Microstructural and mechanical characterization of SiC/Al interpenetrating phase composites fabricated by pressure-assisted infiltration

Interpenetrating phase composites (IPCs) are a class of advanced materials that integrate multiple phases, such as continuous ceramic and metallic networks, offering an alternative to conventional particle- or fiber-reinforced composites. In this study, SiC/Al IPCs are fabricated via gas-pressure infiltration using commercial SiC foams with a constant relative density (∼20%) and varying pore sizes of 10 and 20 pores per inch (ppi). The infiltration process of Al 6082 was carried out at 1100 °C under vacuum, followed by purging with pressurized inert gas to enable metal infiltration. Although microstructural observations suggested good interfacial bonding and crack-free interfaces, X-ray computed tomography images revealed significant internal porosity within the aluminium phase. Under compression, both IPC variants exhibited a similar strength-to-weight ratio of approximately 30 MPa cm³/g. In contrast, three-point bending tests showed that the 20 ppi IPC exhibited approximately twice the flexural strength of the 10 ppi IPC, while the 10 ppi IPC demonstrated the highest energy absorption efficiency.