Modeling the feeding of aluminum alloy castings

Conference · Tue Oct 01 04:00:00 EDT 1996

OSTI ID:372049

Ahmed, A; Apelian, D ^[1]; Dahle, A K; Arnberg, L ^[2]

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1. Worcester Polytechnic Inst., MA (United States). Aluminum Casting Research Lab.
2. Norwegian Inst. of Tech., Trondheim (Norway)

Aluminum alloy castings, in general solidify with the growth of equiaxed dendrites followed by eutectic precipitation. Dendritic growth and eutectic precipitation are influenced by a complex combination of macroscopic transport phenomena and microscopic solidification kinetics. The feeding process, i.e. the shrinkage driven material transport and solidification mechanism is influenced by the state of the mushy zone--the local solid fraction and its distribution within the zone. Consequently, the mushy zone must be divided into several distinct regions in order to successfully model the solidification and feeding process. These regions have different mechanical and solidification characteristics and are governed by differing transport mechanisms and solidification kinetics. A mathematical model for solidification and feeding is developed coupling the macroscopic transport process with microscopic solidification kinetics considering the various regions of the mushy zone. An outline of the numerical solution of the coupled system is presented. Upon implementation, this model will predict several important solidification variables such as dendrite coherence, grain size distribution and porosity. The phenomenology of feeding during solidification and the framework of the model are reviewed.

• OSTI ID: 372049
• Report Number(s): CONF-960202--; ISBN 0-87339-312-0
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM BASE ALLOYS
CASTING
CHEMICAL COMPOSITION
COOLING
DEFECTS
DENDRITES
EUTECTICS
GRAIN REFINEMENT
HYDROGEN
KINETICS
MASS TRANSFER
MATHEMATICAL MODELS
POROSITY
PRECIPITATION
SHRINKAGE
SOLIDIFICATION
TEMPERATURE GRADIENTS