(中南大學(xué) 粉末冶金國家重點(diǎn)實(shí)驗(yàn)室，長沙 410083)
摘 要: 通過連續(xù)升溫?zé)崤蛎浄ǚ治鯰i55531(Ti-5Mo-5Cr-5V-3Al-1Zr)合金在連續(xù)升溫過程中的熱膨脹行為、物相組成和顯微組織，繪制熱膨脹微分曲線。結(jié)果發(fā)現(xiàn)：隨著升溫速率的增加，相變溫度逐漸升高。其中，在1 ℃/min的升溫速率下不同溫度區(qū)間內(nèi)的相變行為如下：低于192 ℃時(shí)，發(fā)生ωath→β轉(zhuǎn)變；192~347 ℃時(shí)，發(fā)生β→ωiso轉(zhuǎn)變；347~376 ℃時(shí)，發(fā)生ωiso→α+β、β→α轉(zhuǎn)變；409~648 ℃時(shí)，發(fā)生β→α轉(zhuǎn)變；648~831 ℃時(shí)，發(fā)生α→β轉(zhuǎn)變；831 ℃時(shí)，轉(zhuǎn)變?yōu)槿陆M織。計(jì)算得到α→β轉(zhuǎn)變熱激活能為188.04 kJ/mol。
關(guān)鍵字: Ti55531鈦合金；熱膨脹；相變序列；熱激活能
（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
