Simulation of unidirectional solidification with a tilted crystalline axis

Abstract

Tilting of the crystal profile during directional solidification is studied numerically, when the crystalline axis is misoriented from the temperature gradient and the pulling direction. Only with the anisotropy in surface stiffness is the crystal shown to tilt to an angle smaller than the misorientation of the crystalline axis . The angle approaches on increasing the pulling velocity V, as is often observed in experiments. The V dependence of the tilting thus does not necessarily mean that the tilting is caused by the kinetic effect. With ϭ45°we observe tip splitting and double fingers, a constituent of the compact seaweed pattern. ͓S1063-651X͑96͒05907-7͔

Phase-field simulation of tilted growth of dendritic arrays during directional solidification

“…A basic understanding for non-axially oriented directional solidification is that the growth direction of dendritic arrays rotates from the thermal gradient direction to the orientation of the preferred crystalline as the pulling velocity or the primary spacing is increased. There is no doubt that the tilted growth results from the competition between the two directions [11][12][13][14][15][16][17][18][19][20]. Previous experimental and numerical studies [12][13][14] indicate that the anisotropy of the surface tension and the solute interaction of neighboring ones should be responsible for the growth direction selection, whereas the amplitude of the thermal gradient has no significant influence on that.…”

“…There is no doubt that the tilted growth results from the competition between the two directions [11][12][13][14][15][16][17][18][19][20]. Previous experimental and numerical studies [12][13][14] indicate that the anisotropy of the surface tension and the solute interaction of neighboring ones should be responsible for the growth direction selection, whereas the amplitude of the thermal gradient has no significant influence on that. Through analyzing a large amount of data from the experiments of thin samples of a succinonitrile-based alloy, Deschamps et al [17,18] proposed a rotation law for the tilted growth of dendritic arrays in the full range of the misorientation angle.…”

Dendrite growth directions and morphology in the directional solidification of anisotropic materials

“…[3][4][5][6] On the numerical side also, only a couple of simulations were achieved prior to the development of phase-fi eld simulation. 6,12 Altogether, one then lacks experimental and numerical data points to quantitatively study this issue.…”

“…When these directions differ, the growth direction of dendrites is found to rotate from the thermal gradient direction to a preferred crystalline orientation as the growth velocity is increased. [1][2][3][4][5][6][7][8][9][10][11][12][13] In addition to this, one notices dramatic changes of dendrite morphology, especially dendrite asymmetry and the development of secondary branches in between dendrites, that have implications on the resulting microsegregation process.…”

Morphological evolution of the solid-liquid interface near grain boundaries during directional solidification

“…Another interesting feature of the solidification process is the growth direction of a microstructure [16][17][18][19][20]. It is well known that the growth directions of cells are approximately parallel to the thermal gradient direction, deflecting from the crystalline orientation <100> for a SCN-based alloy.…”