Toughening strategies for MoSi2-based high temperature structural silicides

The key materials issue associated with the future of high temperature structural silicides is the improvement in the low temperature fracture toughness of these materials. Many industrial applications require materials with fracture toughness levels in the vicinity of 10 MPa m1/2, while turbine applications require toughness levels of 15 MPa m1/2 or higher. Two important routes currently being pursued to increase silicide fracture toughness are the composite approach and the alloying approach. Composites based on the reinforcement of MoSi2 with ceramics are discussed. Alloying approaches for MoSi2 based on limited theoretical guidance are outlined.