ULTRASONIC NDT OF TITANIUM DIFFUSION BONDING WITH GUIDED-WAVES

An ultrasonic guided wave technique is developed for the NDT of diffus ion bonded titanium-to-titanium structures. A three-layer model based on the normal beam experimental results has been proposed. Dispersion curves and wave structure are analyzed to direct the experimental stud y. Two features related to Lamb waves propagating in diffusion bonded titanium plates, the spectral peak to peak ratios and the wave mode fr equency shift, are extracted from the guided wave experimental results for both 2 mm (0.08 in.) and 4 mm (0.16 in.) diffusion bond panels. I t is found for some specific modes and frequencies that these two feat ures are sensitive to the diffusion bonding states and, therefore, cou ld be used to distinguish good bond panels from poor bond ones.