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Description
Aluminum lithium alloy with many excellent properties such as low density, high elastic modulus, high specific strength has been considered as the most ideal structural material for aerospace. However, the application of Al-Li alloys is always limited in complex structural components, due to its inferior plasticity at room temperature and easy cracking during cold forming. As a novel forming technology featured with high strain rate, impact hydroforming (IHF) has the characteristics of fluid flexibility and dynamic impact wave loading. To explore the possibility of improving the formability of 2195 Al-Li alloy at room temperature, half-tube part with complex structural profile and deep cavity was formed by IHF equipment. Based on the finite element simulation, the blank dimensions of Al-Li sheet and related part forming process were designed and optimized. A two-step process was adopted for the half-tube part to meet objective requirements. With characterizing the part depth and thickness, it is found that the forming depth reaches the target height value, and the maximum thinning rate is less than 25%. The formed part has high dimensional accuracy and is completely attached to the die cavity. The elongation of the bottom area is higher than 5%, which meets the requirements of alloy for aerospace structures. It also has good surface quality without wrinkles and cracks. It indicates that the high strain rate IHF technology can effectively improve the formability of Al-Li alloy at room temperature, and has a wide application prospect.