Applied thermodynamics: Grain boundary segregation

Abstract

Chemical composition of interfaces-free surfaces and grain boundaries-is generally described by the Langmuir-McLean segregation isotherm controlled by Gibbs energy of segregation. Various components of the Gibbs energy of segregation, the standard and the excess ones as well as other thermodynamic state functions-enthalpy, entropy and volume-of interfacial segregation are derived and their physical meaning is elucidated. The importance of the thermodynamic state functions of grain boundary segregation, their dependence on volume solid solubility, mutual solute-solute interaction and pressure effect in ferrous alloys is demonstrated. © 2014 by the authors.