High strain rate response of aluminum 6092/B4C composites

Aluminum 6092/B4Cp (boron carbide) metal-matrix composites (MMC) fabricated by two different powder consolidation routes, extrusion and sintering/hot isostatic-pressing (HIPing), were made and tested over a wide range of strain rates (10(-4) to 10(4) s(-1)). The strength of these MMCs increases with increasing volume fraction of particulate reinforcement. Strain hardening is observed to increase with increasing volume fraction of reinforcement at lower strains (<5%), but tends to be insensitive to volume fraction at higher strains. The composites show significant strain rate dependence. The fabrication route affects the strength of the matrix material, as reflected in the microstructure, and this effect carries on into the corresponding composites. The composites made by the extrusion route show similar strain rate hardening for all volume fractions studied, while the composites produced via sintering/HIPing demonstrate increased strain rate hardening at the higher reinforcement volume fractions. Particle size effect is not significant for the particle size range (>5 mum) considered. Finally, the Li-Ramesh model captures the observed high-rate behavior exhibited by these powder-consolidated composites. (C) 2004 Elsevier B.V. All rights reserved.