Finite Element Simulation of Superplastic Forming of TC4 Titanium Alloy Hemispherical Part

Finite element model for superplastic forming of TC4 titanium alloy hemispherical part was established, and the effect of direct bulging and bidirectional bulging forming on the wall thickness of the hemispherical part under constant temperature was studied. The superplastic forming process of the hemispherical part under non-uniform temperature field was simulated based on the temperature field modified Backofen constitutive equation, and the wall thickness distribution was analyzed. The TC4 titanium alloy hemispherical part was producted, and the wall thickness was measured to verity the simulation. The results show that the bidirectional bulging forming process was beneficial to the uniform distribution of thickness of the hemispherical part and reduced the maximum thinning rate of thickness of the part. The uniformity degree of thickness of the hemispherical part under non-uniform temperature field was lower than that under constant temperature. Compared with that at constant temperature, the wall thickness simulation of the hemispherical part under non-uniform temperature field was closer to the measured results; the average relative error was 4.7%, and the relative error of the wall thickness at the center point of the hemispherical part was only 6.1%.