Properties of in-situ formed TiC-VC particle reinforced Fe-based alloy composite coatings produced by laser cladding on 42CrMo roller

By using synchronous powder feeding system, Fe-based cladding layers reinforced with in-situ TiVC2 particles were synthesized on 42CrMo roller by laser cladding the mixture powders of ferrotitanium, ferrovanadium and graphite. The cladding layers have good forming and metallurgical bonding with the substrate, without porosity and cracks. The microstructure and properties of the cladding layers were investigated by means of X-ray diffractometry (XRD), electron probe micro-analyzer (EPMA), microhardness tester and electrochemical workstation. The results show that the carbides in cladding layers are TiVC2 with a size of 0.5~ 2 m and these polygonal carbides distribute evenly in cladding layers. These carbides have two different nucleation mechanisms: the heterogeneous nucleation on alumina and the carbide spontaneous nucleation. With the increasing of Ti-VC in alloy powders, the hardness of cladding layers does not increase linearly, and the corrosion resistance of cladding layers decreases gradually.