Strengthening effects of indentation notches on metallic glasses and their sensitivity to stress triaxiality

• A novel method of cyclic compression of the lever was developed to create indentation ring notches in cylindrical metallic glass. • Plastic deformation of notched metal glass under triaxial compression first occurs on the outside of the notch and expands toward the center to form a V-shaped shear zone. • Indentation notched metallic glass can further improve the strength and plasticity of metallic glass due to the reinforcement at the notch, but shows extreme sensitivity to stress triaxiality. In this study, a metallic glass sample with an annular indentation notch was successfully constructed by a compression rod cyclic compression strategy using molecular dynamics simulation, and the mechanical behaviors of cut-notched metallic glass samples with the same stress triaxiality and notch size under triaxial compression were comparatively analyzed. It is found that the indentation notch further improves the strength and plasticity of the metallic glass, while it is insensitive to the cut-notched metallic glass with the same notch size. During triaxial compression, rejuvenation and shear softening lead to an increase in free volume, while diffusion and residual compressive stresses lead to a decrease in free volume. The stress triaxiality plays a key regulatory role in their competition and affects the final state of free volume change. This study provides a new theoretical basis and process idea for the enhancement of strength and plasticity of metallic glass.