Rejuvenation and Malleability Enhancement of Zr-Based Metallic Glass by Sub-Tg Annealing and Cryogenic Thermal Cycle Treatment

(Zr0.6336Cu0.1452Ni0.1012Al0.12)97.4Er2.6 bulk metallic glass (BMG) was prepared by copper mold suction casting, and the effects of sub-Tg annealing and cryogenic thermal cycle (CTC) treatment on its microstructure and properties were investigated. Although the specimens after annealing and CTC treatment did not have significant changes in the amorphous structure, the treated specimens exhibited excellent compressive plastic strain of 16.44 and 19.08%, representing an enhancement of 22.59 and 42.28% compared with the as-cast specimens. The change in plasticity was closely related to the arrangement of atoms and the content and distribution of the free volume caused by sub-Tg annealing and CTC treatment. The corrosion resistance of the specimen was further optimized after sub-Tg annealing and CTC treatment and gradually increased with the increase of annealing temperature and the CTC times. This work demonstrated that appropriate annealing temperature and CTC conditions could be used as an effective and controllable way to modulate the mechanical properties of BMGs.