High strain rate compressive behaviour of 6000-series aluminium alloy sheet under SHPB impact loading

High velocity forming technologies are widely used in manufacturing industries to improve the formability of the aluminum alloy sheets. In order to better control the high velocity forming technologies through numerical simulation, the dynamic compression properties of the thin 6000-series aluminum alloy sheet were investigated by SHPB experiments. The influence of strain rate on the mechanical properties is analyzed in detail. Results show the elastic modulus is independent of the strain rate. However, under high strain rate condition, the yield stress, ultimate compression strength and ductility enhance with the increased high strain rate. So this 6000-series aluminum alloy sheet has significant strain rate sensitivity. As a reference, the quasi-static uniaxial tension test is also carried out and the uniaxial compressive stress-strain data in the literature is also listed. However, it is found the quasi-static uniaxial tensile yield stress is larger than the uniaxial compressive yield stress, and the quasi-static uniaxial compressive yield stress is lower than that under dynamic compressive condition. Results prove the aluminum alloy has obvious tension-compression anisotropy. For the high velocity forming technologies that take stretching as the main deformation mode, the dynamic tensile behaviour, instead of the dynamic compressive behaviour, should be used for accurate simulation.