# Three Phase Ternary Spinodal

A small fluctuation in an symmetric alloy $c_{A}=c_{B}=c_{C}=\frac{1}{3}$ decomposes into a an A-rich phase, B-rich phase and a C-rich phase.

simulations from phasefield modelling

A small fluctuation in an symmetric alloy $c_{A}=c_{B}=c_{C}=\frac{1}{3}$ decomposes into a an A-rich phase, B-rich phase and a C-rich phase.

For the same time, increasing $\kappa$ results in a smoother profile.

Symmetric alloys form bicontinous microstructures. This can be seen on increasing the average composition of the allow from $x_B=0.35$ through $x_B=0.5$

In binary systems, symmetric alloys ($x_B = 0.5$) form biconinous microstructures (CH5 and CL5). Anisotropy is incorporated by modifiying the fourth rank tensor term in the Cahn-Hilliard formulation. The higher anisotropy case is CH5 and lower one is CL5.

An off-symmetric alloy ($x_B$=0.3) will not form bicontinous microstructures (above). The effect of high anisotropy is captured in CH3 while that for lower anisotropy is seen in CL3.

In a ternary system, for a fixed $\chi_{BC}=4.0$, the ratio $\frac{\chi_{AB}}{\chi_{AC}}$ is increased from 1 to 15. The change in the miscibility gap is shown here. ($\chi_{ij}$ is the effective interaction energy between $i$ and $j$)