Nanoextruded NbTi superconductor nanowires investigated using molecular dynamics simulations

Abstract

The effects of extrusion temperature, extrusion ratio, and workpiece size on the extrusion process of NbTi alloy nanowires (workpieces) are studied using the modified embedded atom method potential. The results are discussed in terms of atomic trajectories, potential energy, extrusion force, and stress. Simulation results show that the workpiece atoms near the ram lose their structural order when the extrusion process begins. The number of disordered atoms gradually increases with increasing ram displacement in order to relax the increasing pressure from the ram. The extrusion force and potential energy increase with increasing temperature. The effect of extrusion ratio dominates the extrusion force once the workpiece atoms start entering the mold opening. A large extrusion force is required for large workpieces with a small extrusion ratio; however, a small workpiece with a large extrusion ratio could lead to high peaks and a large oscillation in the force curve.