A phase‐field model is applied to the simulation of microsegregation and microstructure formation during the solidification of multicomponent alloys. The results of the one‐dimensional numerical simulations show good agreement with those from the Clyne–Kurz equation. Phase‐field simulations of non‐isothermal dendrite growth are examined. Two‐dimensional computation results exhibit different dendrites in multicomponent alloys for different solute concentrations. Changes in carbon concentration appear to affect dendrite morphology. This is due to a larger concentration and a lower equilibrium partition coefficient for carbon. On the other hand, changes in phosphorus concentration affect the dendrites and interface velocity in multicomponent alloys during solidification when phosphorus content is increased from 10−3 mol% P. With additional manganese, the solidification kinetics slow down; dendrite morphology, however, is not affected. The potential of the phase‐field model for applications pertaining to solidification has been demonstrated through the simulations herein.

The mechanical properties and performance of metal materials depend on the intrinsic microstructures in these materials. In order to develop engineering materials as expected and to enable design with multifunctional materials, it is essential to predict the microstructural patterns, such as size, shape, and spacing of the dendritic structures observed in solidified metals. In materials science and related areas, the phase-field model is widely used as one of the powerful computational methods to simulate the formation of complex microstructures during solidification and phase transformation of metals and alloys. In the present study, the secondary-arm spacing for Fe-C binary alloys is numerically predicted using a phase-field model in a two-dimensional domain. When compared both with data by Ode et al. and with experimental data, the arm spacing predicted in the present work showed excellent agreement. Our estimates are performed at the late stage of growth. The change in arm spacing is examined both by changes of cooling rates and of local solidification time. A relation between material properties and model parameters is presented. Two-dimensional simulations produced dendrites that are similar to the ones found in experiments reported in the literature. Through numerical examples, applicability of the phase-field model to the problems of secondary-dendrite arm spacing in Fe-C alloys is demonstrated.

No abstract