Change dynamic behaviors by heightening its stored energy of monolithic bulk metallic glass

Abstract Bulk metallic glasses (BMGs) are usually brittle, and show serious negative strain rate sensitivity upon dynamic loading due to no sufficient time for generation of the shear bands, which fatally limit their practical applications. Investigations have been done on BMGs dynamic deformation behaviors, but in which yielding phenomenon was hardly reported before. In this work, by raising stored energy which appears as an exothermic heat of relaxation on heating the glass, the dynamic and quasi-static deformation behaviors of Cu 45.75 Zr 46.75 Al 6.5 Co 1 BMG were explored. We found that, compared the BMG at higher energy state with the as-cast BMG, its quasi-static compressive plasticity is improved from 0.9% to 3.3%. Additionally, more meaningfully, under dynamic compression, an evident yield plateau appears on the stress–strain curves of all the treated specimens at different strain rates, also the typical negative strain rate sensitivity of BMG ultimate strength weakens significantly. Other results reveal that raising BMGs stored energy can bring their spatial heterogeneity enhancement which distinctly proliferates shear bands in deformation, thus avoids rapid spread of limited shear bands catastrophically. This work provides an efficient way to improve BMGs dynamic properties and may shed light on their dynamic behaviors.