(1. 南昌航空大學 航空制造工程學院，南昌 330063；
2. 中國航空發(fā)動機集團有限公司 北京航空材料研究院，北京 100095；
3. 中國航空發(fā)動機集團有限公司 先進鈦合金重點實驗室，北京 100095)
摘 要: 采用Gleeble-3500熱模擬試驗機對Ti-22Al-26Nb-2Ta-0.5Y合金進行等溫恒應變速率壓縮實驗，研究其在變形溫度900~1150 ℃、應變速率0.001~10 s-1范圍內的熱變形行為，根據DMM模型得到了3D加工圖。結果表明：流動應力隨變形溫度的升高而降低，隨應變速率的增大而增大；利用BP神經網絡建立的合金本構關系模型具有較高的精度，其相關性系數達到0.9932，平均相對誤差為7.64%，預測值偏差在15%以內的數據點達99.22%。通過對加工圖分析和微觀組織驗證得知，失穩(wěn)區(qū)域為(900~985 ℃, 0.003~0.56 s-1)、(1060~1120 ℃, 0.001~0.01 s-1)和(990~1030 ℃, 1~10 s-1)，變形機制是局部流動、絕熱剪切和裂紋；穩(wěn)定區(qū)域為(900~1000 ℃, 0.001~0.03 s-1)，變形機制是超塑性。Ti-22Al-26Nb-2Ta-0.5Y合金最佳變形工藝參數為溫度900~1000 ℃、應變速率0.001~0.03 s-1。
關鍵字: Ti-22Al-26Nb-2Ta-0.5Y合金；熱變形行為；BP神經網絡；3D加工圖
（1. School of Aeronautical Manufacturing Engineering, Nanchang Hangkong University, Nanchang 330063, China;
2. Beijing Institute of Aeronautical Materials, Aero Engine Corporation of China, Beijing 100095, China;
3. Key Laboratory of Advanced Titanium Alloys, Aero Engine Corporation of China, Beijing 100095, China）
Abstract:The isothermal constant strain rate compression test of Ti-22Al-26Nb-2Ta-0.5Y alloy was carried out by Gleeble-3500 thermomechanical simulator. The hot deformation behavior at temperature of 900-1150 ℃and strain rate of 0.001-10 s-1 was studied. The 3D processing map on the basis of DMM model was established. The results show that the flow stress decreases with the increase of deformation temperature, and increases with the increase of strain rate. The constitutive model of alloy established by BP neural network has high accuracy, whose correlation coefficient reaches 0.9932, the average relative error is 7.64%, the predictive value of deviation within 15% data points is up to 99.22%. Through processing map prediction and microstructure observation, the instability zones are (900-985 ℃, 0.003-0.56 s-1), (1060-1120 ℃, 0.001-0.01 s-1) and (990-1030 ℃, 1-10 s-1). The deformation mechanism of the instability zones is mainly flow localization, adiabatic shear and crack. The stable zone is (900-1000 ℃, 0.001-0.03 s-1). The deformation mechanism of the stable zone is mainly superplasticity. It is found that the suitable deformation parameters of Ti-22Al-26Nb-2Ta-0.5Y alloy are deformation temperature of 900-1000 ℃ and strain rate of 0.001-0.03 s-1.
Key words: Ti-22Al-26Nb-2Ta-0.5Y alloy; hot deformation behavior; BP neural network; 3D processing map
