Nano-sized SiC particle reinforced AZ61 magnesium matrix composites SiCp/AZ61 was prepared by a self-developed high-energy ultrasonic device

and microstructure and damping behavior of the prepared composites were investigated by OM （optical microscope） and SEM （scanning electron microscope）. The results reveal that SiCp particles can be uniformly and dispersedly distributed in the magnesium alloy melt by high energy ultrasonic. The damping behavior of the composites is greatly superior to that of AZ61 matrix alloy at room temperature

which is attributed to G-L dislocation-pinning theory. Interface slipping at high temperature can be easily conducted due to SiCp increasing the quantities of grain-boundaries of matrix alloy

resulting in the significant improvement of damping behavior of the composites.