Gravitational influence on the microstructure of directionally solidified monotectic and eutectic alloys

I. Aoi, Makoto Yoshida, S. Murao, H. Nakae

Research output: Chapter in Book/Report/Conference proceedingChapter

Abstract

In order to study the influence of gravity on the microstructure of directionally solidified Al-In monotectic alloy, Ag-Si and Al-Si eutectic alloys, both the downward (direction of gravity) and upward (opposite to direction of gravity) unidirectional solidifications were carried out. In the case of the downward U.D.S. by the current Bridgman method, the molten alloy must be confined between the crucible and a solid. This causes a shrinkage cavity at the solid/liquid interface during solidification. In this study, to avoid this `cavity formation', a zone-melting technique was used. The results are summarized as follows. (1) Regarding the unidirectional solidifications of Al-In alloy, the monotectic In(L 2) phase grows continuously in both growth directions. However, the morphology in the downward U.D.S. shows a tendency to form a so-called `banded structure.' (2) In the case of the upward U.D.S. of the Ag-Si alloy, the eutectic silicon phase grows continuously and its morphology shows the typical faceted/non-faceted eutectic structure. On the other hand, in the case of the downward U.D.S., the eutectic silicon phase grows discontinuously and disperses in the α-Ag phase with a diameter of several micrometers. This is caused by the large difference in specific density between the silver and silicon phases. (3) The eutectic silicon phase of the Al-Si alloy grows continuously regardless of the growth direction. There is no morphological difference between the upward and the downward U.D.S. specimens.

Original languageEnglish
Title of host publicationMaterials Science Forum
PublisherTrans Tech Publ
Pages259-264
Number of pages6
Volume329
Publication statusPublished - 2000
Externally publishedYes
EventProceedings of the 1999 3rd International Conference on Solidification and Gravity - Miskolc, Hung
Duration: 1999 Apr 251999 Apr 28

Other

OtherProceedings of the 1999 3rd International Conference on Solidification and Gravity
CityMiskolc, Hung
Period99/4/2599/4/28

Fingerprint

Eutectics
Silicon
Microstructure
Solidification
Gravitation
Zone melting
Crystal growth from melt
Crucibles
Silver
Density (specific gravity)
Molten materials
Direction compound
Liquids

ASJC Scopus subject areas

  • Materials Science(all)

Cite this

Aoi, I., Yoshida, M., Murao, S., & Nakae, H. (2000). Gravitational influence on the microstructure of directionally solidified monotectic and eutectic alloys. In Materials Science Forum (Vol. 329, pp. 259-264). Trans Tech Publ.

Gravitational influence on the microstructure of directionally solidified monotectic and eutectic alloys. / Aoi, I.; Yoshida, Makoto; Murao, S.; Nakae, H.

Materials Science Forum. Vol. 329 Trans Tech Publ, 2000. p. 259-264.

Research output: Chapter in Book/Report/Conference proceedingChapter

Aoi, I, Yoshida, M, Murao, S & Nakae, H 2000, Gravitational influence on the microstructure of directionally solidified monotectic and eutectic alloys. in Materials Science Forum. vol. 329, Trans Tech Publ, pp. 259-264, Proceedings of the 1999 3rd International Conference on Solidification and Gravity, Miskolc, Hung, 99/4/25.
Aoi I, Yoshida M, Murao S, Nakae H. Gravitational influence on the microstructure of directionally solidified monotectic and eutectic alloys. In Materials Science Forum. Vol. 329. Trans Tech Publ. 2000. p. 259-264
Aoi, I. ; Yoshida, Makoto ; Murao, S. ; Nakae, H. / Gravitational influence on the microstructure of directionally solidified monotectic and eutectic alloys. Materials Science Forum. Vol. 329 Trans Tech Publ, 2000. pp. 259-264
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