Forming limit of Ti-4Al-2V titanium alloy plate with different microstructures at room temperature

Titanium alloys forming at room temperature has attracted increasing attention due to its low processing cost. As is known, titanium alloys with different microstructures present different forming properties. The forming limit diagram is the basis to study the material failure and forming ability in the numerical simulation of titanium alloy plate forming at room temperature. However, to obtain forming limit requires numerous experiments, which are expensive and time-consuming. In order to reduce the experimental cost and shorten the development cycle, a feasible progression-dependent method based on the finite element (FE) simulation was adopted to determine the process from localized necking to fracture, which was also used to predict the forming limit diagrams of TA17 titanium alloy plate with different microstructures. The FE simulation results of the forming limit were compared with those of uniaxial tensile test, punch bulging test, and round cup drawing test. The results verified the correctness of the FE simulation results. Moreover, the forming limits of three TA17 titanium alloys with different microstructures were compared, and the effect of microstructure on their forming limits at room temperature was analyzed. Results show that the TA17 titanium alloy with the equiaxed microstructure provided the best performance on the forming limit, which was also supported by the fractographs of the samples. This work sheds light on the research on the forming properties of titanium alloys microstructures produced by different heat treatment processes, and establishes a foundation for the subsequent work on the stamping of TA17 titanium alloys. © 2020, Editorial Board of Journal of Harbin Institute of Technology. All right reserved.