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Journal of Materials Science

, Volume 26, Issue 13, pp 3565–3574 | Cite as

Development of solidification microstructures in a fibre reinforced alloy

  • Q. F. Li
  • D. G. McCartney
  • A. M. Walker
Papers

Abstract

The solidification behaviour of a fibre reinforced Al-6 wt% Cu alloy, containing 30 vol% of 3 μm diameter, semi-continuous, aligned alumina fibres has been studied. Results are presented to show the influence of fibres on the microstructural development of and microsegregation in the matrix during freezing. The effect of total solidification time, θt, on solidification behaviour was examined for 1<θt<520 S. By using interrupted solidification experiments microstructural development was studied in detail. It was found that α-Al begins to grow within interfibre regions, and grows towards the Al2O3 fibres, avoiding them where possible. Consequently fibres are located in the last regions to solidify. When θt>10 s the final microstructure is non-dendritic, and CuAl2 is located predominantly at the fibre-matrix interface. When θt ≃ 1 s it was observed that the final microstructure is dendritic with a periodic segregation pattern, and the CuAl2 is more dispersed. The matrix composition becomes more uniform, and the minimum matrix composition rises as θt increases. The growth and microsegregation are analysed and discussed using simple semi-analytical models. The implications are that fibres significantly influence solidification behaviour if λfs<1, where λf is the average interfibre spacing and λs the secondary dendrite arm spacing which would develop in the unreinforced alloy.

Keywords

Final Microstructure Solidification Behaviour Matrix Composition Solidification Microstructure Unreinforced Alloy 
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

  • Q. F. Li
    • 1
  • D. G. McCartney
    • 1
  • A. M. Walker
    • 2
  1. 1.Department of Materials Science and EngineeringUniversity of LiverpoolLiverpoolUK
  2. 2.ICI Advanced MaterialsThe Heath, RuncornUK

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