Structural and rheological properties of CuZrAl metallic glasses under pressure preloading

Abstract

Pressure treatments have been shown to promote rejuvenation in metallic glasses (MGs). In this work, pressure preloading was applied to explore structural and rheological properties of Cu50−xZr50−xAl2x MGs by means of molecular dynamics simulations. Al species directly affected the rejuvenation degree: larger Al contents decreased the variation of potential energy, induced smaller atomic volumes, and increased the apparent viscosity. Bond connectivity analysis revealed that, in Al-rich MGs, high centrosymmetric Voronoi polyhedra tended to be more clustered, affecting the MG response to external stress. In addition, MGs rejuvenated at pressures below 10–20 GPa exhibited Herschel–Bulkley plastic flow, while samples rejuvenated at larger pressures displayed Bingham plastic flow and presented a lower apparent viscosity. These results provide new insights on the relationship between species contents, rejuvenation pressures, and the plastic flow, which can help in the construction of MGs with tailored properties.