Jonathan Lee | 17-ERD-042
Laser powder bed fusion is a fabrication process in which sequential layers of metal powder are melted by a high-power laser to generate the desired part. However, these parts often suffer high failure rates due to the formation of defects or undesirable microstructure. Traditional process optimization methods are expensive and time-consuming. In this project, in situ, ultrafast, x-ray diagnostic approaches were applied to understand the dynamics of laser powder bed fusion additive manufacturing. The project realized unprecedented insight into sub-surface behaviors, including pore formation, cracking, and spatter generation during laser powder bed fusion, that ultimately influence part structure and composition. Importantly, the experimental outcomes were coupled to advanced multi-physics simulations, which enabled unparalleled understanding and validation of melt pool dynamics. The findings advanced our understanding of laser-based additive manufacturing of metals, and the implemented x-ray capabilities can be extended to a variety of ultrafast phenomena and processes.
The cutting-edge, in situ, capabilities for characterizing and understanding additive manufacturing processes generated in this project directly support Lawrence Livermore National Laboratory's core competency in advanced materials and manufacturing, and increase expertise in this research area, particularly priorities in materials design and manufacturing and the development of in situ diagnostics. Furthermore, the capabilities for validating state-of-the-art simulations (ALE3D) are anticipated to impact multiple programs and projects across the Laboratory, with an emphasis on those incorporating advanced manufacturing processes. The investment in designing and building new detector optics will be invaluable to all future Livermore research efforts that rely on the ultrafast detector array, both in terms of optimizing data quality and the efficient use of experimental beamtime at synchrotron sources. Investments in growing advanced manufacturing expertise support NNSA's stockpile stewardship mission and DOE's mission to strengthen technological innovation through advances in fundamental science.
Publications, Presentations, and Patents
Calta, N., et al. 2019. “Pressure dependence of the laser material interaction under high speed welding and additive manufacturing conditions probed by in situ X-ray imaging.” SFF Symposium, Austin, TX, August 2019. LLNL-PRES-786578
——— 2020a. “Pressure dependence of laser-material interactions under laser powder bed fusion conditions probed by in situ X-ray imaging.” Additive Manufacturing, 32, 101084. doi: 10.1016/j.addma.2020.101084. LLNL-JRNL-788222
——— 2020b. “The influence of laser modulation on melt pool behavior in laser powder bed fusion probed with in situ X-ray imaging.” TMS Annual Meeting, San Diego, CA, February 2020. LLNL-PRES-805465
Khairallah, S., et al. 2020. “Controlling interdependent meso-nanosecond dynamics and defect generation in metal 3D printing.” Science, 368, 660. LLNL-JRNL-774900
Martin, A., et al. 2018. “Investigation of laser-metal interaction using high-speed X-ray imaging. Oral Presentation.” SFF Symposium, Austin, TX, August 2018. LLNL-PRES-756607
——— 2019a. "Ultrafast dynamics of laser-metal interactions in additive manufacturing alloys captured by in situ X-ray imaging," Materials Today Advances, 1, 100002. doi: 10.1016/j.mtadv.2019.01.001. LLNL-JRNL-756599
——— 2019b. “Investigation of aluminum cerium alloy laser melting dynamics under additive manufacturing conditions.” SFF Symposium, Austin, TX, August 2019. LLNL-PRES-785437
McCall, S.K. 2019. “Materials Design for Advanced Manufacturing.” NASA Breakthrough Materials Workshop, Huntsville, AL, April 2019. LLNL-PRES-772619