The Computer Simulation Of The Fe-Mo Binary Alloy Spinodal Decomposition With Microscopic Phase-Field Model

Simple spinodal decomposition in binary system was simulated using microscropic phase-field method, based on which the spinodal decomposition under elastic energy was simulated combining with the microscopic elasticity theory and microscopic diffusion equation. The model can be applied to the whole precipitation process and composition range. Any prior assumptions on the new phase structure or transformation path was unnecessary, the possible nonequilibrium phases and atomic clustering could be described automatically, the relevant information of time of the precipitation structures were obtained.and then the microstructure evolution induced by spinodal decomposition during aging process was characterized. Analyse the spinodal decomposition at the early stages and the coarsening.In the case of simple spinodal decomposition, both the decomposing and coarsening speeds were depending on the initial composition (c0) and reached their maximum at c0 = 0.5. When elastic energy was considered during spinodal decomposition:when the elastic strain energy was 0, spherical-shaped precipitates or flocculent structure distributed randomly with isotropic morphology. With the elastic strain energy, the arrangement orientation increases, elliptical structures, wattle structures and quasi-periodical structures etc were formed with anisotropic morphology.The coherent spinodal line of Fe-Mo binary alloy was obtained, the topmost temperature was 770℃in which spinodal decomposition can happen at C_Mo=0.5 and the topmost temperature was 320℃at C_Mo=0.1. The results was basically accord with the theory. At the same temperature, the speed of spinodal decomposition was quicker and quicker while component was close to C_Mo=0.5 and the speed was quicker at lower temperature at same component.