Effect of solution treatment time on plasticity and ductile fracture of 7075 aluminum alloy sheet in hot stamping process

The effect of solution treatment time on the post-formed plasticity and ductile fracture of 7075 aluminum alloy in the hot stamping process was studied. Tensile tests were conducted on the specimens subjected to the hot stamping process with different solution treatment time. The digital image correlation (DIC) analysis was used to obtain the strain of the specimen. Based on the experiments and modeling, the Yld2000-3d yield criterion and the DF2014 ductile fracture criterion were calibrated and used to characterize the anisotropy and fracture behavior of the metal, respectively. Furthermore, the microstructure of specimens was studied. The experimental and simulation results indicate that the 7075 aluminum alloy retains distinct anisotropy after the hot stamping process, and there is no obvious effect of extending the solution treatment time on the material anisotropy. However, it is found that a longer solution treatment time can increase the fracture strain of the aluminum alloy during the hot stamping process, which may be related to the decrease of the second-phase particles size.