Abstract
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.
Highlights
As defined by the American Society for Testing and Materials International (ASTM), additive manufacturing (AM) is a manufacturing process in which the components are produced by addition and not subtraction of material [1]
In [18] the ultrasonic backscattering data generated by the microstructure of the additive manufactured (AM) material produced by selective laser melting (SLM) process were evaluated using the ultrasonic immersion C-scan system
Another non-contact ultrasonic method was proposed in Cerniglia et al [19], consisting of the innovative laser ultrasonic technique that was employed for the inspection of laser powder deposition (LPD) components in order to detect near-surface and surface defects
Summary
As defined by the American Society for Testing and Materials International (ASTM), additive manufacturing (AM) is a manufacturing process in which the components are produced by addition and not subtraction of material [1]. In [18] the ultrasonic backscattering data generated by the microstructure of the AM material produced by selective laser melting (SLM) process were evaluated using the ultrasonic immersion C-scan system Another non-contact ultrasonic method was proposed in Cerniglia et al [19], consisting of the innovative laser ultrasonic technique that was employed for the inspection of laser powder deposition (LPD) components in order to detect near-surface and surface defects. By means of the proposed experimental approach, the variation of the acoustic response (in terms of TOF and of the velocity of the ultrasonic waves) and of the mechanical response (in terms of the elastic moduli) of the AM components was evaluated as a function of the deposition process parameters and of the geometrical characteristics of multiclad depositions ( the average clad height). Further experimental campaigns are ongoing in order to mechanical characterize the AM components that exhibit anisotropic mechanical behavior
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