Rejuvenation mechanism of metallic glass based on stress triaxiality: Synergistic effect of plastic deformation and hydrostatic stresses

RT Wan and ZL Long and YX Cui and LD You, MATERIALS TODAY COMMUNICATIONS, 46, 112813 (2025).

DOI: 10.1016/j.mtcomm.2025.112813

The mechanism of stress triaxiality, as an important feature of triaxial compression, on the rejuvenation of triaxial compression is not clear. In this study, the dual-path regulatory mechanism of stress triaxiality on triaxial compression rejuvenation of metallic glass (MG) is revealed through molecular dynamics (MD) simulations. The design of samples with different notch geometries shows that the plastic deformation time is prolonged under low stress triaxiality, and the hydrostatic compressive stress is widely distributed to drive the atomic potential energy and free volume to increase dramatically, resulting in plasticity enhancement but strength reduction; the deformation rate is accelerated under high stress triaxiality, the localized deformation inhibits the potential energy growth, and the residual compressive stress restricts the expansion of the free volume, resulting in the strength enhancement significantly. The study confirms that hydrostatic compressive stress dominates the structural high-energy state reorganization, while stress triaxiality controls the spatial distribution of free volume by regulating the competitive relationship between residual compressive stress and shear softening, leading to a shift in deformation mode from necking (low triaxiality) to shear banding (high triaxiality). This finding provides a new strategy for toughening MGs based on stress state modulation.

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