How does the structural inhomogeneity influence the shear band behaviours of metallic glasses

ABSTRACT

Here we propose a model to understand the influence of structural inhomogeneity on the shear band behaviours of metallic glasses. By considering the inhomogeneous structure and stress concentration, the model predicts that the strain for shear band nucleation in metallic glasses can be variable and far below the theoretical elastic limit. During sliding, the shear band will approach a dynamic equilibrium state of balanced free volume generation and annihilation. By considering the accumulation of irreversible structure change, the shear band will finally develop into fracture. Under fluctuating load, the shear band shows an ‘activate-arrest’ behaviour, which results from a delayed response to the external load change. These results reasonably explain and correlate the physics behind the elastic limit, stick-slip shear band behaviour, implicit shear events, and shear band fracture in metallic glasses. The study can provide another perspective and platform to understand the correlations between structural inhomogeneity and shear band behaviours in metallic glasses, and further explore other shear band related phenomena not only in metallic glasses but also in the class of shear-softened materials.

KEYWORDS:

• Metallic glasses
• shear bands
• free volume
• plastic deformation
• structural inhomogeneity

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work is supported by the National Natural Science Foundation of China [grand number 51871129, 51771096 and 51571127]; the General Research Fund (GRF) of the Hong Kong Government [grant number CityU11209314, CityU102013] and the Fostering Talents Foundation of Guangdong University of Technology [grant number 262511006].