Microstructure and tribological evolution during laser alloying WC-12%Co and Cr3C2−25%NiCr powders on nodular iron surface

Abstract

The laser surface alloying has emerged as an important tool to form wear resistant layer. In this work, the characteristics of laser alloyed WC-12%Co and Cr3C2-25%NiCr powders over nodular cast iron and their effects on microstructure, microhardness and wear resistance properties has been investigated. Results shows that the laser alloyed layers are crack free with a very fine structure, improved homogeneity and good metallurgical bonding with the substrate. Microhardness of the alloyed layer has been remarkably increased from 220 HV0.3 to 1199 HV0.3 and 905 HV0.3. The results shown that the wear resistance of the laser alloyed layer was improved by 97.77% and 89.77% for WC-12%Co and Cr3C2−25%NiCr, respectively, compared to that of the substrate nodular cast iron. The enhancement in wear resistance was due to the combined results of the solution strengthening effect, grain refining and good bonding between the hard phases and the matrix. Keywords: Laser surface alloying (LSA), Microhardness, XRD, Wear, Whitelight interferometer