Measurements of Scattering from Bulk Defects

This report presents results of measurements of longitudinal wave ultrasonic scattering from complex defects embedded in Ti-alloy by the diffusion bonding process. The defects examined are: circular and elliptical cracks, two overlapping voids consisting of a sphere and a prolate spheroid, two adjacent spherical voids, and a spherical void with an encircling crack. Representative plots are given for the raw waveforms, magnitude (and sometimes the phase) of the deconvolved Fourier transform, and in some cases the time impulse response function. The data are compared to or analyzed in terms of several current theories. While good quantitative agreement was observed over certain ranges, the comparisons point to definite (in some cases not unexpected) limitations in either the pertaining theory or experiment or both. Finally, the results are discussed with an eye toward applications