Study on the interfacial reaction product in Gr/A1 composites

The interfacial reaction product Al4C3 in Gr/A1 composites was shown preferentially nucleated on graphite surface where attachments or amorphous carbon exist. No definite orientation relationship of Al4C3 with base graphite fiber was found in the present investigation. On the other hand, three different orientation relationships were established between Al4C3 and the surrounding aluminum matrix. The morphology of Al4C3, which was found to be controlled by processing conditions, is interpreted in terms of the extent and nature of two different growth control mechanisms. The concentration gradient of carbon in the aluminum matrix near graphite fiber surface was found. The carbon atoms for the growth of Al4C3 are considered to be supplied through the aluminum matrix along this concentration gradient.