Influence of bulk and interfacial properties on shock compression of metal powders. II. Compaction of clusters of particles

Abstract

During compaction of large ensembles of metallic particles, the deformation and redistribution of the particles are strongly influenced by the bulk and interfacial properties of the interacting materials. Using a sharp-interface Eulerian approach, this paper studies the physics of shock compaction of clusters of particles by accurately capturing the interfacial dynamics of particle-particle interactions. The effect of disparity in bulk material properties such as impedance and yield strength and interfacial phenomena such as friction are quantified using interfacial area evolution as a measure of mixing of the materials. The results show that friction between the particles increases the mixing of the materials only for lower initial theoretical mean densities but does not significantly affect the overall dynamics of the compaction. The deformation and contact between the particles are most strongly influenced by the impedance mismatch of the materials. The difference in yield stress plays a minor role due to the predominance of pressure over deviatoric stresses. The results provide insights into the individual effects of impedance and yield stress mismatch between material pairs and also into the combined influence of mismatches in both properties. It is shown that apart from property mismatch, the average impedance of the mixture also plays a key role in mixing of the materials.