Thermodynamics and Phase Diagrams
Thermodynamic descriptions have become available for a large number of alloy systems and allow the calculation of the phase diagrams of multicomponent alloys. This article begins with a discussion on three laws of thermodynamics: the Law of Conservation of Energy, the Second Law of Thermodynamics, and the Third Law of Thermodynamics. It informs that for transformations that occur at a constant temperature and pressure, the relative stability of the system is determined by its Gibbs free energy. The article describes the Gibbs free energy of a single-component unary system and the Gibbs free energy of a binary solution. It schematically illustrates the structure of a binary solid solution with interatomic bonds and shows how the equilibrium state of an alloy can be obtained from the free-energy curves at a given temperature. The article concludes with information on the construction of eutectic and binary phase diagrams from Gibbs free-energy curves.
Thermodynamics and Phase Diagrams, Alloy Phase Diagrams, Vol 3, ASM Handbook, Edited By H. Okamoto, M.E. Schlesinger, E.M. Mueller, ASM International, 2016, p 26–36, https://doi.org/10.31399/asm.hb.v03.a0006223
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