On primary dendritic spacing during unidirectional solidification

Journal Article · Sun Sep 01 04:00:00 EDT 1996 · Acta Materialia

DOI:https://doi.org/10.1016/1359-6454(96)00018-3· OSTI ID:389820

Ding, G L; Huang, W D; Huang, X; Lin, X; Zhou, Y H ^[1]

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1. Northwestern Polytechnical Univ., Xi`an (China). State Key Lab. of Solidification Processing

In-situ observations of directionally solidifying interface of typical transparent model alloys, succinonitrile-ethanol and succinonitrile-acetone, have been performed on a Hunt-Jackson type temperature gradient stage and a Bridgman apparatus, respectively. Experimental results show that there exists a wide allowable range of primary spacings for both the two-dimensional and the three-dimensional dendritic arrays under a given growth condition. The upper and lower limits of the allowable range are very sharp at the same current growth condition, while the average primary spacing is remarkably related to the history of variation of both temperature gradient and growth velocity. The upper limit, {lambda}{sub max}, and the lower one, {lambda}{sub min}, of the allowable range as a function of growth velocity, V, obtained from the experiments of step-increment and step-decrement in growth velocity, can be generally expressed as {lambda}{sub max} = AV{sup {minus}b}, {lambda}{sub min} = cV{sup {minus}d}, where a, b, c and d are constants for given alloy and temperature gradient. The lower limit obtained experimentally by the authors is compared with that calculated theoretically with the Hunt-Lu model and the Warren-Langer model; it shows an excellent fit between experimental results and the Hunt-Lu model, and good agreement between experimental results and the Warren-Langer model at the high growth velocity.

• OSTI ID: 389820
• Journal Information: Acta Materialia, Journal Name: Acta Materialia Journal Issue: 9 Vol. 44; ISSN 1359-6454; ISSN ACMAFD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ACETONE
ALLOYS
BRIDGMAN METHOD
DENDRITES
ETHANOL
INTERFACES
MATHEMATICAL MODELS
NITRILES
SIMULATION
SOLIDIFICATION
SUCCINIC ACID
TEMPERATURE GRADIENTS
VELOCITY