study, the metal injection molding process was applied to produce the high strength α+β type titanium alloy compacts by addition of 4mass% Mo on the Ti-6Al-2Sn-4Zr-2Mo alloy compacts using Ti, Al-based pre-alloy and Mo powders. The effect of sintering conditions on the relative density, mechanical properties and oxygen content of the compacts were mainly investigated.
The relative density and tensile strength of sintered compacts were increased with increasing the sintering temperature and time, and reached up to 98% relative density and 1000MPa tensile strength by sintering at 1473K for 28.8ks. But the elongation of sintered compacts was below 10% at lower sintering temperature for short time or higher sintering temperature for long time. The microstructures of sintered compacts were consisted of acicular α and intergranular β phases, and the acicular α phase was finer than that of Ti-6Al-2Sn-4Zr-2Mo alloy compacts. Eventually, the tensile strength of Ti-6Al-2Sn-4Zr-6Mo alloy compact was reached up to 1010MPa with 14.7% of elongation by lower sintering temperature with prolonged sintering time.