Synergistic improvement of mechanical performance and corrosion resistance in Zr-based BMGs by Nb addition

Abstract

In this study, Zr₆₁Cu_19-xAl₁₀Ni₁₀Nb_x (x = 0, 1, 3, 5 at.%) bulk metallic glasses (BMGs) were fabricated through vacuum arc melting, with argon shielding to prevent oxidation. To unravel the role of Nb in tailoring alloy properties, correlations between doping content and key characteristics including thermal hysteresis, compressive plasticity, and electrochemistry behavior were established. The XRD analyses showed that all the alloys showed typical amorphous structure without crystallization or phase separation. Thermodynamic analyses show that the addition of Nb can enhance the thermal stability of the alloy, but when its content exceeds 3 at.%, the glass forming ability (GFA) decreases. Mechanical tests show that the alloy has the best overall performance at x = 3 at.%, with the yield strength and plasticity reaching 1673.0 MPa and 6.9%, respectively, which are 101.2 MPa and 4.6% higher than that of the base alloy (x = 0); microscopic characterization reveals that an appropriate amount of Nb promotes the branching and expansion of shear bands through the atomic size effect, thus enhancing the plasticity. Electrochemical tests showed that the alloy at x = 3 at.% had the lowest self-corrosion current density (2.24 × 10^-8 A/cm²) and the highest charge transfer resistance (R_ct) in 3.5% NaCl solution. This research offers a theoretical foundation for developing and utilizing BMGs with exceptional durability and resistance to corrosion.