TC4钛合金双层板结构超塑成型/扩散连接工艺

Processing of Superplastic Forming and Diffusion Bonding for Two-Sheet Structure of Ti-6A1-4V Titanium Alloy

采用先超塑成型(SPF)后扩散连接(DB)工艺对TC4钛合金双层板结构进行了加工;利用有限元软件Marc模拟了此工艺过程,获得了优化的压力-时间曲线,并预测了成型零件的壁厚和型状;并与在热成型机上的试验结果进行了对比。结果表明:最佳超塑成型参数为成型温度900℃、成型压力2.5 MPa、成型时间1 000 s;在超塑成型过程中,板料周边的厚度最薄而中间区域最厚,下面板壁厚分布比上面板均匀,成型后零件壁厚与预测结果吻合较好;最佳扩散连接参数为连接温度900℃、连接压力3 MPa、连接时间80 min;连接部位具有较高的焊合率。

The process of superplastic forming（SPF）and diffusion bonding（DB）for two-sheet structure of Ti6Al -4V titanium alloy was performed.The SPF and DB process was simulated by using finite element software Marc to optimize the curve of pressure-time and predict the thickness and shape of formed part.Then the calculated results were compared with the test results which were obtained using thermal forming machine.The results show that the optimum parameters for the SPF process were：forming temperature of 900℃,forming pressure of 2.5 MPa and forming time of 1 000 s.The thickness of surrounding region for the sheet was the thinnest while the middle region was the thickest and the thickness distribution of the upper panel was more uniform than that of the lower panel during the superplastic forming.The thickness distribution of the formed part was in good agreement with the predicted results.While the optimum parameters for the DB process were bonding temperature of 900℃, bonding pressure of 3 MPa and bonding time of 80 min.The bonding ratio at the interfaces was excellent.