Additive Manufacturing of High and Ultra-high Temperature Ceramics and Composites: Processing, Characterization and Testing: New Methods and Characterization
Sponsored by: ACerS Young Professionals Network
Program Organizers: Corson Cramer, Oak Ridge National Laboratory; Lisa Rueschhoff, Air Force Research Laboratory; Greg Hilmas, Missouri University of Science and Technology
Wednesday 2:00 PM
October 12, 2022
Room: 306
Location: David L. Lawrence Convention Center
Session Chair: Lisa Rueschhoff, Air Force Research Laboratory
2:00 PM Invited
Heterogeneous Lattice Structure Ceramic-Refractory Metal Materials Created via Additive Manufacturing: David Mitchell1; Corson Cramer1; Trevor Aguirre1; Steven Bullock1; Christopher Ledford1; Michael Kirka1; Austin Schumacher1; 1Oak Ridge National Laboratory
Refractory metals have high melting temperatures, but also have very high densities. Ceramics have high sublimation temperatures, high temperature oxidation resistance and relatively low densities. Both types of materials demonstrate relatively brittle failure behavior. Continuous fiber ceramic matrix composites (CMCs) have demonstrated that composite microstructures can provide a material with a brittle reinforcing phase and a brittle matrix phase that exhibits damage tolerance and graceful failure behavior. However, continuous fiber CMCs are very labor intensive and expensive to produce, limiting their applicability in many applications. To develop an additively manufactured high temperature composite material, refractory metal-ceramic heterogeneous structures were created. This was accomplished by creating a tungsten lattice structure via an electron beam additive manufacturing process, then adding the silicon carbide or zirconium diboride ceramic matrix by a powder infiltration process. The resultant structures were analyzed to identify chemical and phase composition as well as microstructure.
2:30 PM Invited
Optimizing Functionally Graded ZrB2-Mo Components by Ceramic On-Demand Extrusion (CODE): Austin Martin1; Clare Sabata1; Jeremy Watts1; Gregory Hilmas1; Ming Leu1; Tieshu Huang2; 1Missouri University of Science and Technology; 2Kansas City National Security Campus, Honeywell Federal Manufacturing & Technologies
Functionally graded materials (FGMs) involve the spatial variation of chemical composition or structure to achieve an optimization of material properties. Ultra-high temperature ceramics (UHTCs) are classified as materials which have melting points above 3000°C, and although UHTCs can retain high strengths and oxidation resistance at high temperatures (>1500°C), these materials are typically brittle and therefore may benefit from underlying ductile or higher fracture toughness substructures. Molybdenum (Mo) alloys, such as Mo-Si-B or Ti-Zr-Mo (TZM), are high temperature (~1000°C), creep resistant alloys which have improved fracture toughness (RT ~10 MPa∙√m) or greater) compared to pure zirconium diboride (ZrB2). Using ceramic on-demand extrusion (CODE), eleven-layer ZrB2-Mo FGMs bars were produced with nominally 10% grading between layers. These baseline gradings warped an average of 20° after sintering due to a mismatch in sintering kinetics. Chemical and physical modifications to the ZrB2 and Mo pastes, respectively, were evaluated to alleviate the camber from co-firing.
3:00 PM Invited
Laser-induced Slip Casting for Additive Manufacturing of Large Ceramic Components: Shawn Allan1; Yannik Zieger2; Martin Schwentenwein2; Johannes Homa2; 1Lithoz America LLC; 2Lithoz GmbH
Additive manufacturing of advanced ceramics is steadily gaining importance for a wide variety of applications. Three common obstacles for ceramic AM are 1) long debinding times, 2) limitations to relatively small geometries, and 3) limited solutions for dark, non-oxide ultrahigh temperature ceramics (UHTCs). A novel aqueous-slurry based method, laser-induced slip casting (LIS), allows printing and subsequent sintering of large and bulky components. Via infrared lithographic exposure, thermal energy is generated that partially dries the suspensions and consolidates the structure with a high green density. The method is not dependent on the color or light-absorption of the ceramic powders, allowing dark materials such as carbides and other UHTCs to be processed. LIS has been applied to alumina, solid-state sintered silicon carbide, and silicon nitride (beta-sialon), yielding densities of approximately 99%. The resulting material strength is on par with conventional forming methods such as slip-cast or pressed ceramics.
3:30 PM Break
3:50 PM
In-Bath 3D Printing of Preceramic Polymers: Majid Minary1; 1Arizona State University
Preceramic polymer resins are attractive for the 3D printing of net-shaped ceramic components. Recently various processes have been demonstrated for 3D printing of polymer-derived ceramics (PDCs). Ultimately in these processes, the process outcomes strongly depend on the process parameters. In particular, for PDCs the ceramic density, and ceramic yield are affected by the catalyst concentration and cross-linking duration. In this work, we use thermal analysis and FTIR to quantify the interrelation of the process parameters on the process outcome for polysilazanes and demonstrate 3D printing of PDC components based on the best-identified process parameters. The results of this work can be used as guidelines for future additive manufacturing of PDCs.
4:10 PM
Micro and Nanostructured Compositing Approaches to Green Body Strengthening of Polymer-Derived UHTC: Justin Hendrix1; Matthew Laskoski1; 1Naval Research Lab
Additive manufacturing of Ultra High Temperature Ceramics (UHTC) provide a number of unique solutions in supporting high performance materials capabilities for armor and hypersonic engine applications. The advantage of 3D printing offers a distinct ability of producing complex parts with reduced configuration for machinability. As the architecture requirements become more stringent, parts become more challenging to produce, due to increasing size and higher resolution based on application. This suggest that the properties of the pre-sintered green body, play an enormous role in quality of the final part. In this work, we investigate a number of strengthening additives to improve the mechanical and structural properties of our preceramic polymer green bodies. Our previous work has shown that we can achieve high densification of our unique polymer based ceramic formulation. With green body strengthening, we will show that we may provide facile approaches to some of the challenges 3D printed ceramics face.
4:30 PM
Oxidation Behavior of Additively Manufactured SiC-SiOC Composites: Mackenzie Ridley1; Trevor Aguirre1; Corson Cramer1; 1Oak Ridge National Laboratory
Additively manufactured (AM) ceramics can support the development of components with complex geometries for a variety of high-temperature applications. In this work, silicon-based polymer infiltration and pyrolysis cycles were used to develop SiC-SiOC composites. The steam and air oxidation behaviors were studied up to 1500°C to determine the effectiveness of SiOC on oxidation resistance. Oxidation rates, reaction mechanisms, and effects of processing conditions on material performance will be discussed. This work is supported by the United States Department of Energy, Office of Energy Efficiency and Renewable Energy, Advanced Manufacturing Office.
4:50 PM
Structural Characterization of the 3D Printed Ceramic Composite Materials: Saja Al-ajrash; Charles Browning1; 1University of Dayton
Unique process that utilizes AM, preceramic polymer, and chopped carbon fibers precursor to fabricate SiC/C composites has been developed. The study has shown promising, cost-effective, and efficient routes to fabricate complex SiC/C composites using additive manufacturing. A key part of this effort was the mapping of the material’s microstructure through the composite's thickness. Microstructural features, in the pyrolyzed composites through the successive AM layers, such as defects, crystal size, and their distribution, interatomic spacing, and chemical bonds were investigated using HRSEM and HRTEM. Dense and nearly defect-free parts were observed. The CMC displayed three coexisting phases including SiC, SiOC, and C. TEM imaging and XRD showed well-defined SiC and turbostratic carbon features. The cross-sectional mapping of the printed-then-pyrolyzed structures has confirmed consistent structural and chemical features within the internal layers of the AM parts. Noteworthy however is that a crust-like area with high crystallinity has been observed in external layers.