The interfacial compounds and SEM fractography of squeeze-cast SiCp/6061 Al composites

The effects of the addition of silica binder during preform preparation on the development of interfacial compounds in squeeze-cast SiCp/6061 Al composites (containing silicon carbides with particle sizes of 85, 30 and 14 μm) were examined using energy dispersive spectroscopy (EDS) X-ray mapping, scanning electron microscopy (SEM) fractography and optical microscopy (OM). Various interfacial compounds, Al2O3, MgO and MgAl2O4, were observed. The effects of the various interfacial compounds on the SEM fractography and mechanical properties of the composites were investigated and a mechanism was suggested. The micromechanism of crack initiation, crack propagation and final fracture was discussed using SEM fractography and OM observations.