Unexpected creep behavior in a rejuvenated metallic glass

Authors：Wu, J. P.; Lin, Y.^*; Duan, F. H.; Chen, Q.; Wang, H. T.; Li, N.; Wen, J. L.; Pan, J.^*; Liu, L.

Source：JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY, 2023, 163: 140-149.

DOI：10.1016/j.jmst.2023.04.020

• Metallic glass
• Energy state
• Rejuvenation
• Creep
• Strain-hardening

Rejuvenation, bringing metallic glasses (MGs) to the younger and higher energy states, provides an alter-native avenue to explore the interplay between the property and microstructures of MGs. In this study, the creep behavior of the Zr69.5Cu12Ni11Al7.5 MGs was experimentally examined by controlling the en-ergy state in terms of structural rejuvenation and thermal annealing. It is found that compared to the as-cast counterpart, the annealed MG at a lower energy state exhibits a higher hardness, a smaller dis-placement, and a lower creep rate due to the decreased free volume and the inhibited activation of the shear transformation zone. Conversely, the rejuvenated MG at a high energy state displays lower hardness and increased free volume content, yet it demonstrates superior creep resistance compared to its as-cast counterpart, which deviates from conventional understanding. This unexpected phenomenon occurs as the initial high-content free volume annihilates during creep, and strain hardening takes precedence over strain softening as the prevailing process during creep deformation, leading to a superior creep perfor-mance in extremely rejuvenated MGs.& COPY; 2023 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

• Institution
  中国科学院; 华中科技大学; y