Low-temperature plasticity anomaly in the bulk metallic glass Zr _64.13Cu_15.75Ni_10.12 Al₁₀

The plastic deformation and compression fracture of cylindrical samples of the bulk metallic glass Zr64.13 Cu15.75 Ni10.12 Al10 have been studied in the temperature range 300-4.2 K. The deformation curve at 300 K is serrated due to the propagation of narrow shear bands. Catastrophic, uncontrollable fracture of samples, occurring as a result of the propagation of a macroscopic shear band with speed (of the order of 103 ms) comparable to the sound speed, is observed at deformation ∼3-4%. When the temperature is lowered from 300 to 170 and 77 K the deformation changes from serrated to smooth. An interesting low-temperature anomaly of the deformation process is found: "slow" (with speed of the order of 10-6 ms) propagation of a single macroscopic shear band is observed at 170 and 77 K. When the samples are cooled to 4.2 K their macroscopic plasticity vanishes, and they undergo fracture, just as at 300 K, as a result of the propagation of a catastrophic shear band with near-sound speed.