Construction of SiCnw/MAS nanocomposites to strengthen and toughen C/C-LAS joints

SiC nanowires were in-situ synthesised onto SiC coated carbon/carbon (C/C) composites to construct SiC nanowire reinforced magnesium aluminosilicate (SiCnw/MAS) nanocomposites for strengthening and toughening carbon/carbon-lithium aluminosilicate (C/C-LAS) joints. Polymer impregnation pyrolysis (PIP) technique was applied to prepare high purity SiC nanowires. A layer of SiCnw/MAS nanocomposites with ~ 30 µm was achieved between SiC ceramic coating and MAS interlayer via hot-pressing sintering. As a result of debonding, pulling out and deflecting crack mechanisms of the nanowires, fracture pattern was changed from brittle fracture to pseudo-plastic fracture, accompanied by significantly increased shear strength and enhanced work of fracture. The introduced SiC nanowires could dissipate the energy enquired for crack propagation by arresting and deflecting cracks and contribute to the improved mechanical performance. Shear strength and work of fracture of the PIP SiC nanowires reinforced C/C-LAS joints were improved respectively by 94% and 61%, ascribed to the formation of SiCnw/MAS nanocomposites.