Enhanced plasticity in a Ti-Ni-Nb-Zr shape memory bulk metallic glass composite with high Nb addition

In this work, we reported a new Ti-Ni-Nb-Zr bulk metallic glass composite with high Nb addition, which is composed of amorphous, β-Nb and shape memory B2-Ti(Ni, Nb) phases. The volume fraction of the amorphous phase in the rod specimen with a diameter of 1.5 mm was determined to be ～15 vol%. The room-temperature mechanical test suggested that the composite exhibited a significant engineering plastic strain of 22.1% and a maximum compressive strength of ～2400 MPa, together with a dominating strain-hardening behavior during the whole deformation process. The large plasticity of the material was contributed the pile-ups of dislocation and severe lattice distortion, as well as generation of abundant shear bands during deformation. This result provides a promising approach to improve the mechanical properties of metallic glasses through compositional and structural design.