Effect of substrate types on the microstructure and properties of Cu65Fe35 composite coatings by laser induction hybrid cladding

The Cu65Fe35 (wt.%) composite coatings with a liquid miscibility gap were produced on the different substrates by laser induction hybrid cladding (LIHC) to investigate the effect of substrate types on the microstructure and properties. The microstructure of composite coating on Fe-substrate is characterized by Cu-rich particles embedded in Fe-rich layer and Fe-rich particles dispersed in Cu-rich layer, resulting in Cu-p/Fe-Fe-p/Cu "duplex-layer structure". When Cu-substrate is adopted, the interlayer is Fe-rich layer where Cu-rich particles are distributed, and is enveloped by the upper and lower Cu-rich layers where Fe-rich particles are embedded dispersedly, resulting in Fe-p/Cu-Cu-p/Fe-Fe-p/Cu "sandwich-layer structure". Moreover, the composite coating on Fe-substrate presents the characteristic of "duplex-microhardness", which is composed of Fe-rich layer with higher microhardness and Cu-rich layer with lower microhardness. The composite coating on Cu-substrate presents the characteristic of "sandwich-microhardness", which is composed of Fe-rich interlayer with higher microhardness, lower and upper Cu-rich layer with lower microhardness. With increasing distance from the interface of coating/substrate, the microhardness of heat-affected-zone (HAZ) in Fe-substrate decreases, while that of HAZ in Cu-substrate decreases first and then increases. The electrochemical resistance of composite coating on Fe-substrate is higher than that of composite coating on Cu-substrate, Brass, and middle carbon steel (MCS). (C) 2017 Elsevier B.V. All rights reserved.