Abstract:Considering the classic GriffithOrowan equation of energy balance during fracture and the contribution of the tungsten carbide and the effective cobalt phase volume fraction to the fracture strength, a new theory, which concerns the variations of the fracture strength of WCCo alloys with their microstructural parameters such as the cobalt phase volume fraction and tungsten carbide grain size, was proposed. The predications provided by this theory tally qualitatively well with the experimental results observed by the previous researchers.

Key words: fracture strength cobalt phase volume fraction WC grain size