ÖNORM EN ISO 18756

This International Standard describes a test method that covers the determination of fracture toughness of monolithic ceramic materials at room temperature by the surface crack in flexure (SCF) method. This International Standard is intended for use with monolithic ceramics and whisker- or particulate-reinforced ceramics that are regarded as macroscopically homogeneous. It does not include continuous-fibre reinforced ceramic composites. The test method is applicable to materials with either flat or rising crack growth resistance curves. This method is similar to ISO 15732 except that precracks are smaller and are made by a different procedure. The methods should produce similar or identical results for materials with a flat R-curve. NOTE This test method is usually applicable to ceramic materials with a fracture toughness less than 10 MPa m1/2. It may be difficult to form precracks with a Knoop indenter for materials with greater fracture toughness or those materials which are soft (low hardness) such as some zirconias, or for porous ceramics.