Estimation of the thermodynamic stability of amorphous alloys Fe‐Si‐B and Co‐Si‐B

Abstract

AbstractThe estimation of thermodynamic functions of crystallization of amorphous alloys was carried out using a two‐stage procedure. The main approximation for this consists in the consideration of amorphous alloys as a supercooled metastable liquid solution. The first stage describes the thermodynamic properties of the melts Co‐Si‐B and Fe‐Si‐B by means of the ideal association model. A method of mathematical optimization was used to get the most reliable model parameters. All experimental thermodynamic data (integral and partial enthalpies, entropies and chemical potentials received by different experimental methods) available in the literature for both the ternary system and all composed binary systems were taken into account for this purpose. The second stage of estimation consists in the extrapolation of the calculated temperature and concentration dependences of the thermodynamic functions of the melts to low temperatures, using known models for the heat capacities of undercooled melts, and their comparison with appropriate thermodynamic functions of crystalline phases. The estimated values for the enthalpy of crystallization of the Fe‐B, Co‐Si‐B and Fe‐Si‐B amorphous alloys are in good agreement with experimental data.