FABRICATION OF Mg/SiC NANOCOMPOSITE SURFACE LAYER USING FRICTION STIR PROCESSING TECHNIQUE

摘要

Friction stir processing (FSP) was employed to incorporate nano-sized SiC particles into the surface of AZ31 magnesium substrate in order to produce surface nanocomposite layers. Characterization of the microstructure of the processed layers exhibited powders agglomeration which was found to disperse with increasing the tool rotation speed/advancing speed ratio. A uniform distribution of SiC particles with a mean particle size of ～95 nm was achieved after second FSP passes. The matrix grain size was found to decrease by increasing the tool advancing speed and number of FSP passes; however, increasing the advancing speed resulted in introduction of defects which leads to tunnels. The micro hardness value of the composite layer with uniform distribution of nano-size SiC particles was found to be almost twice of that of the AZ31 substrate.