(1. 南昌航空大学 航空制造工程学院，南昌 330063；
2. 中国航空发动机集团有限公司 北京航空材料研究院，北京 100095；
3. 中国航空发动机集团有限公司 先进钛合金重点实验室，北京 100095)
摘 要: 采用Gleeble-3500热模拟试验机对Ti-22Al-26Nb-2Ta-0.5Y合金进行等温恒应变速率压缩实验，研究其在变形温度900~1150 ℃、应变速率0.001~10 s-1范围内的热变形行为，根据DMM模型得到了3D加工图。结果表明：流动应力随变形温度的升高而降低，随应变速率的增大而增大；利用BP神经网络建立的合金本构关系模型具有较高的精度，其相关性系数达到0.9932，平均相对误差为7.64%，预测值偏差在15%以内的数据点达99.22%。通过对加工图分析和微观组织验证得知，失稳区域为(900~985 ℃, 0.003~0.56 s-1)、(1060~1120 ℃, 0.001~0.01 s-1)和(990~1030 ℃, 1~10 s-1)，变形机制是局部流动、绝热剪切和裂纹；稳定区域为(900~1000 ℃, 0.001~0.03 s-1)，变形机制是超塑性。Ti-22Al-26Nb-2Ta-0.5Y合金最佳变形工艺参数为温度900~1000 ℃、应变速率0.001~0.03 s-1。
关键字: Ti-22Al-26Nb-2Ta-0.5Y合金；热变形行为；BP神经网络；3D加工图
（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
