(中南大学 粉末冶金国家重点实验室，长沙 410083)
摘 要: 通过连续升温热膨胀法分析Ti55531(Ti-5Mo-5Cr-5V-3Al-1Zr)合金在连续升温过程中的热膨胀行为、物相组成和显微组织，绘制热膨胀微分曲线。结果发现：随着升温速率的增加，相变温度逐渐升高。其中，在1 ℃/min的升温速率下不同温度区间内的相变行为如下：低于192 ℃时，发生ωath→β转变；192~347 ℃时，发生β→ωiso转变；347~376 ℃时，发生ωiso→α+β、β→α转变；409~648 ℃时，发生β→α转变；648~831 ℃时，发生α→β转变；831 ℃时，转变为全β组织。计算得到α→β转变热激活能为188.04 kJ/mol。
关键字: Ti55531钛合金；热膨胀；相变序列；热激活能
（State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:The dilatometry behavior, phase composition and microstructure of Ti55531(Ti-5Mo-5Cr-5V-3Al-1Zr) alloy were investigated during continuous heating process, and the derivative of dilatometric curve was thereby calculated. The results show that the phase transformation temperature increases with accelerating heating rate. Consequently, phase transformation sequence of Ti55531 alloy at heating rate of 1℃/min is confirmed as follows: temperature below 192 ℃, ωath transforms β; 192-347 ℃, β transforms ωiso; 347-376 ℃, ωiso transforms α+β and β transforms α; 409-648 ℃, β transforms α; 648-831 ℃, α transforms β; over 831 ℃, full β. The activation energy value relating to α→β transformation in Ti55531 alloy is evaluated as 188.04 kJ/mol.
Key words: Ti55531 Ti alloy; dilatometry; phase transformation sequence; activation energy
