Effects of gravity on columnar dendritic growth of metallic alloys: flow pattern and mass transfer

• Published in: Journal of crystal growth 1998, Vol.183 (3), p.469-489
• Main Authors: Dupouy, M.D, Camel, D
• Format: Article
• Language: English
• Subjects: Applied sciences; Columnar dendritic solidification; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Growth from melts; zone melting and refining; Growth in microgravity environments; Macro-(meso)segregations; Materials science; Metals. Metallurgy; Methods of crystal growth; physics of crystal growth; Microgravity; Natural convection; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Physics; Scaling; Solidification
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/S0022-0248(97)00415-6

Simple rules are proposed for the prediction of segregation effects due to natural convection in the mushy zone during directional solidification in the columnar dendritic regime. The study is based on a scaling analysis of the mass and solute transport coupled with an interpretation of the results of previous experiments performed by the authors in different orientations relative to gravity and in microgravity. Natural flow effects in the mush are shown to be controlled by a unique dimensionless group and a method to build microstructure maps is proposed, which accounts for natural convection. Satisfactory agreement is found between the predicted scaling laws and the longitudinal macrosegregations measured in our experiments. The influence of natural convection on primary spacing will be considered in a forthcoming paper.