Sintering of mixtures of powders: Experiments and modelling

Powder metallurgy allows composite materials, notably metal–ceramic composites, to be produced by sintering a mixture of powders. This work analyses the sintering behaviour of metal powder mixed with ceramic inclusions. Experiments have been performed with mixtures of copper and alumina particles of about the same size and volume fractions of alumina between 5 and 30%. The densification kinetics of powder mixtures have been deduced from dilatometry measurement and the microstructure of sintered materials has been observed by scanning electron microscopy. The sintering process has also been modelled by using discrete element method. From both experimental and simulation results the effect of inert inclusions on the densification of metal-ceramic powder mixtures during free sintering is discussed. We found in particular that the densification was significantly delayed even for a volume fraction of inclusions as low as 5% and strongly hindered when this content got to 20%.