| Abstract Scope |
Materials subjected to shock or impulsive loading can undergo spall fracture, where the rapid unloading after the shock event drives a state of high strain-rate tension. In ductile metals, damage accrues through void nucleation, growth, coalescence, and then possibly full fracture of a spall scab. Often, these shock events are not isolated and the material is expected to survive multiple events – armor, for example. Here, we systematically generate samples containing increasing amounts of incipient (i.e. before full scab formation) spall damage, characterizing the damage distribution in terms of void size, shape, and location. The samples are then subjected to a second shock event to examine how the damaged microstructures respond as a function of initial damage quantity, in particular whether the voids and cracks are merely pushed back together or if some sort of bonding process such as recrystallization is activated. |