Thermodynamic investigation of the aluminum carbide formation in Al-SiC composite by image analysis

The changes in the chemistry and morphology within the interphase region of a pure-aluminum/?-SiC p metal matrix composite upon exposing the samples to exhaustive heat treatments have been studied by scanning electron microscope and by applying image analysis techniques (stereology) to optical microscope photographs of the composite cross-sections. Microstructural variations, such as the formation of small A1 4C 3 crystals at the interphase and the erosion of the reinforcement grains, were observed. The explanation and the consequences for these behaviors are discussed. Aluminum carbide formation is of interest for its degrading effect on the mechanical properties of metal matrix composites.