Effect of Y2O3 on microstructure and properties of CoCrFeNiTiNb high entropy alloy coating on Ti–6Al–4V surface by laser cladding

• Published in: Journal of rare earths Vol. 42; no. 3; pp. 586 - 599
• Main Authors: Li, Zhen, Zhao, Wei, Yu, Kedong, Guo, Ning, Xiao, Guangchun, Wang, Zhiming, Zhang, Hui
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.2024
• Subjects: Electrochemical corrosion; High entropy alloy coatings; High temperature properties; Laser cladding; Rare earths; Wear properties; High temperature properties; Wear properties; High entropy alloy coatings; Electrochemical corrosion; Laser cladding; Rare earths
• ISSN: 1002-0721; 2509-4963
• DOI: 10.1016/j.jre.2023.02.015

The effects of Y2O3 on the microstructure, microhardness, wear resistance, high-temperature oxidation resistance, hot corrosion resistance, and electrochemical corrosion behaviour of CoCrFeNiTiNb high entropy alloy coatings formed on Ti–6Al–4V alloy surfaces were studied. The results show that the addition of Y2O3 changes the proportion of the phase but does not change its type. The average grain size is only 1/4.7 of that of the high entropy alloy (HEA) coating, and the fine-grained strengthening leads to increases in the microhardness and wear resistance of 21.8% and 26.9%, respectively. The addition of Y2O3 enhances the denseness and bonding properties of the oxide and corrosion product layers, reducing the oxidation and hot corrosion rates by 60.3% and 40.3%, respectively. The addition of Y2O3 doubles the corrosion resistance which is attributed to the refinement of the grains, the increased proportion of HCP and TiN, and the weakening of galvanic coupling corrosion. The addition of Y2O3 refines the grains of CoCrFeNiTiNb high entropy alloy, and improves the wear resistance, high temperature oxidation resistance, hot corrosion resistance and corrosion resistance of the coating. [Display omitted] •The addition of Y2O3 changes the phase proportion and refines the grain size.•The fine-grained strengthening improves the mechanical properties of the coatings.•The mechanism of Y2O3 improving oxidation and hot corrosion resistance was explored.•The corrosion resistance of HEA coating is doubled when Y2O3 is added.