장근옥 교수

Second-phase particles are often employed to inhibit the grain growth of polycrystalline materials. We studied the interaction between a second-phase particle and a grain boundary using the phase-field method. In particular, we determined the magnitude of pinning force exerted by a particle on a grain boundary. We considered the effect of particle morphology by examining several particle shapes including spherical, ellipsoidal and cubic. The pinning forces computed from the phase-field were comp

Abstract We report an efficient phase field formalism to compute the stress distribution in polycrystalline materials with arbitrary elastic inhomogeneity and anisotropy The dependence of elastic stiffness tensor on grain orientation is taken into account, and the elastic equilibrium equation is solved using a spectral iterative perturbation method. We discuss its applications to computing residual stress distribution in systems containing arbitrarily shaped cavities and cracks (with zero elasti

We performed phase-field simulations to analyse the interaction of a migrating grain boundary with an evolving second-phase particle. It is found that depending on the difference between the interfacial energies of the particle–matrix interface for the two grain orientations involved and the driving force for grain boundary movement, particles with a particle size well above the critical limit can dissolve due to passage of the boundary.

Phase-field modeling of isotropic and anisotropic grain growth has been performed in 2D and 3D system. The multi order parameter grain growth model is adopted and OpenMP is implemented to enhance the computational efficiency. When the anisotropic grain growth phenomenon occurs, the misorientation distribution function of the low angle grain boundary is increased at the early stage and it converge to the certain value, 0.18 in 2D and 0.24 in 3D. The average numbers of faces of anisotropic grain g

In this study, the microstructural evolution of an Fe-Cr-Al system was simulated in two-dimensional (2D) and three-dimensional (3D) systems using the phase-field method. We investigated the effect of Al concentration on the microstructural evolution of the systems, with a focus on the nucleation and growth of the Cr-rich α′ phase. In addition, we quantitatively analyzed the mechanism of the effect of Al concentration on the microstructural characteristics of the 2D and 3D systems, such as the nu

The MacPherson–Srolovitz relation expresses the rate of volume change of a grain in a three-dimensional polycrystalline system in terms of microstructural parameters—the mean grain width and the triple line length—as well as isotropic values for the grain boundary mobility and energy. We introduce methods to accurately determine these microstructural measures for grain structures described by a voxel-based microstructure representation, such as those generated by phase-field simulations, Monte C

Two-dimensional phase-field simulations of void swelling in the Austenitic stainless steel were performed for irradiated materials. A numerical model was established for void swelling with an implementation of the elasticity effect, and we examined the roles of the applied stress and grain boundary sink strength and Frenkel defect recombination in determining the void swelling rate. The obtained results were compared with the existing experimental observations.

We analyzed and classified the grain structure in the vicinity of triple junctions during an ideal 2D grain growth process. We used the multi-order parameter phase-field grain-growth model to generate the grain structures and evaluated the distribution of the dihedral angles between the grain boundaries at triple junctions. The triple junctions were classified based on the microstructure represented by the sharp-interface representation, and the dihedral angles were estimated using the angle bet