Slip-line spacing in ZrB2-based ultrahigh-temperature ceramics

Macroscopic manifestation of microscale plasticity at room temperature in the form of slip-lines has been elusive in brittle solids. Recently, such a phenomenon has been reported in ZrB2 ceramics and ZrB2–SiC composites, where slip-lines were detected in room-temperature deformation. Here we show that the slip-line spacing increases with grain size in these ceramics and their composites. Such behavior has been rationalized on the basis of geometrically necessary dislocations and the role of grain boundaries and interfaces.