A Phase Field Study of Spinodal Decomposition in Systems with Variable Mobility

Saini, Rahul Kumar and Bhattacharya, Saswata (2018) A Phase Field Study of Spinodal Decomposition in Systems with Variable Mobility. Masters thesis, Indian Institute of Technology Hyderabad.

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Abstract

The present work is directed towards the study of the spinodal decomposition in the binary alloys with constant mobility and concentration-dependent degenerate mobility. We solved the Cahn-Hilliard diffusion equation using the semi-implicit Fourier spectral method. This method is more efficient and faster than the forward Euler finite-difference method. We compared the kinetics of binary alloys with constant mobility and variable mobility. The free energy functional of the system depends on composition and composition gradients. The bulk-free energy is due to nearest neighbor bonds while the gradient energy is due to interfacial energy and given by the square of the gradient of the composition field. We have simulated at three different initial compositions in 2D and one composition in 3D. A dynamical system characterized using the structure function, the scaling function, the pair correlation function and the length scale. These functions calculated after selected time steps taking averages over three simulations using a different set of random numbers for each composition. We have evolved the microstructure for each composition.

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