Development of SiCp/AZ91 magnesium matrix nanocomposites using ultrasonic vibration

Magnesium matrix nanocomposites reinforced by SiC nanoparticles were fabricated by ultrasonic vibration with SiC nanoparticle size of 60 nm and volume fractions of 0.5%, 1% and 2%, respectively. With increasing the volume fraction of the SiC nanoparticles, grain size of matrix in the SiCp/AZ91 nanocomposites was gradually decreased and morphology of the phase Mg17Al12 was refined compared with as-cast AZ91 alloy. Most of the SiC nanoparticles exhibited a homogeneous distribution in the 0.5 and 1 vol.% SiCp/AZ91 nanocomposites. The ultimate tensile strength, yield strength and elongation to fracture of the 0.5 and 1 vol.% SiCp/AZ91 nanocomposites were simultaneously improved. However, agglomerates of SiC nanoparticles along the grain boundaries were evidently increased when the volume fraction of nanoparticles was increased to 2, which caused the decrease of ultimate tensile strength and elongation to fracture.