Spinodal decomposition in polycrystalline alloys

We have used a phase 'eld model (a continuum equivalent of the Potts model) for study-ing spinodal decomposition (SD) in polycrystalline alloys. We show that the evolution of the microstructure is governed largely by the di-erence in the grain boundary energies gb of A-rich and B-rich phases. When gb ¡ gb, the decomposition process is initiated with the formation of an layer (band) at the grain boundary, and of a layer on either side of it. In small grains, the entire grain is 'lled with two or three of these alternating and bands. In large grains, on the other hand, the microstructure exhibits a combination of GB-initiated bands and bicontinuous and regions in the grain interior produced by normal SD. During this decomposition process, grain growth is suppressed completely due to the pinning e-ect of the A-rich layer at the grain boundaries