Optimization of the delta technique and application to the evaluation of electron-beam welded titanium aircraft parts

Abstract This paper deals with the development of a non-destructive method for detecting a tight lack-of-fusion defect in electron-beam-welded titanium aircraft parts. The method is based on the ultrasonic delta technique. A combined experimental and theoretical approach is used in this study. The objective of this work is to provide potential users of the technique with guidance for choosing operating frequencies, incidence angles, ultrasonic beam sizes and other experimental parameters so as to maximize the signal-to-noise ratio during use of the delta technique. To achieve its objectives, the paper studies the influence of the material microstructure on the ultrasonic response. Keywords: Titanium AlloysUltrasonic Delta TechniqueNon-destructive EvaluationUltrasonic AttenuationElectron-beam Welds