ISO 21618:2025

This document specifies a test method for determination of the fracture resistance of monolithic ceramics at room temperature using the indentation fracture (IF) method. This document is applicable to dense monolithic ceramics and whisker- or particulate-reinforced ceramics which are regarded as macroscopically homogeneous. This document is not applicable to monolithic silicon nitride ceramics for bearing balls and continuous-fibre-reinforced ceramics composites. This document is applicable for material development, material comparison, quality assurance, characterization and reliability data generation. Indentation fracture resistance, KI,IFR, as defined in this document is not to be equated with fracture toughness determined using other test methods such as KIsc and KIpb. NOTE KI,IFR is an estimate of a material’s resistance to cracking as introduced by an indenter and has correlations with wear resistance and rolling contact fatigue performance as well as machining processes, since these properties are governed by the resistance to crack extension in localized damage areas.[1]-[3] By contrast, fracture toughness properties KIsc and KIpb are intrinsic properties of a material and are relevant to macroscopic and catastrophic fracture events with long cracks rather than those phenomena caused by microscopic and successive damage accumulation associated with short cracks.