Abstract:Al2024/SiC functionally graded materials (FGMs) with different numbers of graded layers and different amounts of SiC were fabricated successfully by powder metallurgy method and hot pressing process. The effects of increasing SiC content and number of layers of Al2024/SiC FGMs on the microstructure and mechanical properties of the composite were investigated. X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX) analyses indicated that Al and SiC were dominant components as well as others such as Al₄C₃, CuAl₂, and CuMgAl₂. A maximum bending strength of 1400 MPa was obtained for two-layered FGMs which contained 40% SiC (mass fraction) on top layer. A decrease in microhardness and changes in porosity were discussed in relation to the SiC content and the intermetallics formation. The results show that the increase in microhardness values and intermetallic formation play a major role on the improvement of mechanical properties of the composites.

Key words: Al2024/SiC composites; functionally graded materials; intermetallics; microhardness; powder metallurgy