Deformation behavior and strengthening mechanism of CuTa/CuTa amorphous/amorphous nanomultilayers

The tensile deformation behaviors of Cu80Ta20/Cu20Ta80 amorphous/amorphous nanomultilayers (AANMs) are investigated using molecular dynamics simulation. The tensile strength of the AANMs shows that the AANMs with reduced layer thickness from 160.0 angstrom to 26.7 angstrom demonstrate the Hall-Petch relationship because of the obstruction of interface to the shear band movement, while the specimens with more reduced layer thickness from 26.7 angstrom to 10.0 angstrom manifest the inverse Hall-Petch effect due to the direct interaction of the shear trans-formation zones. Additionally, the tensile strength of AANMs increases with increasing the strain rate and decreasing the temperature. The deformation mechanism reveals that multiple shear bands cross the amorphous/ amorphous interfaces and interact with each other, which leads to enhanced ductility of the specimen with a small layer thickness. However, the shear bands locally focus on soft amorphous layers for AANMs with great layer thicknesses, causing shear softening and sample damage.