Recent developments on ultrasonic cavitation based solidification processlng of bulk magnesium nanocomposites

This paper presents the results from our recent development in cast bulk Mg nanocomposites. SiC nanoparticles reinforced magnesium and magnesium alloys including pure magnesium, and Mg-(2, 4)Al-1Si and Mg-4Zn were successfully fabricated by ultrasonic cavitation based dispersion of SiC nanoparticles in magnesium melt. As compared to un-reinforced magnesium alloy matrix, the mechanical properties including tensile strength and yield strength were improved significantly while the ductility was retained or even improved. In the microstructure, the grain size was refined considerably by SiC nanoparticles. While some micro SiC clusters still exist in the magnesium matrix, ultrasonic cavitation based processing is very effective in dispersing SiC nanoparticles. A SEM study showed that SiC nanoparticles were dispersed quite well in the areas outside micro SiC clusters. A TEM study on the interface between SiC nanoparticles and magnesium alloy matrix indicates that SiC nanoparticles bonded well with Mg matrices without forming an intermediate phase.