| About this Abstract |
| Meeting |
MS&T21: Materials Science & Technology
|
| Symposium
|
Materials vs Minerals: Bridging the Gap between Materials Science and Earth and Planetary Science
|
| Presentation Title |
Modeling Thermodynamics of Condensation of Fe-Ti-bearing Byroxenes Relevant to the Early Solar System |
| Author(s) |
Venkateswara Manga, Thomas Zega |
| On-Site Speaker (Planned) |
Venkateswara Manga |
| Abstract Scope |
Pyroxene, Ca(Mg,Ti,Fe)(Al,Si)2O6, is an important mineral group. In primitive meteorites it occurs as a constituent of major petrographic components such as chondrules and calcium-and-aluminum-rich inclusions, the latter which are reported to be the first solids to have condensed in our early solar system. Knowledge of pyroxene thermodynamics is therefore important to understanding the conditions (e.g. T and P) under which such phases condensed in the high-temperature region of the solar nebula. To this end we report first-principles driven thermodynamic modeling of the pyroxene within the CALPHAD framework. The enthalpies and entropies of mixing of the solid solutions at different compositions are calculated from first-principles calculations of special-quasirandom-structures. The condensation temperatures of the solution phase at different pressures of the nebular gas and the temperature-dependent evolution of its crystal chemistry are predicted. We will discuss the implications of the model predictions to the microstructural analysis of CAIs and their thermodynamic origins. |