Effect of enthalpy relaxation rejuvenation on microstructure and corrosion resistance of a Zr-based bulk metallic glass

Abstract

Enthalpy relaxation rejuvenation is a recently developed promising method for modulating mechanical properties of metallic glasses (MGs), but its effect on corrosion resistance, which is important for applications of MGs, has never been studied before. This paper studies its effects on microstructure and corrosion of a Zr_52.5Cu_17.9Ni_14.6Al₁₀Ti₅ bulk metallic glasses (BMGs) in 3.5 wt% NaCl solution. The results show that the system energy increases after rejuvenation, but the content of local ordering structure, which results in chemical inhomogeneity, is almost changeless, as compared to the structure-relaxed state. The enthalpy relaxation rejuvenation has minimal effects on passivation and pitting corrosion of structure-relaxed samples, with no apparent adverse effects. Since pitting corrosion of Zr_52.5Cu_17.9Ni_14.6Al₁₀Ti₅ BMGs is dominated by pit initiation and chemical inhomogeneity could initiate pitting corrosion, this minimal effect is attributed to the nearly unchanged chemical inhomogeneity of rejuvenated samples. This finding provides valuable information for industrial applications of Zr-based BMGs.