Microstructure and mechanical properties of TiC/Co composite coating by laser cladding on H13 steel surface

TiC/Co composite coating and Co50 alloy coating were prepared by laser cladding of on the AISI H13 hot work tool steel surface.The bonding characteristics,phase constitution, microstructure and micro-hardness distribution of the coatings were analyzed and tested by XRD,SEM and micro-hardness tester.The results indicate that Co50 alloy coating as well as TiC/Co composite coating show good metallurgical bonding with the H13 steel substrate surface.Co50 alloy coating was mainly composed of γ-Co dendrite and eutectic between γ-Co dendrites, while TiC/Co composite coating which contained TiC particles, dendrite and fine eutectic,was consisted of TiC,TiCo₃,Cr₂Ni₃ as well as Cr-Ni-Fe-C,and so on.The average micro-hardness of cross-section of TiC/Co-based composite coating and Co50 alloy coating are 5520 MPa and 4990 MPa,about 2.7 times and 2.4 times higher than that of the H13 steel substrate.