中文摘要：

为研究Ti_2AlNb合金高温超塑性自由胀形时的壁厚分布规律,对初始厚度均匀的Ti_2AlNb板材进行有限元模拟和试验研究.在胀形温度分别为910、930、950和970℃时,采用恒应变速率法对最终胀形试样的壁厚分布进行数值模拟,研究了胀形后试样的壁厚分布规律.结果表明：Ti_2AlNb板材在胀形后曲面壁厚分布不均匀,易呈现出不规则球形;胀形温度对曲面形状和壁厚具有较大的影响,变形温度对Ti_2AlNb板材超塑性自由胀形壁厚分布影响较大.在此基础上,引入温度敏感性指数n,对预测胀形壁厚的E-K模型进行修正.研究结果为Ti_2A1Nb合金在航空航天复杂薄壁结构件的超塑成形提供一定的参考依据.

英文摘要：

In order to research the thickness distribution laws of Ti2 A1Nb alloy when it is deformed with the superplastic free bulging in high temperature, the Ti2A1Nb sheet with an uniform initial thickness, has been studied by the finite element simulation and experiment in this paper. Laws of the limit bulged samples are experimented in the 910 ℃, 930℃, 950 ℃ and 970℃. And the thickness distribution of finally bulged samples are simulated numerically with the constant strain rate. It is found that, the spherical thickness distribution is uneven after bulging spheric ; and Ti2 A1Nb sheet is bulged into irregular spherical easily; and the temperature relatively effects the al shape and the thickness as well. The temperature can affect the thickness distribution of Ti2 AINb alloy sheet formed by superplastic free bulging, based on which the temperature sensitivity index n is considered to correct the E-K model which predicts the thickness of the bulged sheet. The study provides a reference basis for the superplastic deformation of complex thin-walled structures in aerospace of Ti2AINb alloy.