Mechanical properties and microstructure of SiC-reinforced Mg-(2,4)A1-1Si nanocomposites fabricated by ultrasonic cavitation based solidification processing

Nano-sized SiC enhanced magnesium matrix nanocomposites, Mg-2A1-1SiC with 2% SiC and Mg-4A1-1Si with 2% SiC, were successfully fabricated by ultrasonic cavitation based dispersion of SiC nanoparticles in Mg-(2,4)A1-1Si magnesium alloy melts. As compared to the magnesium alloy matrixes, the mechanical properties including tensile strength and yield strength of the Mg-2A1-1Si/2% SiC and Mg-4A1-1Si/2% SiC nanocomposites were improved significantly, while the ductility of magnesium alloy matrix castings was retained. While there were some SiC micro-clusters in the microstructure of nanocomposites, the SiC nanoparticles were dispersed well outside the areas of micro-clusters. Most micro-clusters were located along the grain boundaries while most separate SiC nanoparticles were embedded inside the grains. TEM study of the interface between SiC nanoparticles and Mg-(2,4)A1-1Si metal matrixes suggested that SiC bonds well with the metal matrixes without forming an intermediate phase. (C) 2007 Elsevier B.V. All rights reserved.