Interlayer lack of fusion Characterization of Direct Energy Deposition Additive Manufactured (AM) Components using Nonlinear Ultrasound

Metal-based additive manufacturing (AM) has recently gotten a lot of interest in the automotive, oil and gas, aviation, and aerospace industries for constructing complicated components and parts. One of the most critical types of defect in products manufactured using this method is interlayer lack of fusion of the printed components. The traditional ultrasound techniques are unable to reliably detect and quantify such defects if the impedance mismatch of the defects with the surrounding materials is not significant. The interlayer lack of fusion transmits the majority of the sound energy in traditional ultrasonic testing procedures, reducing detection capabilities in pulse-echo or transmission inspection modes. However, nonlinear ultrasound techniques have shown promise in detecting similar defects like fatigue cracks that have the same limiting detection condition. Usually changes in the frequency domain are considered as damage sensitive feature for defect detection and evaluation. In this study, phase-space domain is used as a complementary domain to frequency domain to investigate the behavior of nonlinear ultrasound waves because of internal lack of fusion in the Direct Energy Deposition (DED) additive manufacturing process. the early experimental results on samples showed that this technique can be utilized to characterize the interlayer lack of fusion in the parts created using the metal-based AM process.