Elastic moduli of a ZrCuAlNi bulk metallic glass from room temperature to complete crystallisation by in situ pulse-echo ultrasonic echography

Abstract

An in situ ultrasonic echography technique is used to follow the changes in the elastic moduli (Young's modulus and shear modulus) from room temperature to complete crystallisation temperature (~900 K) of a ZrCuAlNi bulk metallic glass. Elastic moduli changes allow to probe the structural transformations of the alloy below and above the glass transition as well as the crystallisation stages. Of peculiar interest is the unusual decrease in Poisson's ratio.

Microscopic description of flow defects and relaxation in metallic glasses

“…However, comparison of data before and after structural relaxation for the same constraining time shows that n , and therefore the corresponding F n , remain the same within 1% following structural relaxation. For the degree of relaxation used, only minor changes in the elastic constants, and therefore on the activation barriers, are expected [26,27]. In Fig.…”

Temperature dependence of mechanical properties and pressure sensitivity in metallic glasses below glass transition

“…G, ZrCuAlNi, from [27] E, ZrCuAlNi, from [23] E, PdNiP, from [24] G, PdNiP, from [24] 111 Figure 7. Normalised indentation stress vs. normalised indentation strain curves for different friction angles α by using the DP yield criterion, for PdNiP (adapted from [33]).…”

“…Figure 2 shows the variations of Young's modulus E and shear modulus G with temperature. Data are taken from our earlier work [23,27] for the ZrCuAlNi or from literature [24] for PdNiP. Linear regression results are indicated in Figure 2 and the slopes are listed in Table 2.…”

Elastic properties and surface damage resistance of nitrogen-rich (Ca,Sr)–Si–O–N glasses

“…Silicate glasses have typically ν values around 0.2-0.25, while oxynitride silicate glasses exhibit higher values, up to 0.36 [24,25]. Metallic glasses generally exhibit Poisson's ratio above 0.3 [26].…”