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Abstract
The relationship between the mechanical properties and the structure of the sintered carbide WC–TiC–Co has been studied. Specimens containing 7 and 15% cobalt were sintered at temperatures between 1350 and 1550°C (1625 and 1825 K), for times varying from 
to 32 h. The structure was examined by electron. microscopy. Density, coercive force, hardnesss, transverse rupture strength, and energy of crack initiation were determined.
The rate of grain growth is governed by the rate at which the carbide dissolves in the cobalt phase. The activation energy for growth was found to be 120 ± 15 kcal/mol (500 ± 63 kJ/mol).
The coercive force is a linear function of the specific grain surface rather than of the specific cobalt surface. The hardness of alloys with different cobalt contents is a function of a single structure parameter [(1– fβ)/fβ]Sγγ, where fβ is the volume fraction of β phase and Sγγ is the specific grain-boundary surface.
It has been suggested that transverse rupture strength should vary as the square root of the specific grain surface. The present results tend to confirm this suggestion. The energy of crack initiation is highly dependent on the contiguity of the carbide phase.
Notes
* Manuscript received 16 June 1969.