Additive Manufacturing of Ceramic-based Materials: Process Development, Materials, Process Optimization and Applications: On-Demand Oral Presentations
Sponsored by: ACerS Engineering Ceramics Division, ACerS Basic Science Division, ACerS Manufacturing Division
Program Organizers: Xuan Song, University of Iowa; Lei Chen, University of Michigan-Dearborn; Xiangyang Dong, Arizona State University; Yiquan Wu, Alfred University; Paolo Colombo, University of Padova; Rajendra Bordia, Clemson University; Long-Qing Chen, The Pennsylvania State University
Friday 8:00 AM
October 22, 2021
Room: On-Demand Room 1
Location: MS&T On Demand
Session Chair: Xuan Song, University of Iowa
Invited
Towards Direct Additive Manufacturing of Ceramics by Selective Laser Flash Sintering: Desiderio Kovar1; 1University of Texas at Austin
Powder bed additive manufacturing (AM) utilizes a localized heat source such as a laser to selectively scan over regions of the bed that are to be sintered or melted. Direct powder bed AM does not require a polymer binder and is routine with metals but has proven more difficult to implement with ceramics because of their high homologous temperatures, slow sintering kinetics, and their susceptibility to thermal shock. The application of a large electric field while heating enables a phenomenon known as flash sintering at much higher rates and lower temperatures compared to conventional sintering. We have demonstrated that is possible to combine flash sintering with a scanning laser to locally selectively laser flash sinter (SLFS) a patterned layer of material. We suggest that it may be possible to utilize this approach to print directly AM 3D parts. Our experiences with YSZ, AlN, and LaCrO3 will be discussed.
Mesoscale Modeling of Sintering Kinetics in Direct Ink Write Additive Manufacturing: Fadi Abdeljawad1; 1Clemson University
Direct ink write (DIW) is a nascent additive manufacturing technique that is capable of rapidly fabricating arbitrary complex three-dimensional ceramic objects. DIW involves a sintering step that greatly influences many of the salient features of the printed object, such as internal porosity and grain microstructures. Herein, we present a mesoscopic modeling framework to examine solid-state sintering in DIW processes. The proposed modeling framework accounts for interface (i.e., free surfaces and grain boundaries) thermodynamics and captures various mass transport mechanisms. With the aid of several statistical (e.g., n-point statistics and chord length distributions) and topological (e.g., curvature) metrics, the role of particle size/distribution, equilibrium dihedral angles, and interfacial anisotropy in the microstructural evolution in filament-based DIW is explored and quantified. In broad terms, our modeling approach provides future avenues to explore the microstructural evolution and interfacial phenomena in DIW processes.
Structure and High Temperature Mechanics of Binder Jet 3D Printed Ceramic Compacts Treated with Reactive Precursors: Lynnora Grant1; C. Higgs III1; Zachary Cordero2; 1Rice University; 2Massachusetts Institute of Technology
The small initial interparticle contact area intrinsic to binder jet printed components makes them susceptible to creep at early stages of sintering, with ceramics being particularly susceptible to distortion when printed with traditional binders that burnout before the sintering temperature is reached. In our work, we address this challenge by introducing a reactive binder that reinforces interparticle contacts prior to sintering. By combining results from scanning electron microscopy and high temperature dilatometry experiments, we quantify the ways the reactive binder affects the microstructure, densification, and creep properties. Additionally, we show how the reactive binder treatment alters the high temperature sintering properties of the powder compact such as the uniaxial viscosity and the sintering stress. The contributions from this work provide insights for designing reactive binder and component systems robust against high temperature distortion.
Direct-writing by Micro Cold Spray of Yttria (Y2O3) Films: Aidan Moyers1; Michael Becker1; Desiderio Kovar1; 1The University of Texas at Austin
The micro cold spray process operates by accelerating aerosolized nanoparticles through a nozzle from atmospheric pressure (200-800 Torr) to mild vacuum (1-10 Torr). These nanoparticles, moving at 100-500 m/s, impact a substrate mounted on an x-y-z stage to allow for the direct-writing of conformal films on complex surfaces. Unlike cold spray, a similar process using larger particles and higher pressures, micro cold spray has the demonstrated capacity to deposit highly dense ceramic films through the mechanism of room temperature impact consolidation (RTIC). In this study, we performed molecular dynamics simulations on spherical yttria nanoparticles to investigate the conditions necessary to achieve RTIC by varying impact velocity, particle diameter, and crystallographic orientation. We then performed experiments to determine how processing variables such as deposition velocity affected the density of yttria films made with 300 nm particles.
Mechanical Properties and Ionic Conductivity of Li2O-Al2O3-TiO2-P2O5 Prepared Using Laser Powder Bed Fusion: Katherine Acord1; Alexander Dupuy1; Olivia Donaldson1; Xin Wang1; Timothy Rupert1; James Wu2; Qian Chen3; Julie Schoenung1; 1University of California, Irvine; 2NASA Glenn Research Center; 3Jet Propulsion Laboratory
Laser-based additive manufacturing offers a novel approach to single-step fabrication of functional ceramic materials without the use of inactive components (e.g., binders, slurries) employed in traditional ceramic additive manufacturing. We investigate the microstructure, mechanical properties, and ionic conductivity of the lithium ion battery solid electrolyte Li2O-Al2O3-TiO2-P2O5 (LATP) prepared using the laser-based additive manufacturing technique, laser powder bed fusion (L-PBF). The resulting bulk three-dimensional (3D) LATP samples exhibit high density (94-96%), structural stability and geometric complexity. The phase states and mechanical properties of the 3D LATP samples are comparable to conventionally sintered LATP samples. While the amount of secondary phase that forms during L-PBF is consistent with high temperature processing of LATP, the heterogenous size and distribution of secondary phase particles in 3D LATP samples influence the ionic conductivity. This study demonstrates that L-PBF is a promising method for the single-step fabrication of functional ceramic materials for lithium ion batteries.
Improving Ceramic Additive Manufacturing via Machine Learning-enabled Closed-Loop Control: Zhaolong Zhang1; Richard Sisson1; Jianyu Liang1; Zhaotong Yang1; 1Worcester Polytechnic Institute
Advanced ceramics are widely used in industries. To achieve the geometric complexity and desirable properties that are difficult to obtain by conventional manufacturing methods, ceramic additive manufacturing (AM) methods have been studied intensively in recent years. However, in-process control with feedback is not currently implemented in any commercially available ceramic three-dimensional (3D) printer. This study employed robocasting, a ceramic AM method, as an example of implementing an in-process control with a feedback loop in a ceramic AM process. In this research, the material parameters, process parameters, machine parameters, and their influences on quality parameters were investigated and identified. A database of the relationships among pressure, extrusion, and the quality of the printed green part was established. A Machine learning model was created based on the established database. Machine learning-enabled closed-loop control was integrated into the current robocasting process to improve the quality of the printed green parts.
Binder-free Additive Manufacturing of Ceramics Using Hydrothermal-assisted Jet Fusion: Fan Fei1; Levi Kirby1; Xuan Song1; 1University of Iowa
Ceramic additive manufacturing (AM) provides a freeform fabrication method for creating complex ceramic structures that have been extremely difficult to build by traditional manufacturing processes. However, ceramic AM processes typically require a high organic binder content to bond ceramic particles into pre-sintered solids (i.e., green bodies), which results in undesired residue and reduced density yielding unreliable properties in final products. In this research, we present a new ceramic AM process, named hydrothermal-assisted jet fusion (HJF), which utilizes a water-mediated hydrothermal mechanism to fuse particles, eliminating the use of organic binders in forming green bodies. A prototype system for the proposed HJF process is introduced. The effects of process parameters (such as layer thickness, external pressures, temperature) on the properties of achieved green parts were investigated. Experimental results indicate that with optimized process parameters, HJF can achieve 3D ceramic green parts with a high density up to 90%.
Effect of Particle Morphology and Green Part Density on Microstructure Evolution and Mechanical Properties of Sintered Alumina Fabricated via Ceramic Fused Filament Fabrication (CF3): Kameswara Pavan Kuma Ajjarapu1; Kavish Sudan1; Kunal Kate1; 1University of Louisville
In this work, Ceramic Fused Filament Fabrication (CF3) 3D printing process, that combines Fused Filament Fabrication (FFF) and sintering processes was used to fabricate dense alumina specimens. Spherical and irregular alumina powders were used to prepare highly-filled polymer feedstock filaments to determine how powder morphology and 3D printing parameters such as extrusion multiplier affect part density, powder packing and sintered microstructure. Green parts were printed with spherical and irregular alumina powder-filled filaments using an extrusion multiplier of 1.0. and 1.2 that corresponds to under and over-extrusion, resulting in a change in green density of 3D printed parts. All other 3D printing process parameters were kept constant. Further, the green parts were sintered at similar conditions to study the microstructural evolution and variation in mechanical properties with change in powder morphology and green part density.
3D Printed Ceramic Acoustic Liners for Aircraft Noise Reduction: David Nevarez-Saenz1; Ted Adler1; Wei Wei1; Bhisham Sharma1; 1Wichita State University
Aircraft noise is a significant constraint to increasing aviation capacity, efficiency, and flexibility. Current push towards the development of air taxis and supersonic aircrafts is bound to further exacerbate community noise issues. Overall aircraft noise is typically dominated by the sound emitted from turbofan engines. Traditionally, aircraft noise is reduced by a combination of passive acoustic liners installed in the engine nacelle. Recent research shows that insertion of acoustic liners directly over the engine rotors provides substantially better noise attenuation. However, current state-of-the-art liners are unable to withstand the harsh pressure and temperature environment in such locations. In this presentation, we discuss the feasibility of 3D printing ceramic liners for aircraft engine noise applications. The liners are printed using a material extrusion technique and their acoustic properties are characterized under normal incidence conditions. Our results suggest that 3D printed ceramic liners offer a feasible solution for improved aircraft noise reduction.
Micro-cold Spray: Influence of SiC Nanoparticle Impact Angle on Deformation Behavior: Derek Davies1; Michael Gammage2; Michael Becker1; John Keto1; Desiderio Kovar1; 1The University of Texas at Austin; 2CCDC DEVCOM Army Research Laboratory
The micro-cold spray (MCS) process produces thick films by accelerating aerosolized nanoparticles through a nozzle from near atmospheric pressure (300-760 Torr) to medium vacuum (1-3 Torr). By impacting these particles on a substrate translated orthogonal to the aerosol jet, patterned films are deposited. Compared to other particle deposition processes using high velocity impaction such as cold spray, MCS has demonstrated the unique capability of depositing high quality ceramic films at room temperature. Preliminary experiments suggested that impact angles other than normal relative to the substrate may improve deposition efficiency. We perform molecular dynamics simulations of single-nanoparticle impacts, varying the angle of impact, nanoparticle orientation, and velocity to determine the effect of these variables in combination on particle deformation. We compare these results to experimental MCS deposition of SiC, varying the average angle of impact by tilting the substrate.