Tensile plastic deformation behavior of Zr ₇₀Ni ₁₆Cu ₆Al ₈ bulk metallic glass at cryogenic temperature

A hypoeutectic ZrNiCuAl bulk metallic glass (BMG) shows a clear tensile plastic deformation under a high strain rate condition at room temperature. In this study, the effect of cryogenic temperature and strain rate on the tensile plastic deformation behavior of the hypoeutectic ZrNiCuAl BMG was investigated. Tensile tests were performed for the hypoeutectic ZrNiCuAl BMG specimen with gauge part dimensions of 2.3mm in length and 0.8mm in diameter at cryogenic temperature (133 K) under different strain rate conditions (10 ^-4 and 10 ^-1 s ^-1). As the results, the tensile plastic deformation occurs under both strain rate conditions. Especially, in low strain rate condition (10 ^-4 s ^-1), the amount of plastic deformation is clearly larger than that under the high strain rate condition (10 ^-1 s ^-1). Furthermore, it was found that there is no positive correlation between the amount of tensile plastic deformation and the number of shear band. In addition, it was inferred that the tensile plastic deformation of the hypoeutectic ZrNiCuAl BMG at cryogenic temperature was induced by specimen sliding along only one major shear band.