Effect of cooling rate on microstructure evolution during α/β heat treatment of TA15 titanium alloy

► The volume fraction of primary α phase of TA15 alloy is sensitive to cooling rate. ► The growth rate of primary α phase increases with the increase of cooling rate. ► Under similar conditions, TA15 alloy produces less primary α phase than Ti-6Al-4V. ► The particle size distribution becomes more uniform with decreasing cooling rate.