Laser-Driven Spall in Al: Velocity Interferometry and Target Recovery

Using the HELEN laser at AWE we have done spall experiments on pure Al at strain rates between $\sim $6x10$^{5}$ and 2x10$^{6}$s$^{-1}$. A heterodyne velocity interferometer (Het-V) recorded rear-surface velocity profiles and the majority of targets were recovered. We have compared the behaviour of polycrystalline and single-crystal Al of four different crystal orientations. The results allow the correlation of pre-shot target structure -- determined by electron backscatter diffraction -- with the velocity profiles and recovered-target metallurgy.