Materials science of cemented carbides — an overview

Abrasive wear of tungsten carbide—cobalt composites. I. Rotary drilling tests

Phase size distribution in WC/Co hardmetal

SUMMARY

This article gives a survey of the actual experience with the relatively new technique of photo-emission electron microscopy. After describing the principal technique and the features of a modern high resolution instrument, the questions of image generation, contrast formation and resolution are considered. In particular the influence of the depth of information on resolution for flat polished sections is studied and some comparisons with the scanning electron microscope (SEM) are made.* The different fields of application of the photo-EEM are shown by examples.

The photo‐emission electron microscope: Its technique and applications

Crack initiation, crack propagation, fracture modes, fracture toughness, strength, and critical defects of hardmetals at room temperature are reviewed. The state of the art for the structure-property relations that are based on a variety of chemistry, geometry, residual stresses and defects of the microstructure is discussed with major emphasis on the modern models and understanding of the processes and mechanisms behind the mechanical properties of hardmetals. Future research directions that seem appropriate at the moment are outlined.

Fracture and Strength of Hardmetals at Room Temperature

The paper reviews work demonstrating the importance of carbide particle and grain size as regards the preparation and the properties of cemented carbides, and considers the techniques of particle- and grain-size measurement. It is shown that the initial size of the carbide powder influences the grain size in the sintered structure. Means of size-distribution analysis are evaluated. Some problems of accurate quantitative structure analysis and its automation are discussed. The best methods at present available for routine and basic work are outlined and modern devices are described.

H. E. Exner

Papers

Methods and significance of particle and grain-size control in cemented carbide technology*