Effect of Heat Treatment on Microstructure and Tensile Property of Ti-6Al-6V-2Sn Alloy

• Main Authors: Qirui Wang, Xiaofei Lei, Ming Hu, Xin Xu, Rui Yang, Limin Dong
• Format: Article
• Language: English
• Published: MDPI AG 2021-03-01
• Series: Metals
• Subjects: Ti-6Al-6V-2Sn; titanium alloy; heat treatment; microstructure
• Online Access: https://www.mdpi.com/2075-4701/11/4/556

The microstructure and tensile properties of Ti-6Al-6V-2Sn alloy heat-treated at different solution and aging temperatures has been systematically investigated. Specimens were solution-treated at 970 °C (above the β transus) and 920 °C (below the β transus), respectively, followed by water quenching. When the alloy is quenched from 970 °C, α’ (hcp) and α˝ (orthorhombic) martensite phases co-exist in the microstructure. When it is quenched from 920 °C, α´ martensite phase does not form, while equiaxial primary α (α_p) phase and α˝ are found in the microstructure. The results also show that the strength of the alloy increases but the ductility deteriorates as the solution temperature becomes higher when the aging treatment is unchanged. This is because the volume fraction of equiaxial α_p phase is lower but the volume fraction of the acicular secondary α (α_s) phase is higher for higher solution temperature. When the alloy is aged at different temperatures after the solution treatment at 900 °C, the strength of the alloy decreases with the increase of aging temperature and the ductility shows the opposite trend as the size of the acicular α_s becomes longer and its volume fraction is lower at higher aging temperature.