Chapter 2 - Strength and toughness of ceramic composites at elevated temperatures

Abstract

This chapter provides a brief review of the strength and toughness of both the whisker-reinforced ceramic matrix composites and fiber-reinforced ceramic matrix composites at elevated temperatures. Whisker-reinforced ceramic composites have come into prominence for structural applications because of their potential for high strength and fracture toughness, which can be retained at elevated temperatures. This chapter gives an understanding of the characteristics and toughening behavior of whisker-reinforced ceramic composites. Research into the toughening behavior responsible in the composite materials shows that crack-whisker interaction resulting in crack bridging, whisker pullout and crack deflection are the major toughening mechanisms. Whisker-reinforced composites' toughening behavior and increases in toughness are dependent on the parameters such as whisker strength, volume fraction of whiskers, elastic modulus of the composite and whisker, whisker diameter, and interfacial fracture energies. The chapter also enables readers to have an understanding of the characteristics of fiber-reinforced ceramic matrix composite and its strength degradation mechanisms at elevated temperatures. Fiber-reinforced ceramic composites with satisfactory strength and toughness at elevated temperatures have not been achieved so far. The chapter also addresses the critical issues and limitations of Fiber-reinforced ceramic composites.