Modeling Convection during Monotectic Growth
Abstract
In monotectic growth, two phases, a solid phase, α, and a liquid phase, L_2, grow cooperatively from a single liquid phase L_1. The interface separating the parent liquid L1 phase from the daughter liquid L2 phase is then subject to the well-known instabilities that can occur in systems with a fluid-fluid interface between immiscible liquids.The thermal and solutal gradients inherent to the solidification process lead to the possibility of surface-tension-driven flows at the L_1--L2 interface. There are also additional considerations that arise due to the nature of the thermodynamics and processing conditions. Since phase equilibrium is maintained at the L_1--L2 interface, the temperature, compositions, pressures, and interface curvature are related by thermodynamic constraints that do not apply in a simple mechanical system. In addition, as growth occurs, material penetrates the L_1--L2 interface, which is not a material surface which is simply advected by the flow. We have developed models for the solute field in the L2 phase, and performed numerical computations to estimate the magnitude of the flow strength due to Marangoni forces. A comparison of the results of these calculations with experiments on the inter-rod spacing in the aluminum-indium system suggest that there may be an additional convective transport mechanism for solute.
- Publication:
-
APS Division of Fluid Dynamics Meeting Abstracts
- Pub Date:
- November 1999
- Bibcode:
- 1999APS..DFD..JH04M