Mechanical Properties of Beta-Silicon Nitride Whisker/Silicon Nitride Matrix Composites.

摘要

Whisker-reinforced ceramic matrix composites have received a great deal of attention for applications as high temperature structural materials in, for example, advanced heat engines and high temperature energy conversion systems. For these applications, where mechanical reliability is critical, the improvements that can be realized in fracture stress and fracture toughness by the addition of whiskers to polycrystalline ceramics are of great interest. The primary role of the whisker reinforcement is to prevent catastrophic brittle failure by activating mechanisms that dissipate energy during crack propagation. Relevant toughening mechanisms include whisker bridging, whisker pullout, crack deflection, and microcrack formation. Of particular importance for optimizing the mechanical reliability of these composites is the effect of the whisker/matrix interfacial characteristics on these toughening mechanisms. (jes)