Ultrasonic nondestructive characterization and its role in the development and implementation of additive manufacturing processes

Advancements in manufacturing processes, such as metal 3D printing, are deeply reliant on our understanding of the resulting internal features and microstructures that dictate material behavior. Microstructure characterization is often relegated to techniques that require extensive sample sectioning and surface preparation, which are inherently limited to a small portion of the bulk material. In this presentation, I will show how elastic wave propagation methods (namely, ultrasonic testing) can be combined with physics-based models to extract microstructural parameters in fit-for-service parts. Example results are given for binder jet printed metals (namely, stainless steel 316 and SS316 infiltrated with bronze) where microstructure is characterized over large volumes nondestructively. These methods are correlated to both destructive metrics of microscale features and mechanical properties, which are linked to processing conditions and sample geometry. Finally, I will provide a broader outlook for the impact these techniques may have on the development and implementation of quality assurance protocols for additively manufactured parts.