The anelastic origin of mechanical cycling induced rejuvenation in the metallic glass

Mechanical cycling is one of the effective methods to rejuvenate metallic glasses (MGs) and improve their mechanical properties. The anelastic origin of the rejuvenation by mechanical cycling in a La30Ce30Ni10Al20Co10 MG was investigated via differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). We demonstrate that mechanical cycling promotes the activation of flow defects with short relaxation times, leading to anelastic strains and therefore considerable energy storage, which manifests itself as larger relaxation enthalpy on the DSC curves of MGs. However, the MGs release the excess relaxation enthalpy caused by anelastic strain with time, thus suppressing atomic mobility and elevating & beta; relaxation activation energies. The strategy of mechanical cycling at small strains, as demonstrated in the current work, can expand the energy states of MGs over a wide range of relaxation enthalpies.

Automated summary

Mechanical cycling is an effective method to improve the mechanical properties of metallic glasses. This study investigates the anelastic origin of rejuvenation by mechanical cycling in La30Ce30Ni10Al20Co10 metallic glass using DSC and DMA. The results show that mechanical cycling activates flow defects, leading to anelastic strains and energy storage, which can be observed as larger relaxation enthalpy on DSC curves. However, the excess relaxation enthalpy caused by anelastic strain is released over time, suppressing atomic mobility and increasing β relaxation activation energies. The strategy of mechanical cycling at small strains expands the energy states of metallic glasses.