Aluminium carbide formation in interpenetrating graphite/aluminium composites

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2007-03, Vol.448 (1), p.1-6
• Main Authors: Etter, T., Schulz, P., Weber, M., Metz, J., Wimmler, M., Löffler, J.F., Uggowitzer, P.J.
• Format: Article
• Language: English
• Subjects: Aluminium carbide; Applied sciences; Elasticity. Plasticity; Exact sciences and technology; Gas pressure infiltration; Graphite; Interpenetrating phase composites; Liquid metal infiltration; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Powder metallurgy. Composite materials; Production techniques; X-ray diffraction
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2006.11.088

We have produced interpenetrating graphite/aluminium composites by gas pressure infiltration of aluminium alloys with varying silicon content into porous graphite preforms. Infiltration experiments at 750 °C have shown that a silicon content of up to 18 wt.% can reduce the formation of aluminium carbide but cannot completely deter it. Optical and scanning electron microscopy revealed numerous lath-like interfacial aluminium carbide crystals in the μm regime which, however, did not affect the flexural strength of our composites. Severe aluminium carbide degradation was observed within a few days on composites exposed to ambient conditions. Carbide-free composites were produced by reducing the infiltration temperature to 670 °C for the eutectic alloy.