Feasibility of polarized laser scattering in detecting the grinding-induced subsurface damage in SiCf/SiC ceramic matrix composite

Given the urgent demand in the effective method for detecting the machining-induced damage (MID) of ceramic matrix composite (CMC). This study first time proposes the polarized laser scattering (PLS) method to detect the grinding-induced damage of silicon carbide fiber reinforced silicon carbide (SiCf/SiC). The feasibility of the PLS detection is demonstrated. Moreover, the sensitivity of PLS detection is found dependent on the radiation spot size of the laser beam. Decreasing the radiation spot size, the sensitivity to MID increases. However, the sensitivity to the pre-existed defects also increases, which would disturb the detection of MID. While increasing the radiation spot size, the intensity of the PLS detection decreases. In this study, when the radiation spot size is 66, 132, or 264 mu m, the PLS method is suitable for detecting the grinding-induced damage of SiCf/SiC. This study is important for expanding the detection of the MID of CMC.