(南昌航空大學(xué) 航空制造工程學(xué)院，南昌 330063)
摘 要: 使用Gleeble-3500型熱模擬實(shí)驗(yàn)機(jī)進(jìn)行TC4-DT鈦合金等溫恒應(yīng)變速率熱壓縮實(shí)驗(yàn)，得到不同變形條件下TC4-DT鈦合金的真應(yīng)力-真應(yīng)變曲線，分析了變形溫度與應(yīng)變速率對合金流變應(yīng)力的影響；研究了熱變形過程中TC4-DT鈦合金的微觀組織演變規(guī)律。結(jié)果表明：TC4-DT鈦合金流變應(yīng)力隨著溫度的升高和應(yīng)變速率的降低而降低，并且變形過程中伴隨著加工硬化以及動態(tài)回復(fù)與動態(tài)再結(jié)晶；不同條件下合金微觀組織演變存在較大差異，隨著變形溫度的升高，等軸α相含量不斷減少，直到幾乎消失；但微觀組織中逐漸產(chǎn)生針狀馬氏體，其含量隨著變形溫度的升高而不斷增加。此外，基于Arrhenius方程建立了TC4-DT鈦合金高溫本構(gòu)方程，同時構(gòu)建了熱加工圖，為合金熱加工提供參考。
關(guān)鍵字: TC4-DT鈦合金；熱變形；本構(gòu)方程；熱加工圖
（School of Aeronautical Manufacturing Engineering, Nanchang Hangkong University, Nanchang 330063, China）
Abstract:The isothermal constant strain rate thermal compression experiment of TC4-DT titanium alloys were carried out by Gleeble-3500 thermal simulation machine, the true stress-true strain curves of TC4-DT titanium alloys under different conditions were acquired, the effects of temperature and strain rate on the flow stress were analyzed. The microstructure evolution of TC4-DT titanium alloy during hot deformation was investigated. The results show that the flow stress of TC4-DTtitanium alloy decreases with the increase of temperature and the decrease of strain rate. The deformation process is accompanied by work hardening, dynamic recovery and dynamic recrystallization, and the microstructures of the alloys are greatly different under different conditions .With the increase of temperature, the content of equiaxed α phase decreases continuously until it almost disappears, but acicular martensite gradually appears in the microstructure, and the content of acicular maternsite increases with the increase of temperature. In addition, the high temperature constitutive equation of TC4-DT titanium alloy was established based on Arrhenius formula, and the processing map of TC4-DT titanium alloy is constructed, which provides the reference for the hot working of the alloy.
Key words: TC4 - DT titanium alloy; thermal deformation; constitutive equation; processing map
