A theory for dendritic growth of needle shaped crystals growing in supercooled pure melts and dilute alloys is proposed. This theory predicts the growth velocity and tip radii as functions of supercooling and alloy concentrations without introduction of additional conditions such as marginal stability. A key ingredient of the theory is introducing the effect of the interfacial energy anisotropy. Deviation of the shape of the dendrite from a paraboloid of revolution is permitted, consistent with a small interfacial energy anisotropy. The radius of curvature and the growth rate as functions of melt supercooling and alloy concentrations are determined in terms of the anisotropy, and are compared with experimental results. The predictions are in agreement with the experimental results, especially at large supercoolings. The deviation at lower supercoolings can be attributed to the neglect of natural convection in the present theory.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Inorganic Chemistry
- Materials Chemistry