Multi-staged brazing using the BraSiC process for the fabrication of very large and/or complexe SiC-based components

摘要

The BraSiC process has been developed for brazing SiC based materials for the fabrication of large and/or complex industrial components. It has already been used for the realisation of the largest reflector ever flown in space (diameter 3.5 m) for the telescope HERSCHEL. In order to manufacture complex or larger components (up to 8 m in diameter) for space applications, this process has recently been optimised to perform multi-staged brazing. The principle of this multi-staged brazing consists in brazing SiC elements in several stages, each stage being associated with a filler alloy and a brazing temperature that allow the joining of some parts of the components without melting of the brazed joints already formed in the previous stages. To qualify the multi-stage brazing, a mock-up was designed and brazed with success in two stages thanks to two filler alloys. Mechanical tests have been performed on tests specimens and it has been demonstrated that the properties of the joints formed in the first stage are not decreased after the second brazing. Finally, the mock up was mechanically tested until failure. The failure did not occur in the joints that means the filler alloys are not the weak point of the structure.