Tungsten heavy alloys are particle composites; they occupy a unique position in materials because of their combination of high density, strength and ductility. The main focus of this study was to examine the effect of sintering conditions (temperature and time) on the microstructural parameters of tungsten heavy alloys. Alloys composed of 88%, 93% and 95% wt. of tungsten and either Ni: Fe (in the ratio of 7:3) or Ni: Co (in the ratio of 7:3) were consolidated into green compacts. Samples of each of the six resulting alloys were sintered in hydrogen atmosphere at different temperatures for different sintering holding times. The microstructural parameters of both types were found to be roughly similar at each temperature and holding time. At higher sintering temperature and longer sintering holding times there was a matrix gradient and the formation of FeNi intermetallic phases at tungsten matrix interfaces. The microstructural parameters showed that the W-Ni-Co alloys may have some advantage as a result of their small tungsten grains and the lower contiguity.