Time-resolved shock compression of porous rutile: Wave dispersion in porous solids

Rutile (TiO2) samples at 60% of solid density have been shock‐loaded from 0.21 to 6.1 GPa with sample thickness of 4 mm and studied with the PVDF piezoelectric polymer stress‐rate gauge. The technique uses a copper capsule to contain the sample which has PVDF gauge packages in direct contact with the front and rear surfaces. A precise measure is made of the compressive stress wave velocity through the sample, as well as the input and propagated shock stress. The initial density is known from the sample preparation process, and the amount of shock‐compression is calculated from the measurement of shock velocity and input stress. Shock states and re‐shock states are measured. The observed data are consistent with previously published high pressure data. It is observed that rutile has a ‘‘crush strength’’ near 6 GPa. Propagated stress‐pulse rise times vary from 234 to 916 nsec. Propagated stress‐pulse rise times of shock‐compressed HMX, 2Al+Fe2O3, 3Ni+Al, and 5Ti+3Si are presented.