Very high-temperature Nb-silicide-based composites

This paper describes recent progress in the development of Nb-silicide-based in-situ composites. These composites are being developed for structural applications with service temperatures of up to 1350DGC. From a commercial perspective, investment casting of near netshape components of Nb-silicide composites offers substantial potential because of its proximity to existing airfoil manufacturing practices. However, investment casting techniques are not yet well developed for Nb-silicide composite airfoils. Furthermore, there is only a limited understanding of the relationship between composition, processing techniques and the properties of Nb-silicide composites. Alloying schemes have been developed to achieve an excellent balance of room temperature toughness, fatigue crack growth behavior, high temperature creep performance, and oxidation resistance over a broad range of temperatures. (AU) © TMS (The Minerals, Metals & Materials Society), 2004