Mechanical test discriminability for WC hardmetals

Abstract

How good are the commonly used mechanical property tests for discriminating between materials of different types? In a preliminary exercise to examine this question, two experimental 6 wt % Co/WC hardmetals were prepared with small differences in particle size distribution. Although manufactured from the same WC powders, one specimen contained a distribution of small Co regions, several micrometres in diameter, while the other specimen was structured with the more conventional uniform distribution of Co and WC. These two materials were tested at room temperature using six different methods: hardness, bend strength, notched bend strength, plane strain fracture toughness, indentation fracture toughness and abrasion wear. The results of the tests are described in detail and it is shown that of the six tests only two, notched bend and abrasion wear were able to discriminate between the two experimental materials.