Spall and Dynamic Yielding of Aluminum and Aluminum Alloys at Strain Rates of 3x10$^{6}$ s$^{-1}$

We have explored the role that grain size, impurity particles and alloying in aluminum play in dynamic yielding and spall fracture at tensile strain rates of $\sim $3x10$^{6}$ s$^{-1}$. We achieved these strain rates shocking the aluminum specimens via laser ablation using the Z-Beamlet Laser at Sandia National Laboratories. The high purity aluminum and Al-1100 produced very different spall strengths and nearly the same yield strengths. Various grain-sized Al + 3 wt. {\%} Mg specimens presented the lowest spall strength, but the greatest dynamic yield strength. Fracture morphology results and particle analysis will be presented along with hydrodynamic simulations to put these results in context with previous publications. Impurity particles appeared to play a vital role in spall fracture at these fast strain rates. With respect to dynamic yielding, alloying elements such as Mg seem to be the dominant factor.