TIC-STRENGTHENED AL2O3 BY POWDER TAILORING AND DOPING PROCEDURES

High-carbide Al2O3/TiC composites have been fabricated without hot-pressing by different processing techniques. Transient liquid phase sintering with additions of TiH2 turned out to be the most promising of the doping procedures. The highest strength, (> 800 MPa), however, was measured when omitting all additives and using a tailored alumina raw material with narrow grain size distribution. The influence of the alumina grain size distribution on sintering and strength is discussed as being associated with the amount of grains and aggregates larger than 1 mum and with the mutual homogenization of oxide and carbide components. In contrast, the reduction of the median powder grain size plays a minor role only.