Effect of Rare Earth Oxide on the Microstructure and Wear Properties of In Situ–Synthesized Ceramics-Reinforced Fe-Based Laser Cladding Coatings

Abstract

(Ti,Mo)B2-(Ti,Mo)C-(Fe,Cr)7C3 particle-reinforced laser cladding coatings with different contents of Y2O3 were prepared on a hot forging die steel substrate. The microstructure and wear behaviors were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), block-on-ring room temperature wear testing, and ball-on-disc high-temperature wear testing. The results showed that rectangular-like (Ti,Mo)B2, flower-like (Ti,Mo)C, and granular-like (Ti,Mo)C particles were formed in situ during laser cladding processing. Crack-free coatings with a relatively smooth appearance were obtained with the addition of less than 2 wt% Y2O3. The microhardness of the coatings was improved by adding Y2O3. Among all cladding coatings, the coating with 2 wt% Y2O3 had the highest wear resistance and possessed excellent resistance to ploughing wear and plastic deformation. The dominant wear mechanism of the coatings was adhesive wear. The high-temperature wear resistance of the coating with 2 wt% Y2O3 was about 1.86 and 26.5 times of that of the coating without Y2O3 and substrate, respectively.