Low-temperature plasticity anomaly in the bulk metallic glass Zr64.13Cu15.75Ni10.12Al10

Abstract

The plastic deformation and compression fracture of cylindrical samples of the bulk metallic glass Zr64.13Cu15.75Ni10.12Al10 have been studied in the temperature range 300–4.2K. The deformation curve at 300K 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 103m∕s) comparable to the sound speed, is observed at deformation ∼3–4%. When the temperature is lowered from 300 to 170 and 77K 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 10−6m∕s) propagation of a single macroscopic shear band is observed at 170 and 77K. When the samples are cooled to 4.2K their macroscopic plasticity vanishes, and they undergo fracture, just as at 300K, as a result of the propagation of a catastrophic shear band with near-sound speed.