COMPACTION AND SINTERING CHARACTERISTICS OF COMPOSITE METAL POWDERS

The compaction and sintering characteristics of composite metal powder s are examined using aluminium-copper, aluminium-iron and copper-iron powders. The density of a composite green compact is predicted based o n the compacting pressure-density curve of each powder. The effects of the volume fraction of the mixed powders and the sintering temperatur e on the density and hardness of a sintered part are also examined Exp erimental results show that the density of the composite green compact can be predicted by the law of mixtures. The density change in the si ntering of the composite green compact depends on the combination and the volume fraction of the composite powders as well as on the sinteri ng temperature. For copper-iron mixed composite powders, the density o f the sintered part increases with increasing sintering temperature an d volume fraction of copper powders, whilst, for the combination of al uminium-copper powders, anomalous behaviour is found; when the green c ompact (50 vol.% aluminium-50 vol.% copper) is sintered at a temperatu re of about 800 K; the density of the sintered part becomes smaller th an that of the green compact. However, the hardness of the sintered pa rt increases remarkably; the micro-Vickers hardness of the sintered pa rt is about 600, which is approximately 15 to 20 times that of the sin tered pure copper and aluminium, respectively. This should be emphasiz ed as one of the important characteristics of sintered aluminium-coppe r composite material.