Modification of the interface in SiC/Al composites

Methodologies both to avoid the formation of Al₄C₃ and to tailor the interfacial structures in a SiC/2014 Al composite were demonstrated. Modification of the interfacial structures in the SiC/2014 Al composite was made by forming SiO₂ layers on the surfaces of SiC via passive oxidation at elevated temperatures. In the 2014 Al composite reinforced with the oxidized SiC, MgAl₂O₄ and Si crystals were observed to be present at the interfacial region as a result of the reaction between the SiO₂ layer and the matrix. On the other hand, in the case of the 2014 Al composite reinforced with unoxidized SiC, SiC was found to react with the Al matrix to form both Al₄C₃ and Si. Qualitative measurements of the interfacial bonding strength were carried out on composites having various types of interfaces and thicknesses. Detailed interfacial structures and phase identifications, which were examined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), were presented.