Investigation of the Microstructure and High-Temperature Performance of Laser-Clad Ni50(AlNbTiV)50-xY2O3 Complex-Concentrated Alloy Composite Coatings

This study prepares Ni₅₀(AlNbTiV)₅₀-xY₂O₃ complex concentrated alloy composite coatings and analyzes their microstructure, phase composition, and high-temperature performance. The results indicate that each coating is composed of FCC phases, including γ-FeNi, Ni₃Al, and Ni₃(Al, Ti), as well as BCC phases such as Ni₃Nb and Ni₃Ti. With increasing Y₂O₃ content, the lamellar structure in the inter-dendritic regions of the coatings first decreases and then increases. The wear mechanism of the coating without Y₂O₃ addition under high-temperature conditions involves the combined effects of abrasive wear and adhesive wear. The coating with a 0.6 wt.% addition exhibits the smallest cracks and the lowest oxidation rate in high-temperature oxidation and thermal shock tests, with the oxidation weight gain reduced by 26.2% compared to the coating without Y₂O₃ addition. The abrasive and adhesive wear of this coating is mitigated, and the average friction coefficient and mass loss are decreased. When the mass fraction of Y₂O₃ is 0.4 wt.%, the coating structure shows a significant refinement effect and exhibits the best performance in tensile strength and high-temperature friction and wear tests.