Phase Diagrams

· Combining the entropy and enthalpy curves gives three possible forms of the Gibbs function curves.

From: Brophy, Rose, and Wulff.,
"Thermodynamics of Structure," Wiley (1964)

· For the negative (a) and ideal deviation (b) enthalpy curves, the Gibbs function has a minimum for intermediate alloy compositions.
· For the positive deviation, the alloy can show two minima in the Gibbs function as a function of composition. This material will separate into two solutions of compositions X₁ and X₂ that have the same chemical potential.