Phase Field Modeling of Microstructural Evolution in Solids: Effect of Coupling among Different Extended Defects

Abstract

Microstructural evolution during phase transformation and plastic deformation is controlled by the coupling among different extended defects present simultaneously in crystalline solids under various processing and service conditions. Dislocations, stacking faults, homophase and heterophase interfaces, and precipitates are typical examples of these defects. Bombardment of crystalline solids by energetic particles will add additional defects such as vacancy/self-interstitial clusters and cascades. In this article, we introduce a general phase field formulation that allows for simultaneous treatment of these extended defects in a common framework. Using gradient thermodynamics of nonuniform systems and microelasticity theory of strain-carrying defects, the method describes naturally spatio-temporal evolution of arbitrary structural and compositional nonuniformities associated with various extended defects. Several examples are discussed, including effect of dislocation on spinodal decomposition and precipitation, effect of vacancy and interstitial discs on dislocation motion, and rafting of c¢ in Ni-base alloys that involves concurrent evolution of precipitate microstructure and dislocations.

Effect of dislocations on spinodal decomposition in Fe–Cr alloys

“…Recently, phase-field simulations have been conducted to study spinodal decomposition in alloys with dislocations [13][14][15] and to investigate dislocation formation and dislocation dynamics [16][17][18][19]. For instance, Léonard and Desai [13] conducted phasefield simulations of spinodal decomposition in an isotropic alloy with dislocations.…”

Elastic stress effects on microstructural instabilities

“…We have also come across several attempts towards extending the models to incorporate interfacial energy anisotropy and different aspects of plasticity; see for example the study on stressed incoherent solid-solid interfaces by Paret [284], effect of coupling of defects such as dislocations, coherent interfaces, vacancy and interstitial discs on microstructural evolution [285], spinodal phase separation induced by irradiation in the presence of dislocations [286], phase separation coupled with large elastic and large elasticplastic deformations during Lithiation in Li-ion battery electrodes [287,288],…”

Phase stability and defect structures in (Ti,Al)N hard coatings

“…In these studies, the strain effects generated by dislocations or other defects were ignored. Phase-field modelling of spinodal decomposition in alloys have recently accounted the formation and dynamics of dislocation [57][58][59]. Figure 3.3 shows the model result of the spinodal decomposition process for an alloy with an edge dislocation.…”