Effect of Constant Temperature Treatment Near the Transition Temperature of β/α on the Micro structure of Cast Ti65 Alloy
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.
Ti65 alloylamellar microstructureconstant temperature treatmentspecial bimodal microstructure
万方数据
维普
