Multi-Scale Porous Ultra High Temperature Ceramics
Final rept. 28 Mar 2013-27 Sep 2014
MELBOURNE UNIV PARKVILLE (AUSTRALIA)
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This report summarizes the main outcomes of our research funded by the AOARD to develop multi-scale porosity Ultra High Temperature Ceramic materials. We have optimized the processing conditions to prepare zirconium diboride ZrB2 and titanium diboride TiB2 porous materials with up to 92 porosity by four different techniques replica, particle stabilized foams, ice templating freeze casting and partial sintering. The pore morphology closed-bubble-like porosity, open interconnected or lamellar porosity and pore size from 1 to 500 um can be fined tuned by optimizing the processing conditions. Selected conditions for each of these routes were used to explore the thermal conductivity and mechanical properties of the materials as a function of the porosity, pore size, shape and morphology. X-Ray Tomography was used to study their 3D microstructure. These 3D microstructure captured with the tomography was used to produce virtual microstructures for prediction of the materials thermal and elastic properties. The Lattice Monte Carlo LMC approach was used to predict the materials thermal properties and the Finite Element Analysis FEA was used to predict the materials elastic properties. The modelling helped to understand the role of the porous material microstructural features such as the pore size, amount of porosity and pore shape. The approach can be extended to predict and evaluate the performance of these porous materials under extreme conditions, such as during hypersonic flights.
- Ceramics, Refractories and Glass