Fabrication of silicon carbide reinforced aluminum matrix nanocomposites and characterization of its mechanical properties using non-destructive technique

The SiC nanoparticulate reinforced Al matrix composites (with 2.5-12.5 vol%) were successfully fabricated by employing high energy ball milling with cold-pressing and sintering technology at 550 °C for 1 h. Microstructures and nanoparticulate distribution were analyzed with scanning electron microscope (SEM), X-ray diffraction (XRD) and transmission electron microscope (TEM). Mechanical property and hardness were studied using pulse echo overlap (PEO) method as a non-destructive technique. Microstructure analysis showed that the nanocomposites contained only α-Al and SiC phases with clean interface of thickness ∼1.5 nm, and preserved nano-grained network structure. The SiC nanoparticulates were distributed uniformly in a metal matrix, and neither voids nor cracks were detected at the interface of Al/SiC. Besides, there was no reaction product has been found at the interface. Accordingly, the mechanical properties of composites reinforced by SiC nanoparticulates were significantly improved, while the Poisson's ratio of nanocomposites was retained. This was mainly due to the stronger interfacial bonding derived from direct mechanical interlocking between the adjacent component surfaces.