Mechanical properties and hardness gradation of Al/Al2O3 composite bodies obtained by reaction between SiO2 and molten Al

Noboru Yoshikawa, Yoshiyuki Watanabe, Seiji Sugawara, Shoji Taniguchi, Atsushi Kikuchi

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4 Citations (Scopus)


It is known that silica (SiO2) is converted into Al/Al2O3 composite body, according to the following reaction: 3SiO2(S)+4Al(l)=2Al2O3(s)+3Si(in Al) In this study, composite bodies were fabricated at different reaction temperatures and their mechanical properties were investigated. The composite bodies fabricated below 1273 K had high hardness and revealed a brittle nature. On the other hand, in the composite bodies fabricated above 1273 K, hardness decreased and ductility increased a little. It is possible that plastic deformation occurs in the widened Al part in the coarse composite structures, and this is related with the decrease in hardness. The gradation of hardness in the composite bodies was attempted by changing the reaction temperature. A silica rod was dipped into a molten Al bath at 1073 K, and the temperature was increased to 1373 K. There was no hardness variation along the radial direction in the cross section of the rod. When the reaction temperature was decreased form 1373 K to 1073 K, hardness was graded to be larger in the core area. However, the maximum hardness was not high as expected from the non-graded (reacted at constant temperature of 1073 K) specimens. By lowering the reaction temperature together with moving the specimen (gradual plunging), hardness gradation along the longitudinal direction was accomplished and large hardness difference existed. It was found that the cause for high hardness was related with the formation of nano-scaled composite microstructures containing low temperature (θ, γ)-Al2O3 phases.

Original languageEnglish
Pages (from-to)1006-1012
Number of pages7
JournalNippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals
Issue number11
Publication statusPublished - 1998


  • Composite
  • Compressive strength
  • Hardness gradation
  • Material
  • Microstructure
  • Reaction temperature

ASJC Scopus subject areas

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


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