Measurements of fracture toughness of ceramic thin plates through single-edge V-notch plate method

Round-robin tests on the single-edge V-notch plate (SEVNP) method were conducted successfully to evaluate the fracture toughness of Al2O3, AlN and Si3N4 thin plates whose grain sizes were more than 2 μm. A straight-through notch was introduced into a plate with the thickness of 0.32 or 0.64 mm and sharpened by means of razor blade with diamond pasts to prepare a V notch. The V-notched thin specimens were loaded in a special 3pt-fixture with a vertical thin slit to determine the flexural strength. Reasonable consistencies in the resultant fracture toughness were attained between laboratories regardless of the thickness of ceramic plate, indicating the SEVNP method can be an effective test technique for measurements of fracture toughness of the ceramic thin plates.