Spallation of Aluminum Targets Irradiated by Pulsed Laser Beam

The experiments on spallation of aluminum targets irradiated by the Nd: glass laser beam with 4 ns FWHM and flux of (2~5)1011 W/cm2 are reported in this paper. The spall occurred under the supercritical condition, and the spall thicknesses of 0.1 mm and 0.2 mm thick aluminum target are (176) m and (355) m respectively. The threshold spall thickness as a function of target thickness has been estimated for the laser induced shock loading with the strain rate over 107 s-1, and the spall strength of aluminum can reach up to 5~6 GPa at such ultrahigh strain rate.