Viscoelasticity of metallic, polymeric and oxide glasses: Common features and differences

Present work addresses on mechanical spectroscopy experiments performed on bulk metallic glasses (Zr–Ti–Cu–Ni–Be alloys, Mg–Y–Cu alloys), on oxide glasses (SiO2–Na2O–CaO) and on amorphous polymers (polyethylene terephtalate (PET), nitrile butadiene rubber (NBR), etc.). It appears that whatever the nature of the chemical bonding involved in the material, we observe strong relaxation effects in an intermediate temperature range, near the glass transition temperature. In addition, when crystallization occurs in the initially amorphous material, similar evolution is observed in all the materials. A method is proposed to properly separate elastic, viscoelastic and viscoplastic contributions to the deformation. Finally a physical model is given to describe these viscoelastic phenomena.