Crystallography and refining mechanism of (Ti, B)-contained salts in pure aluminum

It is shown from experiment that the pure B contained salt exhibits little refining effect, while the pure Ti contained salt, especially the salt containing 5Ti/1B, shows obvious refining effect on the pure aluminum. Crystallographic study indicates that Al 3Ti particle is a more suitable nucleation...

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Bibliographic Details
Published in:Transactions of Nonferrous Metals Society of China 2008-08, Vol.18 (4), p.836-841
Main Author: ZHANG, Heng-hua
Format: Article
Language:English
Subjects:
crystallography
microstructure
pure aluminum
refining mechanism
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Summary:It is shown from experiment that the pure B contained salt exhibits little refining effect, while the pure Ti contained salt, especially the salt containing 5Ti/1B, shows obvious refining effect on the pure aluminum. Crystallographic study indicates that Al 3Ti particle is a more suitable nucleation site for the aluminum matrix than (Ti, Al)B 2 type particles (TiB 2, AlB 2 and (Ti, Al)B 2), because there exist more coherent planes with aluminum matrix in the former. Thermodynamics estimation, X-ray diffraction (XRD) and SEM detection show that the refining mechanism of (Ti, B)-contained refiners is mainly contributed to the heterogeneous nuclei of fine Al 3Ti particles dispersed in the melting, which comes from the reaction between the Ti and aluminum. (Al, Ti)B 2 type particle shows little or no direct refining effect, but it will reduce the size of Al 3Ti since the Al 3Ti nucleates and grows along the (Al, Ti)B 2 type particle interface.
ISSN:1003-6326
DOI:10.1016/S1003-6326(08)60145-4