Effect of Ta2O5 doping content on the organization and properties of AlCoCrFeNi high-entropy alloy coatings cladding by metal 3D printing

Abstract

High-entropy alloy (HEA) coatings can impart high strength, hardness, and corrosion resistance, enhancing the service life of the alloy. This opens up a new path for HEA in practical applications. This research focuses on HEA composite coatings made up of AlCrCoFeNi/x Ta₂O₅ (x = 2, 6, 10, 20 (wt%)) fabricated through the metal 3D printing technique for cladding. A comprehensive investigation was conducted on the morphology, microstructure, electrochemical corrosion, hardness, and dry wear properties of coatings doped with varying contents of Ta₂O₅ particles. This was achieved through including optical microscopy, laser confocal microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The results demonstrated that the prepared coatings exhibited a relatively flat surface without any discernible defects, such as cracks or porosity. The surface of the coating consists of three distinct regions: flat zones, splash particle zones, and overlapping joint zones. The overall morphology is characterized by a rough texture. The surface quality of the coating is optimized when the Ta₂O₅ content is 10%. The coating predominantly comprises face-centered cubic and body-centered cubic (BCC) phases. With an increase in the doping content of Ta₂O₅ particles, the BCC phase and the coating’s hardness also increase. Furthermore, the passivation film on the surface of the coating is predominantly composed of Al, Cr, Fe, Co, Ni, and Ta oxides, exhibiting exceptional stability. The doped of 10 wt% Ta₂O₅ to the coating resulted in excellent corrosion and wear resistance. The highest E_corr value was − 0.65 V, the lowest I_corr value was 7.63 × 10^–6 A/cm², and the largest R_p value was 4693 Ω/cm². Additionally, the coating exhibited the highest surface hardness of the coating exhibited a hardness of 585.58 HV, a wear rate of 6.519 × 10^–2 mm³ N⁻¹ mm⁻¹, and a minimal wear volume of 19.01 mm³. These characteristics are illustrative of the coating’s performance.

Graphical abstract