High Strain Rate Response of In-Situ TiB2/7055 Composite by Taylor Impact

The high strain rate deformation behavior and microstructure evolution of in situ TiB2 particle reinforced Al-Zn-Mg-Cu composite were investigated by means of Taylor impact. The dynamic tests were performed at three different impact velocities. Under three different velocities, no obvious shear failure occurred in the composite, indicating a good impact resistance. Compared to the quasi-static compression test, the dynamic yield strength increased obviously with the rise of velocity, even more than 1 GPa. The dislocation multiplication, phonon drag effect and ceramic reinforcement increased the flow stress of composite. Fine, equiaxed grain structure developed after impact, resulting from grain fragmentation or dynamic recrystallization. Finite element simulation of Taylor impact was qualitatively in agreement with the experiments, which was useful to elucidate the formation of equiaxed grain structure.