Mechanical Response of Bulk Metallic Glasses: Investigation by Mechanical Spectroscopy and Compression Tests. Elastic, Viscoelastic and Viscoplastic Components.

摘要

The present paper addresses the mechanical behaviour of several bulk metallic glasses (BMG). Both small and large deformations are investigated, using mechanical spectroscopy and compression tests, respectively. In the case of a given BMG, the influence of temperature and strain rate (or frequency) on the mechanical response exhibits an attractive similarity when either small or large deformations are applied. Equivalence between temperature and time is clearly evidenced. The same behaviour is observed in many BMG, whatever their chemical composition, and therefore whatever their glass transition temperature. This behaviour is also very similar to that reported in other amorphous materials: polymers or oxide glasses. The same physical model enables a good description of this behaviour. It is based on atomic mobility and localized deformation in "soft" zones. Nano-crystallization hinders strongly the atomic mobility and induces a drastic hardening at high temperature.