Investigation of in-situ formed Ti(C, N)particle reinforced Febased alloy composite coatings on adamite by laser cladding

A new method is realized to produce Fe-based alloy composite coating reinforced by Ti(C, N) particle on the substrate named Adamite steel through laser cladding technology.The microstructure of laser cladding layer is analyzed by means of optical microscopy (OM), X-ray diffractionmetry (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS)and electron probe microscopy analyzer (EPMA).The microhardness of laser cladding layer is measured by microhardness meter.The results show that Ti(C, N)particle is introduced by an in-situ metallurgical reaction of TiN particle and graphite powder during laser cladding process.At the beginning of laser cladding process, TiN particle is decomposed by high laser heat energy, TiN→Ti+N.At the same time, the new particle named Ti(C_0.3N_0.7)and Ti(C_0.2N_0.8) comes into being by the following chemical combination reactions,Ti+C→TiC,Ti+N→TiN, xTiC +(1-x)TiN→Ti (C_xN_1-x).The fine Ti(C, N) particle is dispersed evenly in the matrix.Size of the Ti(C, N) particle is within 0.1-5 mm.The shape of some Ti(C, N)particle is similar to rotundity, and the other is irregular shape.The microhardness of laser cladding layer is distributed within HV_0.2 800-900.