Article ID Journal Published Year Pages File Type
1560146 Computational Materials Science 2015 9 Pages PDF
Abstract

•A phase-field model of MoSi2/NbSi2 lamellar silicide with elastic inhomogeneity is developed.•Microstructural formation and interface segregation are examined with the model.•Lamellar structure cannot be formed when elastic strain energy only is included.•A lamellar structure forms when anisotropic interfacial energy is considered.•Elastic inhomogeneity affects neither the microstructure nor the interfacial segregation.

We developed a phase-field model of C11b-MoSi2/C40-NbSi2 duplex silicide incorporating elastic inhomogeneity, and simulated microstructure formation and interface segregation. We examined the effect of elastic inhomogeneity on the morphology, volume fraction of the C11b-precipitate, stress distribution, and solute partitioning. In the simulations, parameters evaluated by first-principles calculation are used for the experimentally unknown parameters. The lamellar structure was not formed in the case incorporating the elastic strain energy only and ignoring the anisotropy of the interfacial energy. When the anisotropy of the interfacial energy was taken into account, the lamellar structure was formed parallel to (0 0 0 1)C40 as observed in the experiment. It was also found that the elastic strain energy changes the equilibrium concentrations by >0.2 at%, but the difference between the equilibrium concentrations in homogeneous and inhomogeneous systems was <0.1 at%. The interfacial segregation was also hardly affected by the elastic inhomogeneity. These results confirm that elastic inhomogeneity can be neglected in the simulation of MoSi2/NbSi2 lamellar silicide.

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Related Topics
Physical Sciences and Engineering Engineering Computational Mechanics
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