Experimental Investigation of the Release Isentropes for OFHC Copper

The release isetropes of oxygen-free copper have been measured by explosive loading technique, in which brass is used as the flyer material, copper as the material both for baseplate and sample, and HR2-steel, SiO2-heavyglass, LY12/LF6 Al, MB2 alloy, PMMA and air as the anvil materials. The results showed the measured release isentropes can be described through Grneisen equation of state with constant approximation in the initial releasing pressure range up to 219 GPa, and the relative deviation, (US-2u)/(2u), of the measured end particle velocity, US, with the value of the mirror-line approximation, 2u, increases with increasing initial releasing pressure.