Prediction of Thermodynamic Properties of Mo-Si-B Alloys from First-Principles Calculations

Many technological applications such as heat treatment processes and their computational modeling and simulation require knowledge of the thermodynamic properties of the phases involved. Depending on the alloy system, experimental methods to obtain high-accuracy values especially for specific heat capacity of ultra-high-melting alloys will require high-temperature equipment, which is expensive and restricted in terms of the maximum temperature. We present a method for obtaining these values from first-principles (density functional theory) calculations and compare this method to experimental data of Mo-based alloys. The ab initio approach is based on the computation of elastic properties, which are then used to fit a Birch–Murnaghan equation of state to solve the Debye model. Experimental values are obtained by differential scanning calorimetry of single-phase and three-phase samples, from which individual phase properties are reconstructed using a phase mixing approach. It can be concluded that all methods employed agree within reasonable limits of accuracy, showing the validity of the first-principles approach.