Phase-field simulation of effect of lateral constrains on dendritic spacing change

The mechanical properties of materials are strongly dependent upon their microstructures, and the lateral constrains in presence of melt have a significantly effect on the microstructure evolution. A non-isothermal phase-field model for pure metal was implemented to simulate the microstructure evolution in the presence of lateral constrains of different shapes during the solidification of pure Ni, in order to study the effect of lateral constrains on the dendritic spacing changes caused by these lateral constrains. The results indicate that lateral constrains have a direct influence on the dendrite development, and the lateral constrains of different shapes can lead to different influences on the dendrite arm spacing changes. The constrains of triangle with sharp corner at the bottom has the most significant influence on the dendrite spacing changes, and rectangle and triangular constrains with its sharp corner above show a controlling effect on the dendrite arm spacing, that is, the dendrite growth of different primary arm spacings has the same developing manner with these two kinds of lateral constrains, the new developing dendrite arm spacing is determined by the shape of constrains, and has less relationship with its primary arm spacing. When the lateral constrain of trapezoid is introduced, the dendrite arm spacing can be determined by changing the size of the hemline of constrains. Therefore, the lateral constrains in the solidification process can significantly change the dendrite arm spacing.