Experimental Studies on the Mechanical Behaviour of LM25-SiCf-Interpenetrating Phase Composites Synthesized Using Gas Pressure Infiltration

Silicon carbide foams (SiC f ) are used as potential materials for heat shielding elements in the aerospace, automotive, and chemical industries due to their exceptional thermal stability, low density, and high hardness. However, the very low strength of SiC f limits its use for developing load-bearing structural components. Impregnating a suitable metal into the SiC f makes them suitable for high-strength applications. The processing route designated for impregnating the metal into the SiC f determines the strength of the resulting material. This article outlines the mechanical behaviour of the novel LM25 aluminium alloy-SiC f -based interpenetrating phase composites (IPCs) developed using the gas pressure infiltration technique. The LM25 alloy was infiltrated into SiC f with three different pore sizes, namely 10, 20, and 30 pores per inch (PPI). The macroscopic morphology of the IPCs revealed that a strong bond has been established between LM25 and SiC f . The compressive strengths of IPCs developed using 10, 20, and 30 PPI-SiC f were 97.5, 53.65, and 32.18 times higher than those of the respective SiC f . Similarly, the fracture strength and fracture toughness of the IPCs manufactured using 10, 20, and 30 PPI-SiC f were 7.44, 5.85, and 6.05 times better than those of the respective SiC f . Amongst the three variants of IPCs, the IPC developed using 10 PPI-SiC f possessed the highest values of compressive strength, fracture strength, and fracture toughness. However, the IPC developed using 30 PPI-SiC f exhibited superior resistance to indentation. Macro- and micro-structural analyses were conducted to establish the failure modes of the IPCs under both compression and flexure loads.