Atomic simulations of plastic deformation mechanism of MgAl/Mg nanoscale amorphous/crystalline multilayers

Abstract

The deformation behavior of MgAl/Mg nanoscale amorphous/crystalline multilayers (NACMs) with equal layer thicknesses of amorphous and crystalline phases under tension loading is investigated by molecular dynamics simulation method. The results show that the plastic deformation mode of NACMs changes from cross generalized shear bands dominated deformation to finally single shear band plastic deformation with the increase of layer thickness, and the plastic deformation of NACMs with medium layer thickness is realized through cooperative interactions among crystalline layer, amorphous layer and amorphous/crystalline interfaces (ACIs), which could be treated as a transition progress. The results indicate that the peak stresses of the NACMs are greater than that of monolithic amorphous regardless of layer thickness, which is likely to result from the increase of the strong crystalline phase and the strengthening effect of the ACIs. The results also reveal that the ductility and strength of NACMs could be improved effectively by choosing the appropriate layer thickness. In addition, the deformation behavior of NACMs is also quantificationally disclosed and analyzed in current study.