Preparation and electrochemical corrosion performances of Zr-Ti-Ni-Cu-Be high-entropy bulk metallic glasses

Abstract

The high entropy bulk metallic glasses (HE-BMGs) are the mathematical intersection of sets of bulk metallic glasses (BMGs) and high entropy alloys (HEAs). Owing to their unique structural and compositional features, HE-BMGs exhibit peculiar physical, chemical, and mechanical properties. Herein, non-equiatomic alloys ZrxTiNiCuBe (x = 1.5, 2, 2.5, 3, and 3.5 at. %) HE-BMGs were designed according to the atomic size difference (δ), mixing enthalpy (ΔHmix), mixing entropy (ΔSmix), valence electron concentration (VEC) and electronegativity difference (Δχ) parameters. The electrochemical corrosion behaviors in 1 mol/L H2SO4 and 3.5% NaCl solutions were also studied in this paper. The results show that fully glassy rods with diameters of 6 mm were obtained. The designed HE-BMGs show large glass forming ability, a narrow supercooled liquid region and a wide crystallization region compare with the traditional BMGs. In 1 mol/L H2SO4, the designed HE-BMGs show very small corrosion current densities and a typical passivation behavior, and their corrosion resistance is much better than that of 304L stainless steel. In 3.5% NaCl, the prepared HE-BMGs also have much smaller corrosion current densities than 304L stainless steel. As potential increases, the pitting corrosion resistance is not as good as 304L stainless, however, the HE-BMGs all show superior pitting corrosion re-passivation abilities.