A front-tracking model to predict solidification macrostructures and columnar to equiaxed transitions in alloy castings

S. McFadden, D. J. Browne

Research output: Contribution to journalArticle

49 Citations (Scopus)

Abstract

The solidified grain structure (macrostructure) of castings is predicted by process simulation using a newly extended front-tracking technique which models the growth of solid dendritic fronts through undercooled liquid during metallic alloy solidification. Such fronts are either constrained, as is the case with directed columnar growth from mould walls, or unconstrained, as is the case for multiple equiaxed growth from individual nucleating particles distributed throughout the liquid. Non-linear latent heat evolution is treated by incorporating the Scheil equation. Thermal conductivity changes with the solid fraction. A log-normal distribution of activation undercooling to initiate free growth from equiaxed nuclei is used, and the routines to deal with such growth followed by impingement of dendritic grains upon one another are verified by comparison with the results of analytical studies of simplified systems. The extensions to the model enable the predictions of equiaxed grain structure and, importantly, the columnar to equiaxed transition in inoculated alloy castings. The model is validated via comparison with experimental results. The front-tracking method is proposed as a suitable formulation for modelling alloy castings that solidify with a dendritic structure, either columnar, equiaxed, or both.

LanguageEnglish
Pages1397-1416
Number of pages20
JournalApplied Mathematical Modelling
Volume33
Issue number3
DOIs
Publication statusPublished - 1 Mar 2009

Fingerprint

Front Tracking
Solidification
Casting
Predict
Crystal microstructure
Liquid
Undercooling
Model
Log Normal Distribution
Latent heat
Process Simulation
Liquids
Normal distribution
Thermal Conductivity
Nucleus
Activation
Thermal conductivity
Heat
Chemical activation
Castings

Keywords

  • Dendritic growth
  • Front-tracking
  • Nucleation
  • Solidification

Cite this

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A front-tracking model to predict solidification macrostructures and columnar to equiaxed transitions in alloy castings. / McFadden, S.; Browne, D. J.

In: Applied Mathematical Modelling, Vol. 33, No. 3, 01.03.2009, p. 1397-1416.

Research output: Contribution to journalArticle

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