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Journal of Materials Science

, Volume 26, Issue 8, pp 2245–2254 | Cite as

Microstructural studies of aluminium-silicon alloy reinforced with alumina fibres

  • Ming Yang
  • V. D. Scott
Papers

Abstract

The microstructure of an alumina fibre reinforced Al-7wt% Si alloy has been investigated. It was shown that the Al-Si eutectic structure which characterized this alloy was markedly changed by the presence of the fibres, with coarsening of silicon particles and a reduction in primary aluminium grain size. The coarse silicon particles exhibited twinning but no orientation relationship with the aluminium. Fine silicon precipitates were also present and these had a cube-cube orientation relationship with the aluminium lattice. Lath-like intermetallics, FeSiAl5 and FeSi2Al4 with monoclinic and tetragonal structures, were identified which existed in equilibrium and had the epitaxial relationship (001)mono//(001)tet and [100]mono//[100]tet. The iron was a contaminant introduced in the course of composite fabrication.

Dislocations were a common feature of the aluminium matrix, with a typical density of ∼4×107mm−2. Nevertheless, dislocation hardening of the metal matrix was not detected. No evidence of Mg2Si precipitates in the metal matrix was found, but the small addition (0.2wt%) of magnesium to the alloy was discovered to segregate at the fibre-aluminium interface. This segregation was believed to result in improved wettability of the two constituents, encouraging the formation of a strong fibre-matrix bond, and producing desirable properties of the composite in the transverse direction.

Keywords

Metal Matrix Orientation Relationship Silicon Particle Primary Aluminium Fine Silicon 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Chapman and Hall Ltd. 1991

Authors and Affiliations

  • Ming Yang
    • 1
  • V. D. Scott
    • 1
  1. 1.School of Materials ScienceUniversity of BathClaverton DownUK

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