The brittle-ductile transition in polycrystalline aluminium oxide

Abstract
A transition from brittleness to ductility in bending was shown to occur in dense, fine-grained aluminium oxide at temperatures from 1300° to 1400°c. The associated increase in transverse rupture modulus was attributed by means of independent pre-strain experiments to the strengthening effect of plastic deformation. Plastic strains of 0.0017 introduced by bending at 1425°c resulted in an increase of 19% in the rupture modulus in subsequent fracture at 1300°c.