Fabrication and properties of SiC/Si3N4 multilayer composites with different layer thickness ratios by aqueous tape casting

The influence of residual stresses on the mechanical properties of SiC/Si3N4 multilayer composites with different layer thickness ratios has been discussed. SiC/Si3N4 multilayer composites were prepared via aqueous tape casting, laminating and pressureless sintering. Residual stresses distribution of the composites was obtained by using ANSYS software. Effect of the layer thickness ratios on the properties of composites was investigated. Step-like fracture was found from the load–displacement curves. Obvious extended interfacial delamination, caused by weak interface, was found in the composites which increased the length of cracks and then improved the fracture toughness. High residual stresses is the main reason to the weak interface, thus it is proposed that high residual stresses at the interface may be the main reason to the improvement in fracture toughness and work of fracture.