Investigation of multiscale mechanisms of dynamic deformation and fracture of 1565 aluminum alloy under plane collision and high-velocity penetration

High strength 1565 aluminum alloy was tested within impact velocity range of 250-750 m/s in two schemes of shock loading: (i) under uniaxial strain conditions and (ii) in high-velocity penetration. The combination of load regimes allows the different stages of multiscale structure formation to be retraced. The intensity of macro-meso momentum exchange is found to be responsible for both resistance to spallation and high-velocity penetration. The overall impact velocity region is found to be subdivided by three sub-regions of different mechanisms of dynamic straining and scales. The strength behavior of material differs for different regions of impact velocities. Within impact velocity regions where the resistance to penetration increases, the spall strength decreases. The transition from one scale level to another is shown to be realized through the excitation of velocity oscillations at the mesoscale.