Mechanical properties and corrosion resistance of a new Zr₅₆Ni₂₀Al₁₅Nb₄Cu₅ bulk metallic glass with a diameter up to 25 mm

The glass-forming ability (GFA), mechanical properties and corrosion resistance of Zr₅₆Ni_25-xAl₁₅Nb₄Cu_x (x = 0-15) bulk metallic glasses (BMGs) were investigated. Substitution of 5 at.% Cu for Ni greatly increases the GFA of the base alloy by lowering the liquidus temperature, while further addition of 10-15 at.% Cu decreases the GFA. A new Zr₅₆Ni₂₀Al₁₅Nb₄Cu₅ BMG with a largest critical diameter up to 25 mm can be obtained by copper mold casting method. The BMG with best GFA possesses good mechanical properties, i.e., high strength of 1915 MPa, large plastic strain of 5.5%, together with Young's modulus of 100 GPa. In addition, the BMG exhibits excellent corrosion resistance in H₂SO₄, HCl, and NaCl solutions, respectively, as indicated by the nobler corrosion potential and pitting potential.