Shock Compression of Powders by Two-Stage Gasdynamic Gun

Abstract

Powder consolidation using a shock compression apparatus is a potential method for the processing of bulk materials. Two-stage gasdynamic guns take advantage of light gases properties to accelerate projectiles to hypervelocity. The prototype developed at the CNR-IENI labs was modified in order to densify powders in very short times (1-100 μs). Powder compaction can be achieved either by the generation of a pressure pulse (10-30 104 bar) or by direct impact on the powder sample of a high speed projectile (0.5 - 2 Km/s). A numerical code, to simulate the gasdynamic gun behavior, has been written and, depending on the densification method (pressure pulse or impact) can be used to calculate the pressure and temperature histories in the densification stage or the pellet velocity, momentum and kinetic energy just before the impact. Preliminary experimental tests indicate the capability of this apparatus to densify different kind of precompacted powders.