Nondestructive Detection of Tilted Surface Defect with Wedge Shape by Photoacoustic Microscopy

In this study, the nondestructive evaluation (NDE) of the tilt angle of a wedge-shaped surface defect has been demonstrated by a photoacoustic microscopy (PAM). The tilted surface defects, the wedge-shaped defect walls of which were tilted against the surface normal direction, were fabricated on a metal plate specimen by mechanical processing. The obtained signal distribution depends strongly upon the tilt angle and wedge shape of the defects. Furthermore, it was shown that the estimation of the complicated surface defect shape was plausible using this method.