In situ synthesis and characterization of Fep/Cu composite coating on SAE 1045 carbon steel by laser cladding

Fe particulate composite coatings have been successfully in situ synthesized with a preplaced mixture of Cu+5 wt.% Al on SAE 1045 carbon steel substrate using a 2 kW CW CO2 laser. Microstructural analysis reveals that Fe-rich spherical particles are embedded in the Cu-matrix. At a low scanning speed of 5 mm s−1, the Fe-rich spherical particles are homogeneously dispersed in the matrix other than near the bonding interface where there are dendrites. Upon increasing the scanning speed (9 or 13 mm s−1), the dendritic microstructures disappear, the distribution of the Fe-rich spherical particles becomes heterogeneous and the Fe-rich belt along the convection currents can be observed in the clad. Area percentage of these Fe-rich particles and electrical resistivity decreased with an increase of the scanning speed. Finally, the in situ formation mechanism of the Fe-rich spherical particles is discussed in detail.