Cold-Welding Mechanism and Tensile Behaviors of Cu–Al Nanowires: A Molecular Dynamics Simulation

The technology of welding heterobimetallic nanowires (NWs) at the nanoscale is of importance for the fabrication of optoelectronic devices. In this work, molecular dynamics simulations are performed to simulate nanojoining of Cu and Al NWs by head-to-head cold-welding as well as tensile properties of obtained welding joints. The results of the climbing image nudged elastic band calculations show that Cu and Al NWs can be successfully connected by cold-welding with high-efficiency and few defects, owing to recrystallization and interfacial diffusion of atoms. Moreover, pressure, temperature, and welding velocity will exert significant influence on tensile properties of joints, including strength and plasticity. The tensile test shows that the fracture usually occurs on the Al NWs rather than the joints of the Cu–Al NW, which demonstrates the high quality of joints. Simulation results obtained in this work will provide atomic scale insights into the cold-welding of heterobimetallic NWs and helpful theoretical guidance for the application of nanojoining.