Characterizing the Dynamics of the Laser Metal Deposition Additive Manufacturing Process

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Laser metal deposition (LMD), also called blown-powder direct laser deposition, is an important additive manufacturing technique for producing customized and functionally-graded parts for a variety of applications in the aerospace, automobile, biomedical and defense industries. Even though investment in current research in, and development of, LMD technology is growing quickly, significant challenges remain in production of metal parts with repeatable and predictable properties. This research project will explore in detail the processes of LMD; identify the sources of defect formation and part quality uncertainties; and lay the groundwork for creating repeatable and predictable properties in LMD manufacturing. The research project includes rich educational and outreach components, which will provide undergraduate and graduate students with exposure to additive manufacturing. An e-Learning module will be developed to disseminate the data and knowledge obtained by this project. The knowledge allow modelers to improve and validate models and simulation tools. This research will therefore advance competitiveness of U.S. industry, supporting domestic economic growth and national defense.The overall objective of this research is to characterize the dynamics of the LMD process beneath the surface of the melt pool at a high spatial and temporal resolution to understand the fundamental mechanisms of the LMD process. The specific objectives of this research project are to characterize: (1) the dynamics of melt pool formation and evolution, and melt flow within the melt pool; (2) the dynamics of pore formation and evolution; (3) the material mixing behavior during blowing powders with different compositions; and (4) the dynamics of the solidification process during LMD. The research approach uses in-situ high-speed high-energy and high-resolution synchrotron x-ray imaging and high-speed high-energy x-ray diffraction. This project will significantly advance the fundamental understanding of the LMD additive manufacturing process. The dynamics of melt pool, pore, material mixing, and solidification during the LMD process will be revealed. The fundamental mechanisms of melting, mixing, defects formation, and microstructure evolution during LMD process will be unraveled.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.