Theoretical Study on One-Dimensional Solidification of Binary Alloy
Date Issued
2007
Date
2007
Author(s)
Lien, Chun-Kuang
DOI
zh-TW
Abstract
The present study aimed at investigating theoretically the one-dimensioned solidification of alloy, emphasizing on the segregation, multiple-solution phenomenon, and instability due to the kinetic effect, boundary condition of a finite domain, and the density-difference induced convection.
The one-dimensioned solidification of alloy in an infinite domain possesses similarity solutions without segregation. Only dynamic instability instead of morphological instability can happen. However, when the kinetic effect is considered, there exist no similarity solutions anymore. Segregation becomes possible, but only exists in small time with small amount. For finite-domain solidification, the boundary effect makes the similarity solutions become invalid and the segregation more obvious.
When multiple solutions become possible, the solidification is the preferred mode. The other two modes of melting are only the mathematically possible solutions of coupling when the solute diffusivity is much smaller than the thermal diffusivity and the solidification front stays in thermal equilibrium. The density-difference induced convection does not change much the one-dimensional solidification phenomenon: similarity solutions still exist without segregation; only dynamic instability instead morphological instability can happen.
Subjects
合金
固化
數值方法
動態效應
多重根
alloy
solidification
numerical method
kinetic effect
multiple solutions
Type
thesis
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