Microstructural evolution of tungsten carbide-cobalt alloys.

摘要

The microstructural development and grain coarsening behavior of WC-Co alloys, with and without a VC additive, has been investigated. The primary goal of this study was to determine the mechanism through which VC acts as a grain-growth inhibitor.; The study involved long-time sintering experiments (1 to 100 hours) on fully dense material, nascent stage sintering (90 to 1320 seconds) starting with the green compact, and surrogate liquid phase experiments to characterize the WC powder prior to sintering. Quantitative microstructural analysis using intercept length distributions was performed for the long-term sintering. The nascent stage experiments involved the measurement of the specific surface area (S{dollar}sb{lcub}rm v{rcub}){dollar} of each type of interface separately allowing the determination of the contribution of each developing entity to the overall microstructural evolution.; The VC addition has been found to enhance the breakup of multi-grained particles in the earliest stages of sintering, producing a reduced WC grain size. Further coarsening and microstructural development was found to be insensitive to the presence of the VC addition.