Cryogenic and Aging Treatment Effects on the Mechanical Properties of Ti-15V-3Al-3Cr-3Sn Titanium Alloy

In this study, single and duplex aging treatment was applied to the metastable beta titanium alloy of titanium-15 vanadium-3 aluminum-3 chromium-3 tin with cryogenic treatment. The single-step aging treatment was applied for 20 h at 450 degrees C and 10 h at 550 degrees C. The cryogenic treatment was carried out at -196 degrees C for 24 h, followed by single-step or duplex aging treatment. The results obtained show that the cryogenic treatment causes the formation of martensitic alpha phases. Following the cryogenic treatment, martensitic alpha phases were observed in the sample, which was subjected to aging treatment at 450 degrees C for 20 h, whereas these phases disappeared completely in the sample treated at 550 degrees C for 10 h. Preaging treatment applied after cryogenic treatment prevented the formation of precipitate-free zones by providing a finer and uniform distribution of a phases. Cryogenic treatment followed by preaging treatment at 250 degrees C for 24 h led to the formation of dense metastable prephases. This resulted in a 10% increase in tensile strength, 4% elongation, and 5% hardness compared to preaging at 300 degrees C for 10 h after cryogenic treatment. The optimum mechanical properties in single-step sample groups were obtained in samples aged 20 h at 450 degrees C. In duplex-aged samples, optimum mechanical properties were obtained in cryogenic treatment followed by 250 degrees C/10 h + 450 degrees C/20 h duplex aging treatment.