背压对AA5083铝合金超塑成型的影响

Effect of Back-Pressure on Superplastic Forming for AA5083 Aluminum Alloy

采用有限元软件Marc模拟超塑成型过程,预测成型零件的壁厚和成型结果,并获得优化的压力-时间加载曲线;再分别以0和3.5 MPa的背压对AA5083铝合金进行锥形件的超塑成型和背压成型试验。结果表明:随着应变的增大,壁厚变得不均匀,合金板料变薄最严重的部位在成型件锥顶处,成型试验后零件壁厚与预测结果吻合较好;应变越大,合金成型件中空洞体积分数越大;增加背压可以有效抑制空洞的形成,显著提高材料的成型极限。

Finite element software Marc was used to simulat the superplastic forming （SPF） process, predict the thickness of the forming parts and forming results and get the optimized curves of pressure-time loading curves. The SPF and back-pressure forming tests for the AA5083 aluminum alloy were performed at the back-pressure of 0 and 3.5 MPa. The results show that the larger the strain, the less uniform the thickness. The thinnest position of the plates was located at the cone roof of the forming part and the predicted thickness was good agreement with the experimental result. The larger the strain, the larger the volume fraction of cavities. The increase of the back- pressure could effectively inhibit the cavity formation and improve the forming limit significantly.