Low-Temperature Joining of SiC-Matrix Composites

The outstanding properties of silicon carbide (SiC) include excellent specific strength, extreme chemical resistance, tremendous hardness, and retention of its high strength at very high temperatures. The brittleness typically associated with a ceramic can be mitigated by forming composites with either carbon or SiC fibers. However, the processes for forming SiC matrix composites limit the size and complexity of the resulting shapes. It is therefore necessary to develop techniques for efficiently joining SiC matrix composite parts. Many such methods have been proposed over the past 25 years, but none is satisfactory, and it remains an active area of research. The joints formed so far either require extremely high temperatures to manufacture or result in unsatisfactory mechanical properties. TDA is herein proposing a route that will result in a pure SiC bond, and will achieve it without requiring any external heat source. As such the joint will be robust, and have the same temperature capabilities and mechanical properties as the matrix. The technology will have met the criteria for exiting technical readiness level (TRL) 3, and some of the criteria for TRL 4, by the end of the Phase I period.