INTERFACE CHARACTERIZATION OF AN SIC PARTICULATE 6061 ALUMINUM-ALLOY COMPOSITE

In this paper electron microscope examination of the interface of an S iC particulate reinforced 6061 aluminium composite produced by a powde r metallurgy process is presented. Conventional transmission electron microscopy (TEM) revealed a faceted interface between the SiC particul ate and the aluminium matrix. It is postulated that the faceted interf ace is the result of the dissolution of the SiC particle by the liquid metal during the transient liquid sintering stage. It is concluded th at this faceted interface provides very strong bonding at the interfac e and this is further evidenced by fractographic results. Energy dispe rsive X-ray spectroscopy (EDX) and electron energy loss spectroscopy ( EELS) were used to identify the intermetallic compounds such as Mg2Si and FeSiAl5, some of which are found at the SiC/matrix interface. Init ial results suggest that these intermetallic particles have a detrimen tal effect as they cause early debonding at the interface. No Al4C3 pa rticles were observed. An X-ray diffraction technique was also used to confirm that no Al4C3 was formed during the sintering process.