Critical Poisson’s ratio for plasticity in Fe–Mo–C–B–Ln bulk amorphous steel

Fracture in compression has been investigated in ${\mathrm{Fe}}_{65}{\mathrm{Mo}}_{14}{\mathrm{C}}_{15}{\mathrm{B}}_6$ bulk amorphous steel doped with lanthanides to provide systematic variations of the elastic moduli. An onset of plasticity is observed as Poisson’s ratio approaches 0.32 from below. Combining with previous analysis reported by Lewandowski et al. [Philos. Mag. Lett. 85, 77 (2005)] using single-composition results from different sources, the findings are in support of universal critical Poisson’s ratio for plasticity in metallic glasses. The compositional dependences of elastic moduli are found to be anomalous considering the elastic moduli of the alloying elements. The role of interatomic interactions in designing ductile metallic glasses is suggested.