Effects of Scanning Speed on Microstructure and Wear Resistance of Cu80Fe20 Immiscible Coatings Prepared by Laser Cladding

The Cu80Fe20 immiscible coating is fabricated by laser cladding technique and the effects of scanning speed on the liquid phase separation characteristics, microhardness and wear resistance of the immiscible coating are investigated. The research results indicate that the delamination phenomenon appears in the Cu80Fe20 immiscible coatings; a large amount of Fe-rich particles consist of body-centered-cubic (bcc) alpha-Fe, face-centered-cubic (fcc) gamma-Fe are dispersed in the upper fcc epsilon-Cu matrix, and a large amount of epsilon-Cu Cu-rich particles are distributed in the lower alpha-Fe matrix. With the increase of the laser scanning speed, the cooling rate of the molten pool increases and the size of Fe-rich particles decreases, while the surface density of Fe-rich particles increases, the spacing of neighbouring Fe-rich particles decreases, and therefore the shadow protection effect of Fe-rich particles on the Cu-rich matrix is enhanced, leading to the improvement in microhardness and wear resistance of the immiscible coating, which are both higher than those of brass.