Estimation of R-curve in WC/Co cermet by CT test

Cemented tungsten carbide is the most popular material for making cutting tools. During machining process the cutting tools are subjected to varying high mechanical and thermal stresses leading to initiation and propagation of the crack in the material. The aim of this paper is to develop a new methodology in order to estimate crack resistance and R-curve behavior of WC/Co composite. The measurement was done by compact tension (CT) specimen test. Obtained results lead to the conclusion that the shielding effect in the cermet is in the region behind crack tip. The increase of the fracture toughness in comparison to pure WC is very high and reaches plateau of 12.6 MPa m1/2 after overall crack extension of 310 μm.