New results on the relationship between hardness and fracture toughness of WC-Co hardmetal

Two sets of WC-Co grades were produced, with cobalt content ranging from 3 to 50 wt.%. The mean grain size of the two sets was 2.2 and 6 μm respectively. The two sets of grades were used to investigate the relationship between hardness and fracture toughness. It was found that at constant WC grain size the relationship is linear. It was also found that in the low toughness range, grades of equal toughness have higher hardness if their grain size is finer and vice versa for grades of high toughness.