Formation of fine clusters in high-temperature oxidation of molten aluminum

Keehyun Kim*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

High-temperature oxidation of molten aluminum was investigated by high-resolution electron microscopes in order to determine the possibility of heterogeneous nucleation of aluminum grains on oxide for the grain refinement and structural uniformity of intensively melt-sheared aluminum alloys. High-resolution observations detect initial amorphous phase and gamma-alumina phase and show fine clusters with size of about 150 to 200 nm composed of extremely fine aluminum grains and gamma-alumina or amorphous aluminum oxide. Furthermore, high-resolution lattice images and diffraction patterns show no orientation relationship, although there is a specific orientation between gamma-alumina and aluminum along (111)[110] with high potency of heterogeneous nucleation. The volumetric shrinkage by the transformation of gamma- into alpha-alumina causes the surface oxide films to repeatedly rupture and leads to the creation of channels to the base melt surface for further oxidation of fresh metal. Based on the observations, the mechanism of high-temperature oxidation of molten aluminum and formation of the fine clusters as well as the possibility of the heterogeneous nucleation of aluminum grains are discussed.

Original languageEnglish
Pages (from-to)3650-3660
Number of pages11
JournalMetallurgical and Materials Transactions A
Volume45
Issue number8
DOIs
Publication statusPublished - 12 Apr 2014

Bibliographical note

Kim, K. Formation of Fine Clusters in High-Temperature Oxidation of Molten Aluminum. Metall and Mat Trans A 45, 3650–3660 (2014). https://doi.org/10.1007/s11661-014-2270-9

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys

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