Interfacial reactions in Al-Mg (5083)/Al{sub 2}O{sub 3}p composites during fabrication and remelting

Journal Article · Sun Oct 01 04:00:00 EDT 1995 · Metallurgical Transactions, A

OSTI ID:131440

Zhong, W M; L`Esperance, G ^[1]; Suery, M ^[2]

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1. Ecole Polytechnique, Montreal, Quebec (Canada). Materials Engineering Dept.
2. National Polytechnique Institute, St. Martin d`Heres (France)

The interface reactions between {alpha}-Al{sub 2}O{sub 3} particles and 5083 Al-Mg alloys during fabrication by compocasting and subsequent remelting at 800 C for 30 minutes have been studied using analytical transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Experimental results show that MgO is the main reaction compound produced by the reaction 3Mg (1) + Al{sub 2}O{sub 3} (s) = 3MgO (s) + 2Al (l). The MgO crystals formed by interfacial reaction are very small (about 5 to 20 nm in diameter), and the reaction zone is about 50 to 80-nm wide for as-cast materials and about 100 to 150 nm after remelting. The reaction kinetics is controlled by seepage of Mg and release of Al (l) along the newly formed MgAl{sub 2}O{sub 4} or MgO grain boundaries. Because of the large volume expansion during the formation of MgO from the reaction between Mg (l) and Al{sub 2}O{sub 3} and because of the low diffusivity in MgO crystals, the reaction rate is very low.

• OSTI ID: 131440
• Journal Information: Metallurgical Transactions, A, Journal Name: Metallurgical Transactions, A Journal Issue: 10 Vol. 26; ISSN 0360-2133; ISSN MTTABN
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
40 CHEMISTRY
ALUMINIUM ALLOYS
ALUMINIUM OXIDES
CASTING
CHEMICAL REACTIONS
COMPOSITE MATERIALS
GRAIN BOUNDARIES
INTERFACES
LIQUID METALS
MAGNESIUM ALLOYS
REACTION KINETICS
SCANNING ELECTRON MICROSCOPY
TRANSMISSION ELECTRON MICROSCOPY