Investigation of nanomechanical properties of Al/Ni and Ni/Al nanomultilayers under nanobending using molecular dynamics simulation

The mechanical properties and mechanics of aluminum/nickel (Al/Ni) and Ni/Al multilayers under the three-point nanobending test are studied using Molecular Dynamics (MDs) simulations based on the many-body tight-binding potential. The effects of the thickness of individual layers and temperature are evaluated in terms of molecular trajectories, loading force, adhesion force, von Mises stress, slip vectors, and elastic recovery ratio. Simulation results show that the bending angle of a multilayer increases with decreasing hardness of its surface layer. Alloying phenomena occur frequently on a deformed multilayer whose surface layer hardness is much higher than that of the layer below. The internal stress of a multilayer increases with increasing indentation depth and temperature, and the required loading force and the adhesion force decrease with increasing temperature. For multilayers with a thickness of only several nanometers, the variation of mechanical strength with increasing number of layers (decreasing thickness of layers) mainly depends on the hardness ratio of the surface layer to the layer below. The elastic recovery increases with increasing atomic bonding energy and temperature.