Consolidation and high strain rate mechanical behavior of nanocrystalline tantalum powder

High ductility and strength exhibited in nanograined materials can potentially be exploited in explosively formed penetrator liner applications. Both coarse and nanocrystalline tantalum powder were consolidated by Plasma Pressure Compaction ((PC)-C-2) to study the effect of grain size on dynamic compression properties. The powders were consolidated rapidly with I minute of isothermal holding time to retain initial microstructure. The (PC)-C-2 consolidated specimens were cut by electric discharge machining (EDM), polished for SEM characterization and rested in dynamic compression using a Kolsky apparatus. The effect of grain size on yield stress and strain was investigated at various strain rates for a coarse grained and a nanograined specimen. Especially, the high strain rate response of nanocrystalline tantalum is discussed in this paper. (C) 1999 Acta Metallurgica Inc.