Effect of boron on the WC morphology in sub micron tungsten carbide-aluminide composites
The effect of boron on the WC morphology and on the grain size of binders in sub micron WC composites containing Fe60Al40 and Ni3Al binders was investigated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The composites were prepared under uniaxial hot pressing of milled powder samples at 1500 ºC in inert argon atmosphere. Doped aluminides with boron levels ranging from 0 to 0.1 wt% were used as the binders. It was found that the microstructural characteristics of boron doped aluminide WC composites were similar to those of hot pressed WC-Co and commercial grade WC-10wt%Co (H10F) hardmetals. The contiguity of WC particles (WC/WC contact) and the grain sizes of aluminides decreased and the extent of faceting of tungsten carbide increased in the aluminide tungsten carbide composites in presence of boron.