Eur. Phys. J. B (2022) 95: 51
https://doi.org/10.1140/epjb/s10051-022-00310-3

Regular Article - Statistical and Nonlinear Physics

Pressure-dependent phase diagrams and elastic properties of Ti_xCo_1−x: first-principle and Monte-Carlo calculations

¹ Department of Physics, College of Science, Taibah University (Yanbu branch), Al-Madinah, Kingdom of Saudi Arabia
² Department of Physics, College of Science, Islamic University, Al-Madinah, Kingdom of Saudi Arabia

^c mkhalfalla@taibahu.edu.sa

Received: 24 October 2021
Accepted: 28 February 2022
Published online: 16 March 2022

Abstract

We investigated (using Monte-Carlo and first-principle calculations) the effect of pressure on the phase diagrams and elastic properties of Ti_xCo_1−x (a superalloy candidate). USPEX (Universal Structure Predictor: Evolutionary Xtallography) generated the parent structures required by the Monte-Carlo calculation of the phase diagrams at different pressures (0–100 GPa). The calculated space groups and formation energies qualitatively conform with the experiment within the Co-rich region at 0 GPa. We observed pressure-induced structural transition from the cubic to the tetragonal phase around 80 GPa, comparable with the reported 66 GPa transition pressure. Widening of the phases’ miscibility gaps with the pressure was regarded as an indication for the increase of the melting points. Interestingly, the dependence of the calculated chemical potential on pressure and temperature was consistent with the thermodynamic activity for the binary solid mixture. Finally, enhancement of the elastic properties of the parent structures was observed with increasing pressure.