Aerospace Research Institute of Materials & Processing Technology，Beijing 10076
对未来运载火箭用大直径TA7ELI钛合金冷氦气瓶半球的等温冲压工艺进行了研究。采用有限元分析软件对半球等温冲压过程进行了数值模拟并开展了成形试验验证，同时结合成形前后材料显微组织、力学性能的变化，进一步分析了工艺过程对材料性能的影响规律。研究结果表明，等温冲压过程中材料的应力应变由芯部逐渐扩展到边缘，成形进程达到中后期时载荷最大，成形后半球壁厚最薄位置在球底中心边缘处。等温冲压后TA7ELI材料的组织形态和尺寸变化较小，且半球各处室温和20 K下的强度与成形前相比基本一致，成形后材料的室温延伸率均有所提高，20 K下球底处材料的延伸率有所降低但仍满足要求。
The isothermal stamping process of hemisphere shell for the large-size TA7ELI helium cylinder used for future launch vehicles had been researched in this work. The isothermal stamping process of hemisphere shell was simulated by finite element analysis software before a forming process， the influence of the process on the material properties was investigated by comparing the changes of the material microstructure and mechanical properties before and after the forming. Experimental result indicates that during isothermal stamping， the stress and strain of the material gradually extends from the core to the edge， the applied load reaches the maximum value when the forming process operates later period. Furthermore， the thinnest position of the hemisphere shell is around the center of the ball bottom. The grain morphology and size of TA7ELI material changes little after stamping， and the strength of the shell at room temperature and 20 K is almost the same as that before forming. The elongation of the shell at room temperature increases after forming， and the elongation of the bottom of the shell at 20 K decreases but still meets the requirements.