Progress on rapid hot gas forming of titanium alloys: mechanism, modelling, innovations and applications

Abstract

The variable cross-section thin-walled hollow components of titanium alloys are increasingly used in the power and fuel systems of aerospace vehicles, which play an important role in reducing the weight of the structure, improving the service performance and reliability, etc. However, the formability of titanium alloys is very poor at room temperature, so it is very difficult to manufacture the complex thin-walled hollow components. Hot gas forming is an efficient strategy to form integral hollow components of titanium alloys. In this paper, some progress on this forming technology from the author’s lab is presented, which includes the deformation mechanisms, constitutive equations, process simulation, technological innovations and typical applications. Based on the research about the deformation mechanisms, the unified constitutive model was developed. Then the deformation process and microstructure evolution of gas forming could be predicted numerically. According to the difficulties of different components with different materials and geometries, new forming process with non-uniform temperature field, new heating system and new tooling strategy were presented. The new technologies were applied to form the components with irregular cross sections and components with large expansion ratios, meeting the application demand of aerospace industry, etc.