Prager, Jens; BAM Bundesanstalt fur Materialforschung und -prufung; Germany
Köppen, E.; Federal Institute for Materials Research and Testing (BAM); Germany
Prager, J.; Federal Institute for Materials Research and Testing (BAM); Germany
Ultrasonic inspection of additively manufactured components requires exact knowledge about the acoustic properties of the specific material. Particularly for image reconstruction methods like the Synthetic Aperture Focusing Technique or the echo tomography, the acoustic anisotropy must be considered to achieve an appropriate accuracy of the flaw representation. The layer-by-layer manufacturing process of selective laser melting, as one of the most common manufacturing techniques, results in a specific grain orientation and influences the acoustical and mechanical properties of the material. Additionally, the manufacturing process can result in a porous material also influencing the mechanical strength of the material.
The presented results reveal the relation between the manufacturing process and the acoustic properties of the material. A strong acoustic anisotropy is found. Based on these findings an image reconstruction technique is developed using data from an ultrasonic immersion testing and considering the special geometry and the acoustic properties of the material. The image reconstruction results are compared to results from computer tomography and applied for assessing the porosity of the material. Different aluminum, ferritic, and austenitic materials are investigated.