Micro-spall investigation in Sn targets using velocity and multi-time X-ray diagnostics in plate impact experiments

When a material is subjected to a Taylor (triangular) shock wave of sufficently high-level to induce its melting under shock or release, the spall strength reduces to a very small value and a volumic damage occurs called micro-spall. An expanding cloud of high-density particles is generated in the bulk. Experimental quantitative observations of this physical phenomenon are complex. In this work, a recent experimental set up is presented. It is dedicated to the investigation of an expanding microspall in Sn targets.

Five plate impact experiments have been performed on a powder gun. Classical diagnostics dedicated to the velocity measurements have been coupled to an original set up allowing a multi-time X-ray observation of the cloud. This experimental results give us quantitative information to evaluate the relevance of microspall modeling.

Velocity measurements and muti-time density distribution are in good agreement with simulations performed with an hydrodynamic code. Different modelling for microspall have been investigated. These informative observations allow us to significantly improve our understanding of the physics of microspall.