Ti65 is a near α high-temperature titanium alloy independently developed in China.When used as a casting alloy,its coarse lamellar structure is difficult to control through hot isostatic pressing and heat treatment processes.This article investigated the effect of constant temperature treatment from the single-phase zone cooling to 940～1 020 ℃ of near the transition temperature of β/α on the microstructure of Ti65 alloy.The results showed that the α lamellae in Ti65 alloy was coarsened and fragmented after constant temperature treatment at 960～1 000 ℃/30 min,forming a"special bimodal microstructure"consisting of coarsened and fragmented α lamellae and fine α lamellae.The coarsening and fragmentation of α lamellae occurred during the high temperature holding period,while the fine α lamellae were formed during the subsequent cooling process.The most obvious coarsening and fragmentation of the α lamellae occurred after 960 ℃/30 min constant temperature treatment,while the morphological characteristics of the lamellae remained basically unchanged during the constant temperature treatments at 940 ℃ and 1 020 ℃,with only the thickness of the lamellae being altered.This work could provide new ideas for regulating the coarse and large layer structure of cast titanium alloys.
关键词
Ti65合金/片层组织/恒温处理/特殊双态组织
Key words
Ti65 alloy/lamellar microstructure/constant temperature treatment/special bimodal microstructure
维普
万方数据