Laser-supported joining of SiC-fiber/SiCN ceramic matrix composites fabricated by precursor infiltration

摘要

SiC-fiber/SiCN ceramic matrix composites were manufactured by means of polymer infiltration and pyrolysis. The fiber preform was made by slurry infiltration and winding using a computer-controlled winding module. Multiple infiltration steps using a Si-C-N precursor were included to increase the density. The influence of the sintering conditions on the microstructure of the CMC was demonstrated. Pipe sections made of the CMC materials were joined using a laser-supported heating technology with an Y-Al-Si-O glass-ceramic filler. The thermal response of the CMC components was controlled by the anisotropic thermal conductivity. Fast heating by laser beam was achieved for elements rotating in the direction of the fiber winding. SEM micrographs of the joints showed the good wettability of the CMC by the glass-ceramic filler. Nearly defect-free joints were obtained using a nitrogen process atmosphere. The laser-supported technology was shown to be promising for the joining of CMC components.