Microstructure of a laser surface melted SiC particle reinforced aluminum metal matrix composite

A SiC particle reinforced aluminum matrix composite (SiCp/Al composite) is melted by a high power continuous wave CO₂ laser. Microstructure of the laser melted SiCp/Al MMC is studied as functions of laser processing parameters. The silicon carbide particles are completely dissolved during laser surface melting and aluminum silicon carbide Al₄SiC₄, aluminum carbide Al₄C₃, and primary silicon particles are produced in the laser melted surface. The size and volume fraction of the newly formed phases depend on the processing conditions. The relative volume fraction of Al₄SiC₄ to Al₄C₃ is strongly dependent on the laser linear energy density, a higher linear energy density leading to more Al₄SiC₄ formation. Result of anodic polarization corrosion test indicates that the corrosion resistance of the SiCp/Al MMC is not improved after laser surface melting.