An Experimental Study on the Role of Partial Replacement of Y with Ce in a Novel Quinary AlNiCoYCex High Entropy Metallic Glasses.

For the balanced consumption of pricey rare-earth element yttrium (Y) and improved pitting corrosion resistance of alloys, Y was partially substituted by cerium (Ce) in a novel kind of quinary AlNiCoYCe_x high-entropy metallic glass (HE-MG) via vacuum arc melting and rapid solidification. The microstructure, thermal stability and micro-hardness of Al₃₀Ni₃₀Co₈Y_32-xCe_x (x = 1, 2, 3, 4, 5, and 8 at%) high-entropy metallic glass ribbons (hereafter referred to as HE-MG ribbons) have been systematically investigated. In addition, the electrochemical corrosion properties of these amorphous ribbons with different Ce content in 3.5 wt.% NaCl solution have been determined by potentiodynamic polarization and electrochemical impedance spectroscopy. After 100 h immersion in corrosive media, scanning electron microscope images of the corroded ribbons were also characterized. The results indicated that these ribbon samples could remain in an amorphous state, and the that micro-hardness was more than 495 HV_0.1. With increasing Ce content, the thermal stability started to gradually increase and then decrease. Furthermore, Ce is responsible for an improvement in anticorrosion performance compared with the Ce-free alloys. Ce-containing HE-MG ribbons showed a passive region in the electrochemical reaction, and ribbons with 3 at% Ce exhibited the most corrosion resistance by virtue of the smallest I_corr and I_pass. [ABSTRACT FROM AUTHOR]