TC21合金时效过程中的相变研究

采用XRD、SEM、TEM及显微硬度测试等手段,系统研究了TC21合金固溶处理后的相变以及合金在550～850℃时а"相在时效过程中的分解机制及组织演变规律,结果表明:1000℃固溶30 min淬火后,TC21合金形成а"马氏体,且合金中存在少量β及O相(Ti2AlNb);随时效温度的升高,а"相逐步发生а"→а+а"_高→а+β_(亚稳)→а+β,а"+а'+β_(亚稳)→а+β,а"→а+β等分解过程;TC21合金的显微硬度依赖于时效温度和时效时间,时效时间延长,合金显微硬度先迅速增大,达到最大值后再逐渐减小.时效温度升高时,合金显微硬度达到最大值的时间缩短,且合金最终的显微硬度随时效温度的升高而降低.

Study on Phase Transformation of TC21 Alloy During Aging Treatment

Phase transformation during solution treatment, the decomposition mechanism and microstructure evolution of а" phase during aging treatment were systematically studied using XRD, SEM, TEM and microhardness analysis. The results show that TC21 alloy solution treated at 1000 "C for 30 min, water quenched, present an martensitic structure consisting of а" phase and little β phase, O phase (Ti2A1Nb). With the increase of aging temperature, the mechanism of the decomposition of а" phase is а" →а+а" <,高>→а+β <,亚稳 >→а+β,а"+а'+β<,亚稳>→а+β,а"→а+β. The microhardness of TC21 alloy depends on the aging temperature and aging time. The microhardness increases rapidly, reachs the maximum and gradually decreases with increasing aging time, with increasing aging temperature, the time to reach the maximum microhardness and the final microhardness of TC21 alloy decreases.