A novel technique was developed for toughening brittle materials. The surfaces of a brittle material were damaged at room temperature, followed by annealing at high temperatures. During annealing, cracks (which were introduced during surface damage), disappeared and dislocation sub-boundaries formed. This treatment improved the fracture toughness by a factor of 2.

Toughening of a Brittle Material by Means of Dislocation Sub-Boundaries. W.J.Moon, H.Saka: Philosophical Magazine Letters, 2000, 80[7], 461-6