Titanium alloy sheets present inferior formability and severe springback in conventional forming processes at room temperature which greatly restrict their applications in complex-shaped components. In this paper, deformation characteristics and formability and springback behaviors of titanium alloy sheet at room temperature are systematically reviewed. Firstly, deformation characteristics of titanium alloys at room temperature are discussed, and formability improvement under high-rate forming and other methods are summarized, especially the impacting hydroforming developed by us. Then, the main advances in springback prediction and control are outlined, including the advanced constitutive models as well as the optimization of processing paths and parameters. More importantly, notable springback reduction is observed with high strain rate forming methods. Finally, potential investigation prospects for the precise forming of titanium alloy sheet in the future are suggested.

A Cu-2.35Ni-0.69Si alloy with low La content was designed in order to study the role of La addition on microstructure evolution and comprehensive properties. The results indicate that the La element demonstrates a superior ability to combine with Ni and Si elements, via the formation of La-rich primary phases. Owing to existing La-rich primary phases, restricted grain growth was observed, due to the pinning effect during solid solution treatment. It was found that the activation energy of the Ni₂Si phase precipitation decreased with the addition of La. Interestingly, the aggregation and distribution of the Ni₂Si phase, around the La-rich phase, was observed during the aging process, owing to the attraction of Ni and Si atoms by the La-rich phase during the solid solution. Moreover, the mechanical and conductivity properties of aged alloy sheets suggest that the addition of the La element showed a slight reducing effect on the hardness and electrical conductivity. The decrease in hardness was due to the weakened dispersion and strengthening effect of the Ni₂Si phase, while the decrease in electrical conductivity was due to the enhanced scattering of electrons by grain boundaries, caused by grain refinement. More notably, excellent thermal stabilities, including better softening resistance ability and microstructural stability, were detected for the low-La-alloyed Cu-Ni-Si sheet, owing to the delayed recrystallization and restricted grain growth caused by the La-rich phases.

The hot metal gas forming process can significantly improve the formability of a tube and is suitable for the manufacturing of parts with complex shapes. In this paper, a double wave tube component is studied. The effects of different temperatures (400 °C, 425 °C, 450 °C and 475 °C) and different pressures (1 MPa, 1.5 MPa, 2 MPa, 2.5 MPa and 3 MPa) on the formability of 6063 aluminum alloy tubes were studied. The influence of hot metal gas forming process parameters on the microstructure was analyzed. The optimal hot metal gas forming process parameters of 6063 aluminum alloy tubes were explored. The results show that the expansion rate increases with the increase in pressure. The pressure affects the deformation of the tube, which in turn has an effect on the dynamic softening of the material. The expansion rate of parts also increases with the increase in forming temperature. The increased deformation temperature is beneficial to the dynamic recrystallization of 6063, resulting in softening of the material and enhanced deformation uniformity between grains, so that the formability of the material is improved. The optimum hot metal gas forming process parameters of 6063 aluminum alloy tubes are the temperature of 475 °C and the pressure of 2.5 MPa; the maximum expansion ratio is 41.6%.

A phenomenological model for the prediction of the forming limit curve (FLC) based on basic mechanical properties through a uniaxial tensile test can tremendously shorten the design time of the forming process and reduce the measuring costs. In this paper, a novel phenomenological model named the IMR-Baosteel model (abbreviated as the IB model) is proposed for efficient and accurate FLC prediction of hot-rolled steel sheets featuring distinct variations in thickness and mechanical properties. With a systematic test of the plane strain forming limit (FLC₀), it was found that a higher regression correlation exists between the FLC₀ and the total elongation under different sheet thicknesses. For accurate assessment of the FLC₀ from tensile properties, compared using experiments, the error of FLC₀ calculated with the proposed model is within 10%. In the IB model, the left side of FLC can be calculated using a line with a slope of −1 while the right side of the FLC is obtained via a modified Keeler model with the exponent (p) determined as 0.45 for hot-rolled steels. Complete experimental FLCs of hot-rolled steels from measurements and the literature were used to validate the reliability of the proposed model. Resultantly, the prediction of FLCs with the proposed IB model is greatly improved, and agrees much better with the experimental FLCs than the predictions of the well-known Keeler model, Arcelor model and Tata Steel model.