Free-energy calculation of precipitate nucleation in an Fe-Cu-Ni alloy

We extend our newly proposed calculation method of precipitate nucleation free energy to ternary systems. This method utilized first principles calculations for enthalpy change and interface energy, and the Bragg-Williams approximation for entropy loss from scattered atoms condensing into a cluster. The effect of Ni addition on copper precipitation in the Fc-Cu system was examined by this method. It was revealed that added Ni prefers segregation at the matrix/cluster interface, and reduces the activation energy barrier as well as the interface energy.