Bending ductility of stress-relieved Fe–Zr–B metallic glasses with pronounced β-relaxation.

Fe-based metallic glasses are known to have excellent soft magnetic properties, but restricted to the disastrous annealing embrittlement. A novel class of Fe 84- x B 14+ x Zr 2 (x = 0, 3, 6) metallic glasses with extraordinary annealing bending ductility and excellent soft magnetic properties were developed. The metallic glasses exhibit a high B S of 1.54–1.64 T and a low H C of 4.1–5.8 A/m. It is noteworthy that the Fe 84 B 14 Zr 2 metallic glass exhibits the highest ductile to brittle transition temperature among all Fe-based metallic glasses reported to date and the ductile to brittle transition temperature decreases with the decrease of Fe content. Moreover, the well-distributed shear bands can still be formed during bending for Fe 84 B 14 Zr 2 metallic glass after 680 K annealing. Pronounced β-relaxation peak has been observed for Fe 84 B 14 Zr 2 metallic glass in its relaxation spectra. We demonstrate that the bending deformation ability is closely correlated to the β-relaxation. The underlying mechanism for the extraordinary bending deformation ability of Fe 84 B 14 Zr 2 metallic glass after annealing can be attributed to the heterogeneous structure with plenty of loosely packed zones as revealed by the pronounced β-relaxation and high resolution transmission electron microscopy. • Fe 84 B 14 Zr 2 MG with good soft magnetic properties exhibits extraordinarily high DBT temperature. • Fe 84 B 14 Zr 2 MG shows pronounced β-relaxation, relating to plenty of loosely packed zones. • The β-relaxation is regarded as an indication for the bending ability of metallic glasses after annealing. [ABSTRACT FROM AUTHOR]