FORMATION OF HYBRID CLAD LAYERS BY LASER PROCESSING

Laser cladding is an effective material processing that produces a surface layer having good wear and corrosion properties with minimized dilution. In the present work, Co based hardfacing alloy claddings by the blown powder process and Ni-Cr-Al-Y alloy claddings by the preplaced powder process were performed. Formation behavior of the laser clad layers and their properties were investigated. Low dilution in the laser cladding process using powder materials was attributed to low melting efficiency for substrate melt due to indirect heat transfer via melting clad layer. For wear properties, carbide reinforcing improved wear resistance of the Co based hardfacing alloy claddings. Superior oxidation resistance was obtained in the Ni-Cr-Al-Y claddings. Chromium carbide reinforcing improved wear resistance of the Ni-Cr-Al-Y alloy cladding with a little sacrifice of oxidation resistance.