Laser composite surfacing of a magnesium alloy with chromium carbide

Abstract

The present study concerns improving the wear resistance of a Mg alloy (MEZ) by melting the surface with a high power laser and simultaneously injecting hard particles, of Cr₂C₃ +(25mm -40mm) into the surface. The laser processing was carried out using a continuous wave CO₂ laser, Model: Rofin Sinar, RS 10000, with a beam diameter of 4 mm and a focal point 30 mm above the surface. Following laser processing, a detailed investigation of the microstructures, compositions and phases were undertaken and mechanical (wear resistance) and electrochemical (pitting corrosion resistance) properties of the surface layer were evaluated in details. The microstructure of the surface layer consists of uniformly dispersed Cr₂C₃ precipitates in grain-refined matrix. The micro-hardness and wear resistance of the surface layer were significantly improved as compared to the base metal.