ERI: Making High-Temperature Alloyed Components by Combining Additive Manufacturing and Spark Plasma Sintering: Enabling Shape Complexity and Predicting Microstructures

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This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).Spark plasma sintering is a well-known manufacturing technology, in which pressurizing and rapid heating are simultaneously applied to achieve particle-to-solid consolidation with a low level of defects even for high-temperature metals, such as tungsten alloys. Despite significant interest in this technology, it has been, however, limited to simple-shaped components (i.e., in cylindrical forms). On the other hand, though additive manufacturing has empowered the design freedom, ideal for making parts of sophisticated geometry, fabrications of high temperature alloys have not been reliably successful. In this project, a combination of additive manufacturing, such as binder jetting, and spark plasma sintering will be employed to overcome such limitations. The studied technology integration represents a novel and promising approach to produce complex-shaped components, made of high-temperature alloys, in an efficient and cost-effective manner, and yet, ensure the quality in part dimensions as well as microstructures. Moreover, the project will explore new possibilities for the investigation into the fundamentals of the field-assisted sintering processes. In addition, the project will contribute to the education, outreach and retaining of undergraduate and graduate students from minorities and to engaging high school students with hands-on experiences with high-end technologies such as additive manufacturing and spark plasma sintering via the collaboration with industry partners involved, e.g., California Nanotechnologies.The overall goal of this project is to understand and develop the net-shaping capability of the spark plasma sintering technology to produce complex-shaped parts, such as helical bevel gears, made of material systems difficult to be fabricated using either traditional or additive manufacturing. The project will address this challenge through the “controllable interface” concept, which combines the additive manufacturing capability to produce complex shapes with the full consolidation potential of the spark plasma sintering. The controllable interface is represented by a three-dimensionally printed deformable volume of a sacrificial material introduced inside common spark plasma sintering tooling. To achieve the desired design of the controllable interface, comprehensive modeling of the spark plasma sintering process will be researched. The intricate nature of the starting porous assembly involved in this combined technology requires extending the current powder sintering modeling framework to better understand thermal and non-thermal nonequilibrium phenomena in spark plasma sintering to predict the final processing outcomes in terms of the microstructure and geometry of end products.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.