CAREER: Metal Additive Manufacturing of Reused and Recycled Feedstock

This Faculty Early Career Development (CAREER) award supports research investigating the reuse and recycling of feedstock in the laser directed energy deposition metal additive manufacturing process in the context of a circular economy where resources are used as long as possible. This process allows for fabrication or extension of a component’s service life through remanufacturing and repair, specifically for large components for energy applications, like hydropower turbines.

This award aims to support research that attempts to reveal how reused and recycled metals can introduce unique chemistries, structures, and properties for improved large components. The research is expected to provide an understanding of how manufacturing can overcome challenges in the qualification and certification of components, leading to more reliable parts, and fueling the US economy.

Educational activities will contribute to workforce development for graduate research students and for local high school students so they can succeed in a competitive global market. These activities include development of videos on imaging science, international research collaborations, and engagement through a local recycling center in Columbus, Ohio.

The research objective is to reveal how characteristics of reused and recycled feedstock influence melting and solidification in the laser directed energy deposition additive manufacturing process, specifically on how tramp elements and the morphology of feedstock influence melting, oxidation, particle segregation, intermetallic phase formation, and overall microstructure. The research approach includes in situ and operando experimental methods, including synchronized high-speed synchrotron X-ray imaging and diffraction to capture phase transformations during solidification in real-time and at multiple scales.

The scientific objectives address the following: (1) Melt flow changes from reused and recycled material, where increased oxidation and tramp elements from feedstock exhibit lower surface energy in the laser-induced liquid melt pool, reversing Marangoni flow and increasing melt pool flow velocities; (2) Melt flow changes from reused and recycled material physical characteristics, where increased irregularity in shape introduces melt pool flow turbulence during deposition, which breaks up intermetallic phase formation and refines grain growth during solidification; (3) Solidification changes with reused and recycled material resulting from melt flow changes and particle segregation for refined grain growth. Addressing these objectives intends to: create a framework for feedstock reuse and recycling for metal additive manufacturing, extend reuse to material and process systems where material recycling rates low, and elongate the service life of repaired or remanufactured components.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.