Analysis of die compaction of tungsten carbide and cobalt powder mixtures

This paper investigates die compression of tungsten carbide-cobalt powder m ixtures, which is an important step in the processing route of cemented car bides. Simple action compression of miscellaneous mixtures has been investi gated with an industrial type press allowing measurement of the force appli ed on both upper and lower punches. In addition, an original apparatus was used to measure the average radial stress applied upon the die, and the fri ctional shearing force at the powder/die interface was determined through a powder/wall friction apparatus. A mechanical analysis of the data obtained for various tungsten carbide-cobalt powder mixtures provided the intrinsic stress nu. density compressibility relation as well as the radial stress t ransmission coefficient and the powder/die friction coefficient. In this fr amework, the effect of several material and process parameters on the densi fication is discussed.