General Electric (GE) has developed silicon carbide fiber reinforced SiC-Si matrix composites by silicon melt infiltration (MI) for use in gas turbine engine applications. This paper focuses on a process based on tow prepreging and lamination of unidirectional tapes. Silicon melt infiltration yields a fully dense, near net shape composite with a relatively high thermal conductivity, actually higher than many superalloys at temperatures up to 800°C, and a high proportional limit, or matrix cracking stress. Room and elevated temperature mechanical properties of the composite are presented. Following exposure to various simulated turbine environments this material shows relatively good retention of strength and toughness. The fabrication of turbine shroud and combustor liner components for high pressure combustion rig testing is also described.

GE has developed SiC fiber reinforced SiC-Si matrix composites produced by silicon melt infiltration (MI) for use in gas turbine engine applications. High temperature, high pressure combustion rig testing and engine testing has been performed on combustor liners and turbine shrouds made from such MI composites. Frame 5 sized combustor liners were rig tested under LHE diffusion flame conditions for 150 hours, including 20 thermal trip cycles, with no observed damage to the ceramic liners. Similarly, 46 cm diameter, single piece turbine shroud rings were fabricated and tested in a PGT-2 gas turbine engine. The fabrication and testing of both components are described.