Melting of shock-compressed metals in release

Abstract

Parameters of shock waves that cause melting of aluminum, copper, titanium, and molybdenum in release have been measured. A pulsed proton beam was used to launch 20 to 50 μm thick aluminum flier plates of ∼8 mm diameter up to velocities of 5 to 10 km/s. As a result of the power density profile of the beam, the radial velocity distribution of the flier was bell-shaped and a range of shock pressures was covered by impact of the flier plate in each shot. Acceleration of the flier and the sample free surface velocities were recorded simultaneously using line-imaging version of the ORVIS laser velocimeter. The sharp loss of the sample surface reflectivity was considered indicative of melting.