Probing the role of Johari–Goldstein relaxation in the plasticity of metallic glasses

Abstract

Johari–Goldstein (JG) relaxation closely relates to the shear transformation zones (STZs) in the flow of metallic glasses (MGs). However, the actual role played by JG relaxation in the STZ-evoked plastic deformation of MGs remains unknown. In this work, by substituting the transition metal (TM) element in La(TM)Al MGs (TM = Ni, Co, Cu, CuNi) to tune the feature of JG relaxation, how JG relaxation alters the deformation behaviors of MGs is tentatively examined with nanoindentation. The results demonstrate that JG relaxation modulates the anelastic to plastic transition rate in the plastic deformation accommodation of MGs via a characteristic relaxation time.

Keywords

• Metallic glasses
• Johari–Goldstein relaxation
• plasticity
• nanoindentation