Creep Deformation of 0° Sapphire

Abstract

Creep deformation of 0° sapphire was studied between 1600°and 1800°C at stresses up to 114 MN/m². Microscopical evidence (dislocation structures observed by transmission electron microscopy (TEM) and by etch pits) suggested that Nabarro climb was the predominant deformation mechanism. Both the experimental creep rates and stress exponents were in good agreement with those predicted by this model. Although non‐basal dislocations with a ½〈101〉 Burgers vector were present, the good creep resistance of 0° sapphire was attributed to the difficulty of activating pyramidal slip.