(南昌航空大學(xué) 航空制造工程學(xué)院，南昌 330063)
摘 要: 采用Gleeble-3500熱模擬試驗(yàn)機(jī)對TC21鈦合金進(jìn)行了高溫?zé)釅嚎s變形試驗(yàn)。試驗(yàn)變形溫度為890~990℃，應(yīng)變速率為0.01~10 s-1。通過分析不同熱變形條件下獲得的應(yīng)力-應(yīng)變曲線和微觀組織，探究合金在高溫變形中的微觀組織演變規(guī)律。結(jié)果表明：TC21鈦合金對變形溫度和變形速率極其敏感，流變應(yīng)力隨著應(yīng)變速率的增加和溫度的降低而升高。隨著變形溫度的升高和應(yīng)變速率的降低，變形中動態(tài)回復(fù)作用增強(qiáng)，微觀組織中動態(tài)再結(jié)晶晶粒數(shù)目減少。此外，應(yīng)用線性回歸方法，建立TC21鈦合金的高溫本構(gòu)方程，經(jīng)過實(shí)驗(yàn)驗(yàn)證，該本構(gòu)模型與實(shí)驗(yàn)結(jié)果吻合較好；基于Prasad失穩(wěn)準(zhǔn)則，建立了TC21鈦合金熱加工圖，為TC21鈦合金鍛造工藝的制定提供理論依據(jù)。
關(guān)鍵字: TC21鈦合金；變形溫度；應(yīng)變速率；本構(gòu)方程；熱加工圖
（School of Aeronautical Manufacturing Engineering, Nanchang Hongkong University, Nanchang 330063, China）
Abstract:The high temperature hot compression deformation tests of TC21 titanium alloy were carried out by Gleeble-3500 thermal simulation machine. The test deformation temperature was in the range of 890-990 ℃ and the strain rate was in the range of 0.01-10 s-1. The microstructure evolution of the alloy during high temperature deformation was investigated by analyzing the stress-strain curves and the microstructure obtained under different hot deformation conditions. The results show that TC21 titanium alloy is very sensitive to deformation temperature and strain rate, and the flow stress increases with increase of strain rate and decrease of temperature. With increasing deformation temperature and decreasing strain rate, the dynamic recovery effect in the microstructure is enhanced and the number of dynamic recrystallized grains in the microstructure decreases. In addition, the high temperature constitutive equation of TC21 titanium alloy was established by the regression method. The experimental results show that the constitutive model is in good agreement with the experimental results. The processing map on the basis of Prasad instability criterion was established, which provided a theoretical basis for planning the forging process of TC21 titanium alloy.
Key words: TC21 titanium alloy; deformation temperature; strain rate; constitutive equation; processing map
