Calculation of the gamma/gamma' interface free energy in the Ni-Al system by the capillary fluctuation method

Monte Carlo computer simulations with an embedded-atom potential are applied to study coherent gamma/gamma' interfaces in the Ni-Al system. The (100) interface free energy has been extracted from the power spectrum of equilibrium shape fluctuations (capillary waves) and found to decrease with temperature from about 20 mJ/m2 at 550 K to about 10 mJ/m2 at 1200 K. These numbers are in reasonable agreement with existing experimental data. Strengths and disadvantages of the capillary wave method are discussed.