Indentation‐induced ductile behavior of glass–ceramics involving layered aluminosilicates

Contact damage in materials is critical in engineering applications because it influences mechanical resistance, such as wear, erosion, and impact failure. Indentation tests were performed using a tungsten carbide ball indenter (Hertzian contact) on the surfaces of glass–ceramics containing hexagonal CaAl 2 Si 2 O 8 or mica crystals (fluorophlogopite), both of which have a layered structure. The stress–strain relation and the permanent deformation on the surface, as well as the observation of the microcrack zone by X‐ray computed tomography using synchrotron radiation, revealed that the glass–ceramic with hexagonal CaAl 2 Si 2 O 8 showed ductility similar to the quasi‐plastic behavior previously observed in the mica glass–ceramic. The yield stresses of the glass–ceramics were estimated from the stress deviating from the stress–strain relation assuming complete elastic response between the ball and the sample. The ratio of the yield stress to Young modulus ( Y / E ) of the glass–ceramic with hexagonal CaAl 2 Si 2 O 8 was determined to be higher than that of the mica glass–ceramic.