Residual stress and elastic recovery of imprinted Cu-Zr metallic glass films using molecular dynamic simulation

Abstract

Molecular dynamics simulations are employed to study mechanistic characteristics of Cu-Zr metallic glasses films during the imprinting process. The influences of punch geometry, loading velocity, temperature, and alloy composition are exhaustively analyzed in terms of imprinting force, deformation characteristic, residual stress, displacement vector, radial distribution function, and elastic recovery ratio. The results show that the imprinting force and the shear transformation zones (STZs) of the Cu50Zr50 MGs films increase, while the residual stress has slightly changed with increasing angle of the punch. In the case of different imprinting velocities, the imprinting force increases. The residual stress also increases in the loading stage; however, it decreases in the unloading stage. The imprinting force, residual stress, highest peak of the radial distribution function (RDF) decrease and movement of atoms become irregular as increasing of temperature. As increasing Cu proportion, the imprinting force increases, the density of atom movement and residual stress increases, while the highest peak of the RDF decreases. The formality of the Cu-Zr MGs films can be improved by increasing Cu proportion and loading velocity, decreasing temperature due to lower average elastic recovery ratio. The imprinting force values are in the range of 100–185 nN, the residual stress values of the loading stage are from 0.44 to 0.82 GPa and the residual stress values of the unloading stage are from 0.4 to 0.9 GPa, the elastic recovery ratio are in the range of 0.17–20.26%.