McCormack Lab

“The thermodynamic punishment must fit the structural crime.”

Research Vision:

   Humankind has an innate appetite for exploration1 2 3 , energy2 3 4 , and speed5 . These areas all require materials that operate in the most extreme environments, such as high temperatures (>1500 ˚C). While exploring the universe can be cold (~-270 ˚C in deep space), re-entry into a planet’s atmosphere can be hot (~1500 ˚C on Earth1 ). Thus, high temperature thermal barrier systems are required. Energy production through nuclear fission can reach temperatures of up to ~1700 ˚C and even higher for nuclear fussion4 , while nuclear thermal propulsion systems2  require temperatures up to ~2800 ˚C to provide thrust to propel next generation spacecrafts to Mars3  and beyond. When traveling at hypersonic speeds on Earth, leading edges can reach temperatures of ~2700 ˚C5  (at Mach 8). These are just some of the examples of where next generation high temperature material systems are required to propel civilization into the future.

   To effectively design high temperature material systems, one must have a clear understanding of their thermochemical and thermophysical properties, in addition to their atomic structure! The McCormack Laboratories central vision is to investigate and document material systems in extreme environments that enable next generation exploration, energy and high speed technologies

Research Scope:

   To develop and document complex oxide, carbide and nitride thermochemical and thermophysical properties under extreme conditions for next-generation space exploration materials. This leads to 4 key integrated fundamental research themes: (i) Material Synthesis, (ii) Crystallography, (iii) Calorimetry and (iv) CALPHAD. These themes are related to 2 key research initiatives: (i) Materials Design and (ii) Materials Discovery. These initiatives will work to support the key objective of materials to support space exploration, hypersonic platforms and nuclear fission/fusion reactors.

Research Initiatives:

   Materials Design is the focus of developing and perfecting material systems  for extreme environments, with a focus on ultra-high temperatures. Other extreme environments of interest include: high pressure, reactive plasma and harsh radiation. This includes the development of new experimental devices and techniques that push the limits of extreme environments. These material systems and experimental devices will be essential for engineering applications on earth and space exploration.

   Materials Discovery is the focus of identifying and understanding material systems in extreme environments with a focus on ultra-high temperatures. Other extreme environments of interest include: high pressure, reactive plasma and harsh radiation. The most extreme of these environments exist in our universe. Thus, we need to have an understanding of the chemical and physical properties of materials in these extreme environments as they could exist in deep space and they could assist us explore deep space.

Research Themes:

   New complex oxides, carbides, and nitrides will be synthesized using the steric entrapment method. The anisotropic thermophysical properties, viz., thermal expansion, compressibility and molar volume strains (related to the partial molar volume of mixing) will be measured using in-situ powder diffraction as a function of environment e.g. temperature, pressure etc. These thermophysical parameters will be documented for engineering applications and will be used to determine crystallographic orientation relations and lattice variant deformations (related to changes in shape and volume) of any observed transformations. This will be complemented with symmetry decomposition analyses to completely describe the symmetry relations between crystal structures. The phase transformation data will be used to assess if these materials can potentially be used as transformation toughening or shape memory ceramics. Thermochemical properties, viz., heat capacity, enthalpy of formation, the entropy of formation and enthalpy of mixing will be measured to determine the stability of the newly synthesized compounds. This information will influence the choice of future compositions for potential applications as high temperature, energy storage or structural materials. Finally, with the aid of the CALPHAD method, the complex oxide, carbide and nitride phase diagrams will be produced and optimized based on the experimentally measured thermophysical and thermochemical data.

   This work is a multidisciplinary endeavor, aimed at merging ideas from: (i) materials synthesis, (ii) crystallography (advanced symmetry and experimental analysis), (iii) calorimetry and (iv) computation (CALPHAD) to help tackle the space exploration challenge through the identification and fundamental understanding of new extreme environment for applications in energy storage, structural and shielding materials.

• 1 a b Glass DE. Ceramic Matrix Composite (CMC) Thermal Protection Systems (TPS) and Hot Structures for Hypersonic Vehicles. 2008. Available from: https://ntrs.nasa.gov/api/citations/20080017096/downloads/20080017096.pdf
• 2 a b c Memorandum on the National Strategy for Space Nuclear Power and Propulsion (Space Policy Directive-6) – The White House. 2021. Available from: https://trumpwhitehouse.archives.gov/presidential-actions/memorandum-national-strategy-space-nuclear-power-propulsion-space-policy-directive-6/
• 3 a b c Braun R, Myers R, Bragg-Sitton S, Cirtain J, Dodson T, Gallimore A, et al. Space Nuclear Propulsion for Human Mars Exploration. Washington, D.C.: National Academies Press; 2021. Available from: https://nap.nationalacademies.org/resource/25977/RH-snp.pdf
• 4 a b Fact Sheet: Developing a Bold Vision for Commercial Fusion Energy | The White House. 2022. Available from: https://www.whitehouse.gov/ostp/news-updates/2022/03/15/fact-sheet-developing-a-bold-vision-for-commercial-fusion-energy/
• 5 a b Dyatkin B. US hypersonics initiatives require accelerated efforts of the materials research community. MRS Bull. 2021; 46(3):201–3. Available from: https://link.springer.com/content/pdf/10.1557/s43577-021-00050-2.pdf