A test method to evaluate the fracture toughness, KIC, of thin, small, precracked ceramic specimens is described. The method is applicable for thin plates, wafers, self-supported layers, etc., especially when a large amount of material is not available for testing. The method consists of bonding a small, thin single-edge notched beam on one side of a metallic beam. A stress-free precrack with a square root singularity is achieved when the assembly is deformed in three-point bending. The fracture toughness of a thin, alumina single-edge precracked beam was evaluated experimentally using this method, and compared with that obtained for similar specimens having a 0.3-mm-wide machined notch. Comparison with previously reported fracture toughness values suggests that even a very sharp machined notch overestimates the evaluated fracture toughness.
|Number of pages||3|
|Journal||Journal of the American Ceramic Society|
|State||Published - Jul 1997|