Ceramics are used in applications requiring strength, hardness, light weight, and resistance to abrasion, erosion, and corrosion, at both ambient and elevated temperatures. However, traditional ceramic materials are characteristically brittle, and this brittleness limits their use. While reduction of brittleness has been obtained with fiber-reinforced ceramic matrix composites, there continues to be a need for materials that combine the desirable properties of ceramics with improved fracture toughness.