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Oxidation mechanism of molten Al–5Mg–2Si–Mn alloy.
- Source :
- Journal of Materials Science; Sep2020, Vol. 55 Issue 26, p12554-12567, 14p, 2 Color Photographs, 2 Black and White Photographs, 2 Diagrams, 8 Charts, 4 Graphs
- Publication Year :
- 2020
-
Abstract
- The oxidation mechanism for the molten surface of Al–5Mg–2Si–Mn alloy was studied. The results show that the oxide layer contains MgO, Al<subscript>2</subscript>O<subscript>3</subscript>, MgAl<subscript>2</subscript>O<subscript>4</subscript>, BeO and SiO<subscript>2</subscript>, and it is composed of a composite inner layer (MgO/Al<subscript>2</subscript>O<subscript>3</subscript>/MgAl<subscript>2</subscript>O<subscript>4</subscript>/BeO/SiO<subscript>2</subscript>) and an outer layer of MgO. An oxidation mechanism was proposed to describe the four oxidation stages which included oxidation adsorption, accelerated oxidation, transitional oxidation and stable oxidation. The effects of oxidation time and oxidation temperature on the thickness of oxide layer were discussed. Thermodynamic calculations were used to confirm the feasibility of oxidation process, indicating that MgO was the most stable oxide in the experimental temperature range. Further, the stable regions of MgO and MgAl<subscript>2</subscript>O<subscript>4</subscript> as functions of magnesium content and oxidation temperature were calculated. In the stable oxidation stage, the diffusion activation energy of Mg atoms in MgO was fitted according to the outer layer thicknesses, and the kinetic equation of the outer layer thickness with the oxidation time and oxidation temperature was established. From the perspective of thermodynamics and kinetics, the oxidation products of the alloy during the melting process and the effects of oxidation time and temperature on the oxide layer were analyzed. [ABSTRACT FROM AUTHOR]
- Subjects :
- LIQUID alloys
OXIDATION
ACTIVATION energy
Subjects
Details
- Language :
- English
- ISSN :
- 00222461
- Volume :
- 55
- Issue :
- 26
- Database :
- Complementary Index
- Journal :
- Journal of Materials Science
- Publication Type :
- Academic Journal
- Accession number :
- 144203324
- Full Text :
- https://doi.org/10.1007/s10853-020-04874-2