Consolidation of Ni-Ti Based Metallic Glass and Its Pseudoelasticity After Crystallization

In this study, the use of Ni-Ti-Cu-Zr(-Si) alloy as a metallic glass precursor for a pseudoelastic alloy, following thermoplastic forming, is investigated. The addition of Si enhanced the glass forming ability such that a fully amorphous sample with a thickness of ~450 µm was obtained with Si containing alloy. The addition of Si effectively stabilizes the supercooled liquid by significantly increasing the activation energy of glass transition. The incubation time increased with the addition of Si. The parameters relevant to pseudoelastic effects, such as the maximum indentation depth (D_max) and remnant indentation depth (D_rem), remained almost constant. However, the remnant depth ratio increased slightly with the addition of Si, which means a slight deterioration of pseudoelastic effect. The fabrication of millimeter-scale Ni-Ti-Cu-Zr-Si metallic glass was achieved via the hot pressing of overlapped as-cast plates. Through the study of pseudoelastic alloys using bulk amorphous alloys as precursors, the possibility of expanding the application of pseudoelastic alloys was explored.