Effect of crack growth dynamics on the rate-sensitive behavior of hot-pressed boron carbide

We discuss the dynamic failure of armor-grade hot-pressed boron carbide (B4C) under loading rates similar to 5 x 10(-6) to 200 MPa mu s-1. High-speed photography is used in conjunction with real-time stress measurement during high-rate loading. Compressive strength of this ceramic is found to be relatively rate-in sensitive over this range of loading rates. We use crack growth dynamics to compare the behavior with that of hot-pressed SiC-N and sintered alpha-SiC and find that the defect density has a strong influence on rate dependence. (c) 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.