| About this Abstract |
| Meeting |
MS&T21: Materials Science & Technology
|
| Symposium
|
Thermodynamics of Materials in Extreme Environments
|
| Presentation Title |
Directions of Zero Thermal Expansion in Anisotropic Oxides |
| Author(s) |
Scott J. Mccormack, William Wheeler, Benjamin Hulbert, Waltraud Kriven |
| On-Site Speaker (Planned) |
Scott J. Mccormack |
| Abstract Scope |
Oxide materials often have anisotropic crystal structures, which can result in direction-dependent material properties. While they typically have positive coefficients of thermal expansion, it has been observed that some oxide materials can have directions of negative thermal expansion over certain temperature ranges. Such materials, having both positive and negative coefficients of thermal expansion must also have particular directions in which the thermal expansion is zero. In-situ high-temperature X-ray diffraction was used to track directions of zero thermal expansion in HfTiO4 from room temperature to melting. These experiments were performed using a Quadrupole Lamp Furnace (QLF) (T~ 200 - 2000 ˚C) at the National Synchrotron Light Source II (NSLS II) and a Conical Nozzle Levitator system equipped with CO2 laser (CNL) (T ~ 700 - 3400 ˚C) at the Advanced Photon Source (APS). These results have important implications for the design of directional near-zero thermal expansion materials. |