Proposed selection rules for suitable binders in cemented hard metals with possible applications for improving ductility in intermetallics

The results of a selective study of the literature on transition metal binder-hard metals and the parameters that determine the choice of suitable binders are reported. Thermodynamic and kinetic considerations have played a major role in the selection of suitable binders, with the electron theory of metals playing a minor role. It was deduced from the study that the electronic configuration of metals could be a major controlling factor in the thermo-kinetic reactions that take place during sintering in hard metal systems. A set of rules for binder metal selection is proposed based on this study. A modification of these rules would seem partly to explain ductilities currently obtained in certain intermetallics. The application of these rules would point to suitable binder metal(s) selection possibilities that are currently unexplored and predict alloy selection that could improve the ductility of brittle intermetallics.