What is it about?

Metal additive manufacturing (AM) is a rapidly growing field, known for its flexibility in custom made designs using various material systems. However, there still exists a gap in understanding of the fundamental non-equilibrium processes which directly affects the microstructure and mechanical properties of the printed parts. Meanwhile, knowledge of conventional manufacturing is not directly transferable to understand the complex physics involved in metal AM. This work develops a small-scale prototype for metal AM and integrates it at a user facility, the Cornell High Energy Synchrotron Source (CHESS). The synchrotron source generates very high energy x-rays that could penetrate through our material systems and provide critical insights about the fundamental physics of the process. We explore the different modes of the metal AM process, including changing the laser beam profiles and powder delivery mechanisms. This helps us understand the variations that exist in different printers, ultimately affecting defect formation and microstructure of printed parts.

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Why is it important?

Understanding the fundamentals of metal AM process using synchrotron x-ray diffraction helps us see the materials’ thermomechanical changes in real time. We use these critical insights to design new material systems, which are defect free and have better mechanical properties. Use of x-rays enables us to penetrate optically opaque samples and probe the process at the sub-surface level. De-convolution of such a stochastic process is possible at unprecedented spatial and temporal resolutions, due to the state-of-the-art technology of very high energy x-rays coupled with fast detectors at synchrotron facilities.

Perspectives

Metal AM is widely used; however, the physics of the process is not well understood. High energy synchrotron facilities are state of the art tools to prob the complex dynamic of solidification during metal AM at high spatio-temporal resolutions. These complicated experiments are a multi-year initiative which involves design, assembly, integration and finally data analyses, to name a few. Most often, the analysis procedures are non-standard or novel. However, knowledge of changes down to the atomic scale in real time helps us gather high-fidelity data which could enhance our fundamental understanding of the process. Such datasets also act as ground truth for validation of various computational models. It could also give us new insights into novel mechanisms that occur during metal AM, and how it is different from conventional manufacturing techniques.

Adrita Dass
Cornell University

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This page is a summary of: Laser based directed energy deposition system for operando synchrotron x-ray experiments, Review of Scientific Instruments, July 2022, American Institute of Physics,
DOI: 10.1063/5.0081186.
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