Interfaces of SiC fibres and Al-5% Mg developed under systematically varied processing conditions

• Published in: Composites. Part A, Applied science and manufacturing Applied science and manufacturing, 1996, Vol.27 (9), p.703-708
• Main Authors: Long, S., Flower, H.M.
• Format: Article
• Language: English
• Subjects: Applied sciences; Cross-disciplinary physics: materials science; rheology; Dispersion-, fiber-, and platelet-reinforced metal-based composites; Exact sciences and technology; fibre; interfacial reactions; Materials science; Materials synthesis; materials processing; matrix interface; Metals. Metallurgy; Physics; processing conditions; SiC/Al composites
• ISSN: 1359-835X; 1878-5840
• DOI: 10.1016/1359-835X(96)84044-9

In the present work, attention has been focused on the processing-dependent nature of the interface of SiC fibre-reinforced A1 matrix composites fabricated by pressurized liquid metal infiltration. To determine the effect of variation of the processing parameters on the interface formation. Tyranno continuous SiC fibres have been infiltrated with Al-5% Mg melt under a range of melt superheat and infiltration pressure conditions. During processing the major processing parameters of the pressurized infiltration were precisely monitored. Analytical transmission electron microscopy of the obtained interfaces was employed to study the nature and extent of the interfacial reactions. Oxygen pre-existing in the fibres results in the formation of an interfacial oxide layer. The chemical reaction between SiC and Al occurs by Al penetration, in situ SiC decomposition and Al4C3 formation. Surplus C and the reduced Si diffuse into the interfacial matrix, resulting in the formation of interfacial Si and/or Mg2Si and interfacial Al4C3 protruding into the matrix Mg in the melt preferentially penetrates into the fibres but does not cause any observable variation in the fibre structure. Increases in melt superheat and infiltration pressure intensify the interfacial reactions. It is also found that the extent of the interfacial reactions and interfacial binding can be significantly altered by the geometrical location of the interface in question.