As-cast Zr-Ni-Cu-Al-Nb bulk metallic glasses containing nanocrystalline particles with ductility

Bulk metallic glasses (BMGs) exhibit inhomogeneous deformation under loading at room temperature due to the formation of highly localized shear bands, which leads to a catastrophic failure. We present recent advances in the processing technique, and in the further understanding of the relationship between the microstructure and mechanical behavior of Zr-based BMG composites (BMGCs). By adding Nb to Zr-Ni-Cu-Al, nanocrystalline-particle-containing BMGCs were synthesized in an as-cast condition without subsequent heat treatments. High-resolution transmission electron microscopy results show that the addition of 2 atomic percent (at.%) Nb introduces nanocrystals with an average size in the range of 1-3 nm. Differential-scanning calorimetry and differential-thermal analyses indicate that the glass-forming ability increased after adding Nb. The compressive plasticity of the Nb-containing BMGC at room temperature is significantly improved (about 3%), when compared to the monolithic BMGs (about 0.1-0.3%) with an increase in the compressive strength from 1820 to 1860 MPa