Yielding transition under oscillatory shear in metallic glasses

The yielding transition of amorphous solids remains a fundamental yet poorly understood issue in materials physics. In this work, we employ oscillatory shear to probe the yielding transition in metallic glasses (MGs) with various thermal histories. We identify three distinct deformation regimes depending on the applied strain amplitudes. Below the yield strain γ_y, the response is elastic and accompanied by aging, through reversible atomic rearrangements that preserve the material’s initial memory of thermal history. Slightly above γ_y, the system undergoes a sharp transition during oscillatory cycles, indicated by a sudden rise in potential energy and non-affine displacement, along with the emergence of a shear band. Well above γ_y, plastic deformation dominates, driving samples of various initial stability toward a common steady state, while thermal histories are erased by irreversible rearrangements and shear band formation. These findings advance the understanding of failure mechanisms in MGs and shed light on tuning their mechanical performance in industrial applications involving cyclic loading.