The Decoupling of Hardness and Elastic Modulus in Ti-Based Metallic Glasses Induced by Elastic Pretreatment

In this paper, the elastic precompression method is employed as a pretreatment technique to investigate the evolution and characteristics of the micro-mechanical properties of metallic glasses. Nanoindentation analysis indicates that pre-compression treatment leads to structural rearrangement within the material, which in turn influences the nucleation and propagation of shear bands, resulting in a transition of serrated flow from a step-like to a wave-like pattern under a 400 MPa load held for 75 min. Crucially, precompression triggers a unique "decoupling" response: hardening alongside elastic softening. Further, this structural evolution is evidenced by the shear transition zone volume calculated using the jump rate method. The shear transition zone volume exhibits a nonlinear trend, initially increasing and then decreasing with increasing compressive strength and holding time, which reflects the kinetic competition mechanism between local shear instability and coordinated atomic rearrangement that arises under precompression. This study elucidates the effect of elastic precompression treatment on the micromechanical properties of a Ti-based metallic glasses, providing a reference for the optimization of plasticity in metallic glasses.