A series of quinary (Al 1/4 Ni 1/4 Zr 1/4 Co 1/4) 100- x Y x (x = 16–28 at.%) high entropy metallic glass ribbons were successfully fabricated through the high-speed single roller melt-spinning method. The effects of rare-earth element yttrium content on the microstructure and performances of alloy ribbons were systematically investigated by X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), heat treatment, transmission electronic microscopy (TEM), atomic force microscopy (AFM) and electrochemical experiments. The microhardness of metallic ribbons was measured by Vickers hardness tester. Results show that the microstructure of the as-quenched alloy ribbons maintain the glassy state and the average microhardness value of each specimen can reach 488 HV 0.1 or above. The surface morphologies of the as-spun ribbon samples exhibit the smooth surface with small roughness value of R a = 0.115–0.150 nm. In the meantime, with the increase of Y content, the glass transition temperature can be detected in the DSC traces when Y content is over 22 at.%, and the crystallization onset temperature shifts to the lower temperature region, suggesting that the thermal stability of amorphous state in Al–Ni–Zr–Co–Y alloy ribbons has been weakened. The (Al 1/4 Ni 1/4 Zr 1/4 Co 1/4) 84 Y 16 alloy ribbons own the highest crystallization onset temperature (∼742 K). Adding appropriate yttrium element can enlarge the super-cooled liquid region and improve the glass-forming ability. In 3.5 wt% NaCl solution, the prepared alloy ribbons can maintain smaller corrosion current densities (∼10−8 A cm−2) than traditional Al-based amorphous alloys, 6061 Al alloy and other common structural steels. The X-ray photoelectron spectrometer results indicate that the passive film of equiatomic alloy ribbons is rich in oxides of Al, Zr, Co, and Y elements, which has excellent resistance to chloride ion attack. On the basis of all experimental results, (Al 1/4 Ni 1/4 Zr 1/4 Co 1/4) 84 Y 16 alloy ribbons can optimally combine outstanding corrosion resistance, superior thermal stability, and acceptable microhardness. The above research results lay a solid foundation for the composition development of high-performance high entropy metallic glasses. Rare-earth element can be conducive to the formation of amorphous structure in high entropy alloys. Aluminum-based amorphous alloys, which had the features of high-strength, low-density, good flexibility properties, excellent corrosion resistance and so forth, are recognized as critical metallic materials from the viewpoint of marine corrosion and protection. Combining with the design concepts of high entropy alloys and amorphous alloys, this research investigates the influence of yttrium content on the microstructure and properties of a novel quinary Al-containing high entropy metallic glass ribbons prepared by melt spinning method. Higher Vickers hardness, superior thermal stability and excellent anti-corrosion performance can be attained simultaneously, on condition that the content of rare-earth element Y is kept within an appropriate range. [Display omitted] • A series of quinary Al-containing high entropy metallic glasses developed through the high-speed melt-spinning technique. • By increasing Y content, the investigated HE-MG ribbons maintain fully amorphous nature and the obvious glass transition can be observed. • The thermal stability of amorphous ribbons decreases with the addition of Y and the Vickers hardness can reach 488 HV 0.1 or above. • The HE-MG ribbons with 16 at.% Y exhibit the outstanding corrosion resistance, superior thermal stability and acceptable microhardness. [ABSTRACT FROM AUTHOR]