TC6钛合金加热和冷却过程中的相转变研究

Phase Transformation in TC6 Titanium Alloy during Heating and Cooling

采用迅速水冷保留高温组织状态的方法,研究TC6钛合金在两相区加热和冷却过程中的相转变。结果表明：在加热过程中,次生α相会在700~850℃时优先固溶,初生α相在900℃时才会固溶,能谱分析结果表明,初生α相中Al元素浓度高于次生α相中Al元素浓度,因此初生α相在高温下更加稳定。在冷却过程中初生α相优先长大,而次生α相由于是通过形核长大,表现为在较低温度段才开始析出,且次生α相析出会降低初生α相的长大速度;进一步研究发现,冷却过程中次生α相析出温度会随着保温温度的降低而逐渐降低。

By means of rapid water cooling to retain the microstructure state at high temperature, the phase transformation in TC6 titanium alloy during heating and cooling processes within the two phase field was investigated. The results show that with increasing the temperature during the heating process, the secondary α dissolves within a range of temperature between 700 and 850 ℃ but the primary α dissolves at 900 ℃. The results of energy spectrum analysis show that Al element concentration in primary α is higher than that in secondary α, that is to say, primary α is more stable than secondary α at high temperature. During the cooling process, the primary α grows up preferentially at a higher temperature, while due to the formation of secondary α through nucleation and growth, it precipitates at a relatively lower temperature, and the secondary α precipitates can slow down the growth of the primary α. Furthermore, with reducing the holding temperature, the precipitation temperature of secondary α gradually decreases.