Effect of Forging Temperature and Deformation on Microstructure and Mechanical Property of Ti65 Alloy

Ti65 alloy developed independently in China is a kind of nearly α-type high-temperature titanium alloy for using at the temperature range from 600 to 650 ℃. Forging experiments with 40% and 60% deformation were conducted at T_β 40 ℃, T_β-20 ℃, and T_β +15 ℃, in order to discuss the effect of different forging temperatures and deformations on the microstructure, room temperature tensile properties, 650 ℃ tensile properties, creep and persistent performance of Ti65 alloy. The results show that, forging at T_β-40 ℃ can obtain duplex microstructure composed of primary α phase and β transition microstructure, forging at T_β-20 ℃ can obtain tri-modal microstructure composed of primary α phase, β phase, and short rod-shaped secondary α phase, forging at T_β +15 ℃ can obtain basketweave structure interwoven with striped secondary α and β phase. With the increase of deformation, the morphology and volume fraction of microstructure will change. For Ti65 alloys with three microstructure characteristics, their room temperature tensile strength and high temperature tensile strength all increase with the increase of deformation. The room temperature tensile properties and high temperature tensile properties of the duplex microstructure are superior to those of other microstructures. The creep resistance and durability of the basketweave structure are superior to other microstructures.