Increasing the abrasion resistance without decreasing the toughness of WC-Co of a wide range of compositions and grain sizes

The results presented in this paper show that the abrasion resistance of WC-Co alloys can be increased by increasing the WC grain size while keeping the hardness constant, within a wide range of compositions and grain sizes. The cobalt content must be decreased in order to keep the hardness constant when increasing grain size, but the results show that the mean free path in cobalt (lambda) increases with increasing grain size (d) at constant hardness, although the ratio lambda/d decreases. The increase in mean free path can explain the increase in toughness at constant hardness and larger grain size observed in a wide range of alloys, while the decrease in lambda/d ratio can explain the increase in abrasion resistance. (C) 2006 Elsevier Ltd. All rights reserved.