A theory for the shock-wave consolidation of powders

Abstract

A model for the shock consolidation of powders is developed which predicts, for a given powder density, the regimes of shock pressure P and shock duration t d expected to yield fully densified compacts of near optimum strength. Most of the densification work is assumed deposited near particle boundaries, leading to partial melting. The model gives an upper bound to the amount of melt. The condition that the melt between particles must exceed a critical thickness and must solidify within the duration of the shocked state leads to necessary conditions for P and t d .These requirements are presented in “maps of shock consolidation,” using normalized parameters. The model predicts that for a shock energy (normalized to that required to heat iron to the melting point) of 0.7, a minimum shock duration of 2μs is required to consolidate 60μm diameter iron-based powder.