| About this Abstract |
| Meeting |
MS&T22: Materials Science & Technology
|
| Symposium
|
High Temperature Oxidation of Metals and Ceramics
|
| Presentation Title |
Thermal Expansion Analysis of Mixed and High Entropy Rare Earth Disilicates via Synchrotron X-ray Scattering |
| Author(s) |
Alejandro Salanova, Ian Brummel, Elizabeth Opila, Jon Ihlefeld |
| On-Site Speaker (Planned) |
Alejandro Salanova |
| Abstract Scope |
Robust thermal/environmental barrier coatings (T/EBCs) can be developed using entropic stabilization at high temperatures. In this work, the anisotropic thermal expansion behavior of mixed rare earth (RE) and high entropy (HE) disilicate powders will be presented. Through rule of mixtures, combining RE cations resulted in stabilized phases not readily formed in individual compounds. The phase of these mixtures proved stable, as distinguishable by in-lab X-ray diffraction from room temperature to 1200 °C. Lattice parameters and thermal expansion were then determined using synchrotron radiation, showing the direction of maximum thermal expansion varies with temperature. The shifts correspond to changes in eigenvectors with respect to temperature, manifesting as distinctions in shear components in the tensor and lattice parameter changes. The shifts were pronounced in Yb-containing compositions, but less so in compositions devoid of Yb. Initial efforts to elucidate the phenomena leading to these behaviors using pair distribution function analysis will be presented. |