Examination of peak stress dependence for tantalum spall when shocked near the spall strength

The spall strength of tantalum has been extensively studied under dynamic loading across a wide range of grain sizes, strain rates, and compression techniques. While these experiments have identified a strong strain-rate dependence on the spall strength, the peak stress imparted to the material during an experiment was typically at least 2x greater than the spall strength. Here we present impact experiments on a single stage light gas gun to examine whether the spall strength in wrought tantalum can be reduced when shocking the material to peak stresses from 4.2-5.4 GPa. A positive correlation was identified between peak stress and spall strength for both as-received sheet and annealed Ta.