Study of Lead Ejection and Dispersion under Shock-Wave Loading and Isoentropic Unloading

This paper presents the results of an experimental study of ejection and dispersion of a lead sample in vacuum after shock-wave loading and isentropic unloading using optoelectronic microscopy and photonic Doppler velocimetry. The dynamics and spectrum of predominantly dispersed particles are studied. Optical visualization is ensured by cutting out an 0.5-mm wide stream from the dispersed cloud using a diaphragm with a slit. The experiments are carried out in a sealed armored chamber. A 1- or 2.5-mm thick sample is loaded with a solid explosive through a metal substrate 1 and 2 mm in thickness. The shock wave intensity varies from about 23 to 38 GPa, and the pressure gradient behind the wave front ranges from 80 to 157 GPa/cm. After the loading, the lead is either in a liquid phase, in a solid phase, or in a mixture of both. It is shown that the particle size distributions of dispersed lead are different at different phase states.