Gradient, Large Scale Additively Manufactured Ceramic StructuresONR White Paper Tracking Number: 21-000000118
Abstract
Current approaches to ceramic additive manufacturing (AM) are capable of high resolution, small scale structures. Larger scale structures composed of neat or fiber-filled thermoplastics are achievable using material extrusion (MatEx) approaches. However, strategies for fabrication of larger scale ceramic structures do not currently exist due to physical limitations imposed by post-processing.We propose to address the knowledge gap that would enable larger scale ceramic components through printed gradient structures that take advantage of novel binder design, tailoring of particle size distributions, and tailored spatial variation of composition. The proposed concepts have the potential to transform ceramic AM by enabling the fabrication of structures with substantially larger dimensions, improving performance of those structures, and enabling new classes of gradient structures to be created.The proposed research is focused on material-processing relationships within ceramic-powder AM. Three primary aims will be pursued: 1.Spatially vary binder composition within ceramic AM to build mesoscale mass-transport networks. 2.Tailor binder-ceramic interfacial interactions to create self-assembling nanoscale mass-transport networks.3. Harness gradients in particle size distribution for directional capillarity to drive binder to the surface.Each aim is focused on understanding a specific aspect of the processing of additively manufactured ceramics, with the goal of enabling accelerated debinding for scalable gradient ceramic AM. Aim 1 focuses on fabricating integrated mesoscale mass transport networks during AM of green parts to facilitate the debinding process to produce brown parts. We proposeto address the rate-limiting step of diffusion of volatiles through the molten binder by locally patterning of two binder compositions. One binder decomposes first, resulting in an open porous microvascular network that dramatically reduces average volatile diffusion distances forthe remaining binder.In Aim 2, multicomponent binder chemistries will be used to achieve self-assembling networks that form co-continuous networks of a low temperature degrading polymer within a mechanically robust polymer-ceramic composite. Thisstructure will create nanoscale hollow percolated networks in brown parts, which will drastically accelerate debinding. Aim 3 focuses on investigating capillarity gradients created through spatially tailored particle size distributions for driving binder redistribution during binder removal post-processing. These capillarity gradients will drive binder redistribution toward the part surface,thereby reducing the volatilization distance into environment and accelerating the debinding.Combined, the research aims will provide new insights for AM of ceramics with substantially larger dimensions and broaden the range of materials systems that can be printed from being constrained to a single (static) composition to on-the-fly (dynamic) tailorability of feedstock ratios. The knowledge gained through the proposed research could be leveraged for fabrication of many novel structures, such as armor and shielding with gradient properties, which could simultaneously reduce weight and improve performance. Additionally, the knowledge gained from the proposed activities could be applied more broadly to advance other binder-based metal and ceramic processes or the fabrication of highly loaded polymer composites.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jun 09, 2021
- Source ID
- N000142112569
Entities
People
- Amy M Peterson
Organizations
- Office of Naval Research
- United States Navy
- University of Massachusetts