Mechanical and structural assessment of CuZr metallic glasses rejuvenated by thermal-pressure treatments

Abstract

Thermal-pressure treatments have proved to bring metallic glasses (MGs) to rejuvenated states. However the knowledge regarding their effect on the mechanical properties and atomic structure is still limited. Here, molecular dynamics simulations were performed on Cu50Zr50 MGs rejuvenated at pressures in the range of 0-50 GPa. The Young, bulk, and shear moduli decreased as the pressure increased, while the Poisson's ratio increased. The shear modulus showed the largest variation, with a loss of similar to 8.5%. Compression tests revealed that the transition from localized to homogeneous deformation occurred in the 20-32 GPa range. The contribution of different Voronoi polyhedron types to MGs rejuvenation were also explored. Voronoi analysis delivered that solid-like polyhedra contributed to the increase of potential energy, whereas transition and liquid-like polyhedra contributed to the increase of atomic volume. Overall, our results elucidate the change of several properties at the atomic scale, adding new insights regarding thermal-pressure treatments in MGs.

Thermal-pressure treatments have proved to bring metallic glasses (MGs) to rejuvenated states. However the knowledge regarding their effect on the mechanical properties and atomic structure is still limited. Here, molecular dynamics simulations were performed on Cu50Zr50 MGs rejuvenated at pressures in the range of 0-50 GPa. The Young, bulk, and shear moduli decreased as the pressure increased, while the Poisson's ratio increased. The shear modulus showed the largest variation, with a loss of similar to 8.5%. Compression tests revealed that the transition from localized to homogeneous deformation occurred in the 20-32 GPa range. The contribution of different Voronoi polyhedron types to MGs rejuvenation were also explored. Voronoi analysis delivered that solid-like polyhedra contributed to the increase of potential energy, whereas transition and liquid-like polyhedra contributed to the increase of atomic volume. Overall, our results elucidate the change of several properties at the atomic scale, adding new insights regarding thermal-pressure treatments in MGs.