Effect of temperature on the mechanical behaviour of a Ni-free zirconium-based bulk metallic glass

It is well known that nickel-free zirconium-based bulk metallic glasses are of interest for their possible good biocompatibility properties. In this framework, a Zr-Nb-Cu-Al-Fe bulk metallic glass was elaborated under the form of 2 mm diameter rods. The amorphous structure was confirmed by XRD and DSC and the associated reduced index were measured The mechanical properties of the glass were investigated at both room and high temperature. At room temperature, the glass exhibits some macroscopic plasticity The rheology at high temperature was studied by both strain rate jump tests and tests at constant strain rate. From these tests, It was difficult to identify an experimental window in which the amorphous structure could be maintained and in which viscoplastic forming could be carried out under low flow stresses. In the super-cooled liquid region, this behaviour is discussed in relation with the resistance to crystallization of the investigated glass and the nature of the formed crystallites was studied by XRD The mechanical properties of this glass are also compared to results previously obtained in the case of other zirconium-based bulk metallic glasses. (C) 2009 Elsevier B V. All rights reserved.