SBIR Phase I: Continuous Fiber Ceramic Matrix Composite 3D Printing

This Small Business Innovation Research Phase I project will develop the process to 3D print continuous fiber reinforced ceramic matrix composite (CMC) components for turbine and combustion engines, hypersonic vehicles, and satellites. CMCs are currently a $2.5b market that is expected to triple over the next decade. The ability to produce CMCs with 3D printing will enable superior designs in current applications, as well as enabling their use in a greater number of components that are currently limited by the higher density and lower temperature capabilities of superalloys such as Inconel and Invar. Developing this manufacturing process will enable more basic materials research by serving as a lower cost testbed for new CMC compositions since a mold is not required and turnaround times are much faster. This will also allow engineers to develop more optimized systems with a faster design cycle. This capability will result in efficiency increases in turbine and combustion engines for substantial improvements in fuel efficiency, reducing costs and environmental impact. Finally, the ability to 3D print CMCs will vastly improve geometric complexity of high temperature components, which will enable the next generation of hypersonic vehicles, supporting national defense. The intellectual merit of this project is in establishing a novel manufacturing process for CMCs based on 3D printing. Melt infiltration is a low cost method to produce CMCs, which starts with a polymer matrix composite that is pyrolyzed, and then infiltrated with a molten metal. The matrix is usually a phenolic thermoset, but high temperature thermoplastics have recently been proven viable for simple coupons. This project will use 5-axis continuous fiber reinforced high temperature thermoplastic composites as green bodies. Since thermoplastics melt, support materials will be implemented during the pyrolysis step, which are effective in retaining part geometry. Additionally, a novel process of growing a boron nitride interphase layer on the fibers after pyrolysis instead of prior to forming the polymer composite will be implemented since tight corners during printing might damage an interphase layer. Finally, 3D printing with larger bend radius silicon carbide fibers instead of carbon fibers will be attempted. This project will demonstrate the effectiveness of this interphase with improved flexural strength and toughness, and the ability to form geometrically complex CMCs that are extremely difficult, if not impossible, to make with other methods. These two milestones will enable a path to begin developing parts for customers in commercial applications. 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.