A STUDY OF FRACTURE TOUGHNESS OF HARDMETALS BY CHEVRON-NOTCHING METHOD

Three-point bending specimen with V shape notch is mainly used for tasting the plane-strain fracture toughness (K_IC) of very brittle materials such as hardmetal, ceramic, etc. This specimen has following obvious advantages over conventional toughness specimen. (1)Simple geometry can easily be machined. (2)No fatigue precracking is required. (3)No crack length measurements are required (K_IC can be directly calculated from knowledge of peak load). (4)Its K_IC was found to be of low dispersity, superior reproducibility and distinctive comparison.Besides, the relation between the K_IC and the main structural parameters λ/D_WC1/2 of hardmetal is also discussed. The result shows that fhere is an excellent linear relation between them.