Effect of SiC content and interlayer difference on microstructural characterization and mechanical properties of functionally graded 6061Al/SiCp composites

Abstract

Metal matrix composite reinforced gradiently by ceramic phase is a new type of high-tech material with broad application prospects, and the study of the effect of SiC content and interlayer difference on functionally graded materials (FGMs) is vital for the guiding significance of the practical application. Functionally graded 6061Al/SiCp composites (6061Al/SiCp FGMs) were prepared by hot pressing sintering herein, and mechanical properties were evaluated by tensile tests conducted under different temperatures. 6061Al/SiCp FGMs were observed under optical microscopy to identify the particle distribution and transition status between layers, and fracture surfaces were observed to verify the detailed fracture mechanisms. Results show that 6061Al/SiCp FGMs achieving high relative densities of more than 0.99 satisfy requirements of microstructure. When the interlayer difference is consistent, the tensile strength of FGMs increases as the SiC content increases in each layer constituting FGMs, and FGMs have the highest tensile strength at room temperature. The elongation of FGMs decreases as the SiC content increases in each layer constituting FGMs, and FGMs have the highest elongation at 100 °C. When the intermediate layer is consistent, the tensile strength of FGMs with a lower interlayer difference is better, which can be attributed to the interaction of elongation and dislocation.