Tensile Plastic Deformation Behavior of Zr₇₀Ni₁₆Cu₆Al₈ Bulk Metallic Glass at Cryogenic Temperature

Abstract

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 2.3 mm in length and 0.8 mm in diameter at cryogenic temperature (133 K) under different strain rate conditions (10 ¹4 and 10 ¹1 s ¹1). As the results, the tensile plastic deformation occurs under both strain rate conditions. Especially, in low strain rate condition (10 ¹4 s ¹1), the amount of plastic deformation is clearly larger than that under the high strain rate condition (10 ¹1 s ¹1). 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.

Effect of strain rate on yielding strength of a Zr-based bulk metallic glass

“…By performing quasi-static and dynamic tension, Mukai et al [10] argued that the fracture strength (also yielding strength) of a Pd 40 Ni 40 P 20 BMG was essentially independent on strain rate. Similar results had also been found by other researchers at strain rate from 10 −5 s −1 to 10 −1 s −1 in Zr-based BMGs [11,12]. Based on the nanoindentation method, Bhattacharyya et al [13] presented a negative strain rate sensitivity in a Zr-based BMG.…”

Amorphous physics and materials: Secondary relaxation and dynamic heterogeneity in metallic glasses: A brief review

“…(ii) As many previous studies [45,[107][108][109][110] demonstrated that metallic glasses show an excellent plasticity behavior at a cryogenic temperature, it is not known yet whether such temperature dependence of plasticity could be correlated with the secondary relaxation of metallic glasses, particularly the fast  relaxation.…”

Tensile properties of Zr70Ni16Cu6Al8 BMG at room and cryogenic temperatures

“…Lowered temperature is generally predicted to increase strength. Several experimental studies have looked at different BMG alloys in cryogenic conditions, reporting increases in yield strength [11][12][13] and plasticity [11,12,14]. Some report the concentration of deformation into one major shear band rather than several minor ones at low temperatures and strain rates [10,15].…”

“…The plasticity for this alloy was later improved to 2.8 % by increasing the sample cooling rate during casting, entrapping higher free volume to facilitate STZ coordination, as well as by testing at 1.5 x 10 -1 s -1 [22]. This improvement was linked to an increased ability to form multiple shear bands at high strain rates [14,22]. Low temperature and strain rate, i.e.…”