Atomistic simulation of local rearrangements in Ni50Zr50 metallic glasses subjected to compression cycles

Ni50Zr50 metallic glasses were subjected to hydrostatic compression cycles and their atomic scale response investigated by molecular dynamic simulations. Compression cycles consisted of a hydrostatic pressure increase from zero to a maximum value and a successive relaxation of the system back to zero pressure. After each compression cycle, atomic mobility was studied at constant temperature both in the absence and in the presence of shear. It appeared that atomic mobility has cooperative character, with groups of atoms undergoing local rearrangements. The number of such collective displacements decreases as the number of compression cycles increases. In addition, rearrangements in unstrained and strained systems are spatially correlated, involving approximately the same atoms. Such feature has been connected with local structure.