MICROSTRUCTURAL EVOLUTION DURING LIQUID-PHASE SINTERING OF HIGH-SPEEDSTEEL-BASED COMPOSITES CONTAINING TIN-COATED AL2O3, TIC, OR AL2O3 PARTICLES - INFLUENCE ON WEAR PROPERTIES

A high-speed steel containing 1 0 vol % TiN-coated Al2O3, Al2O3, or Ti C particles was liquid-phase sintered with the addition of copper-phos phorus. The mixtures were sintered in a furnace with a controlled axia l temperature gradient, and their microstructural evolution during sin tering was studied using quantitative image analysis. Additional sampl es were fully densified and tested using a pin-on-disc tribometre. Int erfaces were characterized by transmission electron microscopy. The fi nal microstructure depended on the behaviour of the liquid phases surr ounding the ceramic particles during sintering, which was different fo r the three types, of particles used, and influenced the wear resistan ce.