Abstract
TC18 titanium alloy was subjected to hot rolling at 840 ℃,followed by annealing experiments at 830,860,and 890 ℃ for different time lengths.The effects of annealing temperature and time on phase transformation and static recrystallization(SRX)behavior,as well as the interaction between phase trans-formation and SRX,were studied.The results showed that at the low annealing temperature of 830 ℃,the microstructure underwent β → α phase transformation and α grain growth with the increase of annealing time,and the SRX of β phase proceeded through subgrain nucleation mechanism induced byα particles.At the middle annealing temperature(860 ℃),the α → β phase transformation occurred before the SRX of β phase,and the SRX of β phase was dominated by the grain boundary(GB)bulge mechanism.Meanwhile,the reduction of α phase content accelerated the SRX rate and grain growth.As the annealing temperature(890 ℃)exceeded the β transus temperature,the α phase completely trans-formed to the β phase,and the SRX of the β phase proceeded with a very fast grain growth rate.In addition,the interaction between phase transformation and SRX affected the distribution of α particles.The large-sized α particles(830 ℃)were located at the triple GB junction and hindered the SRX β grain growth,while smaller α particles(860 ℃)were bypassed by β GB and dispersed within the SRX β grains.
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