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ISE Welcomes Sarah Wolff

Synchrotron techniques to monitor and characterize additive manufactured materials


Seminar by Sarah Wolff

Ph.D. Candidate

Mechanical Engineering

Northwestern University


Wednesday, February 7th, 2018


144 Baker Systems

1971 Neil Avenue


Powder-blown and laser-based additive manufacturing processes provide unique opportunities for novel materials design of functional materials with complex component geometries and improved mechanical behavior due to its unprecedented rapid solidification. The nature of the process opens doors to multi-material capability at many length scales. However, the complex physical phenomena that occur during the process lead to uncertainties in structure and mechanical behavior. Research at the Advanced Photon Source in Argonne National Laboratory couples experiments and thermal modeling aims to investigate the relations between the process, thermal history, microstructure and final mechanical behavior of additively manufactured materials. Some of the very first experiments of in-situ high-speed X-ray imaging of the powder deposition process at Argonne National Laboratory illuminate how processing conditions influence the build. Thermal monitoring, structural characterization and mechanical testing using X-ray computed tomography and micro-Laue diffraction show what mechanisms in the process lead to final part properties. Optimal process control requires thorough understanding of these process-structure-property relationships so that the same part could be built by various machines and systems. Future work includes manipulating laser-matter interactions with external magnetic fields, adaptive optics and reheating so that the complex phenomena in the process will not only be isolated and understood, but also used to build new functional materials.

Sarah Wolff is a Ph.D. candidate planning to defend her thesis this spring in mechanical engineering from the Advanced Manufacturing Processes Laboratory with Professors Jian Cao and Kornel Ehmann at Northwestern University. After completing a B.S. degree in environmental engineering at Northwestern and working in the aerospace industry, she transitioned to research sustainable manufacturing systems and later advanced processes. Sarah studies the underlying physics of laser-material interactions in both subtractive and additive processes and their influence on resulting microstructure and mechanical behavior. She is also building an open-architecture hybrid processing rapid prototyping machine in hopes to design new materials.