Comments on undercooling effects in microsegregation modelling
- General Motors Research and Development Center, Warren, MI (United States). Metallurgy Dept.
Kraft, Roosz, and Rettenmayr have recently incorporated several theoretical models for dendritic growth into a numerical model for predicting the microsegregation behavior in binary alloys; see also the recent review by Battle. More specifically, Kraft et al. have included the models developed by Burden and Hunt, and Laxmanan, into their calculations of microsegregation behavior. The main purpose of this article is (i) to clarify certain points made by Kraft et al. with respect to the Lmin model, i.e., the model developed by Laxmanan which invokes the minimum undercooling (MU) principle for tip radius and spacings selection, and (ii) to discuss the significance of some of the assumptions made in various growth models to solve the diffusion problem. The diffusion field surrounding the tips of a growing dendritic or cellular array, or even a single isolated dendrite, is quite complex, and the full significance of the various approximations made to characterize these fields, and develop predictive mathematical relations, have not yet been fully appreciated. Likewise, the MU principle is often confused with what appears superficially, and mathematically, to be an identical growth principle, viz. the maximum velocity (MV) principle that has been employed for dendrites growing freely into an initially undercooled melt.
- OSTI ID:
- 464807
- Journal Information:
- Scripta Materialia, Journal Name: Scripta Materialia Journal Issue: 6 Vol. 36; ISSN 1359-6462; ISSN SCMAF7
- Country of Publication:
- United States
- Language:
- English
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