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


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.


Metal Matrix Orientation Relationship Silicon Particle Primary Aluminium Fine Silicon 
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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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