Ultrasonic characterization of components manufactured by direct laser metal deposition

Direct laser metal deposition (DLMD) is an innovative additive technology becoming of key importance in the field of repairing applications for industrial and aeronautical components. The performance of the repaired components is highly related to the intrinsic presence of defects, such as cracks, porosity, excess of dilution or debonding between clad and substrate. Usually, the quality of depositions is evaluated through destructive tests and microstructural analysis. Clearly, such methodologies are inapplicable in-process or on repaired components. The proposed work aims to evaluate the capability of ultrasonic techniques to perform the mechanical characterization of additive manufactured (AM) components. The tested specimens were manufactured by DLMD using a nickel-based superalloy deposited on an AISI 304 substrate. Ultrasonic goniometric immersion tests were performed in order to mechanical characterize the substrate and the new material obtained by AM process, consisting of the substrate and the deposition. Furthermore, the relationship was evaluated between the acoustic and the mechanical properties of the AM components and the deposition process parameters and the geometrical characteristics of multiclad depositions, respectively. Finally, the effectiveness of the proposed non-destructive experimental approach for the characterization of the created deposition anomalies has been investigated.