Field Joining of Ceramic Matrix Composites

Silicon carbide fiber and carbon fiber reinforced silicon carbide composites are being considered for reusable launch vehicle airframe components. Because the furnaces needed to make components are expensive, and furnaces of the size needed to make airframe components simply do not exist, we need a way to join these composites together to make complex and large shapes. TDA proposes to address this problem by using welding equipment to join C/SiC and SiC/SiC composites. In Phase I, we demonstrated the ability to join these composites by producing a reaction-bonded silicon carbide in joints with commercial Gas Transferred Arc Welders at rates of 5 seconds/inch with strengths greater than the parts to be joined. In Phase II, we will optimize this welding/brazing process to produce prototypes including a 10 inch x 10 inch C/SiC joined composite. We will also produce a 1 inch x 6 inch C/SiC composite joined with a silicon alloy to produce a higher temperature capability joint. In addition to aerospace structures these technology will be commercialized in current markets for monolithic silicon carbide.