Abstract:Electron microscope examination of the microstructure, interface and fracture surface of SiC particulate reinforced 2024 aluminium alloy composites produced by powder mixing and semi-solid extrusion process was presented. The microstructure of SiC_p/2024 composites fabricated by the present method is characterized by uniformly distributed SiC particulates in well-densified matrix. Conventional transmission electron microscopy(TEM) reveals the interface between the SiC particulates and the aluminium matrix. It is shown that this interface provides very strong bonding which is further evidenced by the fractographic results, and that there is no apparent chemical reaction. Examination of the fracture surface indicates that the bonding strength between the SiC particulates and the aluminium alloy matrix is stronger than that of the matrix. The dimples and tearing edges on the fracture surface of composites are obviously observed.

Key words:  metal-matrix composites; interface; microstructure; semi-solid extrusion