Loading mode effects on the fracture toughness and fatigue crack growth resistance of WC-Co cemented carbides

The fracture toughness and fatigue crack growth resistance (FCG) of WC-Co cemented carbides under tensile (I), shear (II) and mixed (I + II) loading modes were investigated. It is found that (1) fracture toughness values evaluated under pure loading modes are comparable to one other; (2) FCG rates are enhanced as loading mode varies from pure shear to pure tensile; and (3) FCG threshold in mode I represents the critical condition for FCG initiation in these materials.