MSE Colloquium: Sarah Wolff, Capturing laser-matter interactions in directed energy deposition metal additive manufacturing

Dr. Sarah Wolff

Assistant Professor,
Department of Industrial & Systems Engineering
Texas A&M University

Abstract

Laser-based additive manufacturing processes for high-melting point materials are promising for their fabrication of lightweight and high-strength components with complex geometries. These processes, particularly directed energy deposition, provide unique opportunities to design for novel materials with improved mechanical behavior and desirable chemical compositions. However, a key challenge is the control of the final structure, which starts with understanding why porosity or unique microstructures occur in the final part. Experiments at the Advanced Photon Source at Argonne National Laboratory use high-speed X-ray and thermal imaging in real-time to reveal solidification mechanisms with microsecond resolution. Resulting observations include how pores form during the powder-blown process, how melt pool flow changes with powder deposition, how melt pool flow changes with an external magnetic field, and how laser processing can alter the miscibility of dissimilar materials. These fundamental experiments allow for exploration in tuning materials and laser parameters in real-time. With a better understanding of metal additive manufacturing processing, we can improve the fabrication of complex components for rapid qualification and understand how to process new materials.

Bio

Sarah Wolff is an assistant professor in the Department of Industrial and Systems Engineering at Texas A&M University. She completed her PhD in mechanical engineering at Northwestern University in 2018 with her thesis work on the laser-matter interactions in the directed energy deposition additive manufacturing process. Following her PhD, she was an Enrico Fermi fellow at Argonne National Laboratory where she spent half of her time with the Applied Materials Division and the other half with the X-ray Science Division. Her work focuses on using in-situ monitoring, notably X-ray techniques, to reveal the fundamentals of melting and solidification during additive manufacturing processes.

Wolff Research Lab: https://wolff.engr.tamu.edu/