Localized plasticity in silicon carbide ceramics induced by laser shock processing

This paper investigates how laser shock processing (LSP) changes the microstructures and mechanical properties of polycrystalline alpha-SiC ceramics. Three-dimensional (3-D) topography suggests that the grain boundaries experience larger height changes and deformation than the grains after LSP. Transmission electron microscopy characterizations revealed dislocation activities near the surface and grain boundaries in LSP-treated SiC ceramics, suggesting that localized plasticity could be generated during the LSP process at room temperature. X-ray diffraction analysis shows that significant compressive residual stress was introduced in SiC surfaces, which could be extended to a depth of 750 mu m below the surface. The LSP-induced localized plasticity can improve the mechanical properties of ceramics, such as the apparent fracture toughness and bending strength.