The disclosed embodiments generally relate to non-destructive evaluation methods. More particularly, the disclosed embodiments relate to ultrasonic non-destructive evaluation methods for the evaluation of friction welded bladed discs (“blisks”). In an embodiment, a method for non-destructive evaluation of a bladed disc structure includes identifying a region of interest on the bladed disc structure; positioning an ultrasonic transducer and receiver in the region of interest; scanning the region of interest using the ultrasonic transducer and receiver to produce a scan image; and comparing the scan image against a reference image to determine the presence of an anomaly in the region of interest.