Microstructure and Properties of Fe-(TiC, Mo) Composite Coatings Laser Clad onto Q235 Steel
X. Li, L-Y. Gao, W. Zhao and H. Zhang
The Fe-(TiC, Mo) composite coating was laser clad onto the surface of Q235 steel, and the study delved into the impact of (TiC, Mo) content (x) on the coating’s microstructure, microhardness, wear resistance and corrosion resistance. The results revealed that as x varied from 0 to 10, 20 and 30 wt.%, the phase composition shifted from a-Fe to a-Fe+g-Fe+TiC. This transition was accompanied by a constant variation in the proportion of different phases, with a continuous increase in in situ TiC particle content. The microhardness, wear resistance, and corrosion resistance of the coating displayed an initial increase followed by a subsequent decrease with the increase in x, reaching their optimal values at 20 wt.%. This enhancement in microhardness and wear resistance, up by 4.34 and 8.27 times, respectively, can be attributed to fine crystal strengthening, dispersion strengthening, and solid solution strengthening. Furthermore, the incorporation of (TiC, Mo) in the coating facilitated the formation of a dense and uniform passivation film, while grain refinement mitigated the galvanic corrosion effect. As a result, the coating exhibited remarkable corrosion resistance.
Keywords: Fibre laser, Fe, TiC, Mo, Q235 steel, metal matrix composite (MMC), laser cladding, microstructure, wear resistance, electrochemical corrosion