The Effect ofY2O3 Content on the Microstructure and Properties of Stellite 6 +Y2O3 Laser Cladding Layers on the Surface of 17-4PH Steel

Abstract:

In this study, wear-resistant and corrosion-resistant cobalt-based Stellite 6 alloys were prepared by varying the Y2O3 content (0, 0.3, 0.6, and 0.9 wt%). The effects of Y2O3 addition on the microstructure, microhardness, wear resistance, and corrosion resistance of the laser-cladded Stellite 6 samples were investigated. The results indicate that the addition of Y2O3changes the grain structure from coarse columnar grains to fine, uniform equiaxed grains. The sample with 0.6 wt%of Y2O3exhibits an average grain size of 160.8 μm, representing a maximum grain refinement of 66.3% compared to the sample without of Y2O3 addition.Furthermore,of Y2O3particles are mainly dispersed in the interdendritic regions of the Stellite 6 alloy samples, forming a particle layer in front of the dendrite grains, which inhibits grain movement and solute atom diffusion.The sample with 0.6 wt% of Y2O3addition shows the highest microhardness, with an average value of 532 HV0.2. Due to the smallest grain size and spacing between of Y2O3 particles, it also demonstrates the best wear and corrosion resistance performance. Compared to the sample without of Y2O3addition, the maximum microhardness increases by 22.6%, the wear rate decreases by up to 72.2%, the corrosion potential increases by up to 25.6%, and the corrosion current density decreases by up to 39.8%.