Effect of Ni Content on the Microstructure and Properties of a Laser Clad Fe-based Ultrafine Grained (UFG) Layer
M-C. Sui, Y. Zhang, S-T. Jiang, W. Zhao and H. Zhang
The effect of Ni content on the microstructure and properties of an ultrafine grained (UFG) Fe-based layer clad onto a Q235 steel with a fibre laser was examined. The results revealed that within the range of 0 to 6 wt.% Ni, each Fe-based UFG laser clad layer consisted of α-Fe, γ and in situ synthesized VC. As the Ni content increased so the grain size of the Fe-based UFG laser clad layer matrix and the amount of retained austenite also increased. The microhardness of the Fe-based UFG laser clad layers initially decreased and then increased with the addition of Ni. The corrosion resistance of the Fe-based UFG laser clad layers exhibited an increasing trend followed by a decreasing trend. Notably, when the Ni content ranged from 4.5 to 5.2%, the Fe-based UFG laser clad layer demonstrated excellent comprehensive performance, including outstanding corrosion resistance and microhardness.
Keywords: Fibre laser, Ni, Q235 steel, Fe-based powder, VC, ultrafine grained (UFG), laser cladding, microstructure, microhardness, corrosion resistance