A plastic Zr–Cu–Ag–Al bulk metallic glass

An intrinsically plastic Zr53.8Cu31.6Ag7.0Al7.6 bulk metallic glass with large bending and compressive plastic strains was fabricated. Through transmission electron microscopy, three-dimensional atom probe and anomalous small-angle X-ray scattering techniques, the possibility of plasticity induced by microstructural and chemical inhomogeneity was ruled out in the as-cast alloy. The plasticity can change dramatically in a narrow composition range, even though all the other properties vary slightly or even do not change. In comparison with Zr46Cu37.6Ag8.4Al8, the increase in Zr content in Zr53.8Cu31.6Ag7.0Al7.6 results in an increased portion of the Zr–Zr atomic pair in the nearest shell of a pair distribution function. A steep peak profile on the right side of the pair distribution function in Zr53.8Cu31.6Ag7.0Al7.6 suggests that more atoms are involved upon yielding, and the opportunity of forming more shear bands increases. This finding may provide useful guidelines for the development of plastic metallic glasses from a structural aspect.