Kinetics of Phase Separation in Ternary Alloys

The asymptotic behavior of the minor element, Z, in a X-Y-Z ternary alloy associated with decomposition of the major element, Y, is classified into three groups according to the sign of the second derivative of the chemical free energy f_I with respect to the concentration of Y, c_Y and the concentration of Z, c_Z: In the case of ∂²f _I/∂c_Y∂c_Z > 0, the value of c _Z along the trajectory of the peak top of the Y decreases with time. When ∂²f_I/∂c_Z∂c_Y < 0 at 0 ≤ t < ∞, peaks of c_Z formed at peak tops of Y. The amplitudes of these peaks increase with time. If ∂²f _I/∂c_Y∂c_Z < 0 at 0 ≤ t < t₀ and ∂²f_I/∂c_Y∂ c_Z > 0 at t₀ < t < ∞, bifurcation of peaks occurs at the later stage.