Failure mechanism of 6252-armor steel under hypervelocity impact by 93W alloy projectile

In this study, we analyzed the fracture mechanism of the 6252-armor steel target exposed to the impact of a kinetic energy projectile made of 93W alloy. By examining the impact pressure, crater morphology, and fracture mechanism at various impact velocities, we established the relationship among these factors. As the impact velocity increased, the ratio of penetration depth to crater diameter initially increased, then stabilized, and ultimately approached 0.7 when impact pressures exceeded 49.78 GPa. For impact pressures below 70.71 GPa, macroscopic cracks were predominantly observed on the side of the crater, with no macroscopic cracks found at the bottom. However, if the pressure exceeded 70.71 GPa, the majority of macroscopic cracks occurred at the bottom of the crater. We also found a decrease in spacing between cracks or shear bands and the recrystallized grain size at the interface when the impact velocity increased. Notably, the fracture patterns demonstrated a mixture of brittle and ductile failure modes simultaneously.