Ultrasonic and Acousto-Ultrasonic Inspection and Characterization of Titanium Alloy Structures

Abstract

Research and development in Titanium (Ti) fabrication technology, such as Super Plastic Forming/Diffusion Bonding (SPF/DB), honeycomb (H/C) or composite Titanium-Graphite (TiGr) sandwich panels, requires parallel development of advanced nondestructive evaluation (NDE) techniques to establish high confidence levels in the critical airframe structures being produced. This particular effort is a subset of other NDE work directed towards developing a technique for inspecting and characterizing large area Ti aerospace wing structures. Ultrasonic NDE C-scans using pulse-echo or through-transmission test configurations, in general, are not able to quickly sort large sections of material into acceptable and flawed categories. Conventional ultrasonic configurations using plate-waves are more applicable to large area inspection, while Acousto-Ultrasonics¹ (AU) is a more unconventional NDE technique which has the potential for rapidly correlating extracted waveform attributes to flaw category and mechanical performance, for the area of material being insonified.