Micro-scale deformation of gypsum during micro-indentation loading

► Micro-scale deformation and fracture of gypsum under Vickers loading was examined. ► At lower loads: dislocation saturation and localized necking was observed. ► Load increase: increase in subsurface cracking and surface smoothness. ► Smoothness related to plastic flow of water-reduced gypsum (Raman measurement). ► Voids left by evaporated water (118-142 °C) enable gypsum to deform more easily.