STUDY OF THE DYNAMIC COMPRESSION BEHAVIOR OF AN SHS-BASED TiB_2-Al_2O_3 CERAMIC COMPOSITE

摘要

A TiB_2-Al_2O_3 ceramic composite material produced by powder metallurgy from SHS (Self propagating High temperature Synthesis) powders is examined and the characteristics of its dynamic behavior are studied along with a microstructural approach. The ceramic composite material is loaded under high strain rate conditions using Hopkinson bar devices (SPHB) in compression and displays a maximum compression strength of 4.5 GPa. Prior determination of the material mechanical characteristics in quasi-static reveals the influence of strain rate. Analysis of the role played by residual porosities on the development of microcracks leading to the ruin of the samples contributes to a better understanding of the failure mechanisms. On an other hand, the role played by the TiB_2 grains as to reinforce the alumina matrix via a crack deflexion mechanism has been characterized.