Deformation dynamics of NiZr metallic glass during nanoindentation: An atomistic approach

Abstract

In this study, the deformation mechanisms of Ni50Zr50 metallic glasses (MGs) are investigated using molecular dynamics simulations of nanoindentation. The effects of indentation depth, temperature, velocity, and indenter diameter on shear transformation zones (STZs), forces, hardness, and pile-up are explored. Plastic deformation is dominated by STZs, which expand and strengthen with increasing indentation depth, leading to higher strain localization, pile-up, and a consequent increase in hardness (ranging from 6 to 10.5 GPa at higher indentation depth). Higher velocities lead to increased strain, reduced relaxation, increased STZs, higher indentation forces, and hardness. Conversely, higher temperatures cause thermal softening, resulting in a decrease in forces and hardness (reducing to 5 GPa at 700 K) and facilitating atomic mobility and increased pile-up. Smaller indenter diameters cause stress concentration, resulting in higher hardness and higher shear localization, while larger diameter indenters cause deformation distribution, resulting in lower hardness but larger STZs. These findings provide atomic-scale insights into STZ-mediated plasticity and help in designing high-performance Ni50Zr50 MGs for high-velocity and varying-temperature conditions. © 2026 Elsevier B.V.