Abstract
In this study, the nondestructive evaluation (NDE) of a compound defect in the weld metal of an aluminum plate has been demonstrated using a photoacoustic microscope (PAM). The compound defect is the blowhole which occurred in the weld metal by welding. The experiments were carried out at different modulation frequencies to obtain the depth profiling by changing the thermal diffusion length. Furthermore, X-ray tomographic imaging and scanning laser microscope (SLM) were also used for comparison with the obtained PAM images. The separation of surface and internal defects were well performed by changing modulation frequency, and PAM measurement agreed well with X-ray micrograph and SLM measurements.
