Microstructure And Properties Of Joints Of C/SiC Produced By On-line Liquid Infiltration Joining Process

Carbon fiber reinforced silicon carbide matrix composite (C/SiC) has many excellent mechanical, physical and chemical properties at high temperature, so its among the candidate materials in the fields of spaceflight, aerial, weapon and nuclear energy. But it's difficult to fabricate complex, multicomponent structures for the limitation of woven methods of C/SiC composites. As a result, the joining of the composites in the applications must be solved. It is very important of the research on the joining of C/SiC composites for the design and applications of C/SiC composites.The On-Line Liquid Infiltration Joining of C/SiC composite with different conditions was carried out. A kind of Ni-base alloy was used as the interlinker and the composites were woven by different ways. By using the three-point bending test, combined with SEM, EDS, the microstructure and the properties of joints of the C/SiC composites were studied. The main contents and conclusions are as follows:1. The fiber reinforced ceramic matrix composites are porosity, and the porosity will decrease with the time of vapor deposition increase during the manufacture of the materials. Based on the characteristic, an on-line liquid infiltration joining process fit for the composites were investigated. The porosity of the composites was controlled and compact process was carried out after the joining was finished, which decreased the damnification of joints as much as possible. The joining method improved the wettability between the interlinker and the composites and the interlinker could infiltrated into the composites, which increased the contact area and improved the properties of the joints.2. The On-Line Liquid Infiltration Joining of 2D C/SiC with different holding times at 1300t was carried out. The strength and the microstructure of the joints were studied, the joining mechanism was analyzed and the best holding time was obtained.3. The On-Line Liquid Infiltration Joining of 3D C/SiC at different joining temperatures with the holding time of 45 min was carried out. The strength and the microstructure of the joints were studied, the joining mechanism was analyzed and the best joining temperature was obtained.4. The effects of the vapor deposition for 60 h on the C/SiC composite joints were studied. The results showed the effects of vapor deposition on the joints produced with different conditions were different.5. The oxidations of the joints of C/SiC composites after vapor deposition at elevated temperature in air were studied. Results showed the joints of composites have good oxidation resistance. After the joints were oxidated at 10001, the strength of the joints can maintain the original value prior to the vapor deposition.