Influence of the Structural State on the Corrosion Resistance of Zr-Based Bulk Amorphous Alloys

To elucidate the influence mechanism of structural rejuvenation on the corrosion resistance of bulk amorphous alloys, Zr_52.5Cu_17.9Al₁₀Ni_14.6Ti₅ bulk amorphous alloy is prepared by arc melting combined with copper mold suction casting. The effect of the initial structural state on the structural rejuvenation and corresponding corrosion resistance of the alloy is systematically investigated. The results indicate that sub-T_g annealing significantly enhances the corrosion resistance by promoting structural relaxation and homogenization. For instance, after annealing at 0.9T_g for 1 h, the corrosion current density is decreased by approximately 57% compared to the as-cast state. In contrast, structural rejuvenation, as the reverse process of annealing, deteriorates the corrosion resistance by exacerbating structural heterogeneity. Specifically, after thermal cycling of the sample annealed at 0.7T_g, the corrosion current density is increased by 73.22%, and the pitting potential shifted negatively by approximately 25 mV. In addition, the effect of structural rejuvenation on the deterioration of corrosion resistance strongly depends on the initial structure of the bulk amorphous alloys. This work provides an important scientific basis for understanding of the correlation between structural state and corrosion resistance of bulk amorphous alloys.