多曲率截面TC4钛合金超塑性胀形工艺

Superplastic bulging process of TC4 titanium alloy with multi-curvatures section

为研究多曲率截面TC4钛合金超塑性胀形过程中成形气压加载速度对零件成形效果的影响,利用MARC有限元软件对TC4钛合金板材在应变速率为2×10^(-3)s^(-1)条件下进行了超塑性胀形模拟,获得了气压-时间加载曲线。基于该曲线设计了3种不同成形气压加载速度曲线,并分别进行了超塑性胀形试验。试验结果表明,在3种不同成形气压加载速度条件下,气压加载速度越慢,零件成形效果越好。零件各个位置壁厚变化均匀且实际壁厚减薄趋势与模拟得到的壁厚减薄趋势大致相符,零件实际最大壁厚减薄率约为25%,满足零件使用要求。成形后的零件各变形区域的晶粒形状变化不大且均为等轴晶粒,晶粒尺寸随着板材形变量的增大而减小。

To study the influence of forming pressure loading velocity on forming effects in superplastic bulging process of TC4 aluminum alloy with multi-curvatures section,the superplastic bulging simulation of TC4 aluminum alloy sheet with the strain rate of 2×10^(-3)s^(-1)was carried out using MARC finite element software,and the pressure-time loading curve was obtained.Based on the curve,three different forming pressure loading velocity curves were designed and superplastic bulging tests were performed,respectively.The test results show that under the conditions of three different forming pressure loading velocities,the slower the pressure loading velocity is,the better the forming effect of the parts is.The wall thickness variation in each position of the part is uniform and the actural wall thickness reduction trend is consistent with the wall thickness reduction trend obtained by simulation,the actural maximum wall thickness reduction rate is about 25%,which meets the parts operating requirement.The change of grain shape in each zone of the formed parts is not distinct and the grains are equiaxed,and the grain size decreases with the increase of the sheet deformation amount.