Effects of post-aging cooling condition on structure and tensile properties of aged Ti–7.5Mo alloy

The present study investigated the effects of post-aging cooling condition on tensile properties of an aged Ti–7.5 wt% Mo alloy. Experimental results indicated that the solution-treated (ST) Ti–7.5Mo samples were comprised substantially of α″ phase, while all aged samples demonstrated the co-existence of α′ and β phases therein. The relative amount of β phase retained in the aged alloy was found sensitive to post-aging cooling condition. Water-quenched (WQ) alloy had the highest β phase content, while furnace-cooled (FC) alloy had the lowest β phase content. The Mo concentration in β phase was also sensitive to post-aging cooling condition. The average Mo concentration in β phase was found highest in FC samples and lowest in WQ samples. Compared to ST samples, all aged samples demonstrated significant increases in yield strength and modulus values, along with decreases in elongation. The effect of post-aging cooling condition on microhardness was similar to that on strength.