Atomistic insights into thermo-tensile response of CuNi nanowires: uncovering the mechanism of high-temperature performances

Abstract

Cupronickel (CuNi) alloys, renowned for their corrosion resistance and electromechanical performance, hold considerable promise for high-temperature nano-electromechanical (NEMS) devices and applications. This study employs molecular dynamics simulations to elucidate the influence of nickel (Ni) content and temperature on the tensile behaviour of CuNi nanowires (NWs). Simulations were conducted for CuNi NWs using an embedded atom method potential for three global compositions: Cu<inf>90</inf>Ni<inf>10</inf>, Cu<inf>70</inf>Ni<inf>30</inf>, and Cu<inf>50</inf>Ni<inf>50</inf> (mol%) at 300 K. Dislocation analyses revealed composition- and temperature-dependent deformation modes, involving both perfect and partial dislocations. The equiatomic Cu<inf>50</inf>Ni<inf>50</inf> NW displayed the highest yield strength (7 GPa) and Young’s modulus (88 GPa), attributable to enhanced Cu–Ni bonding

however, its ductility was constrained by partial dislocation pinning. To assess thermal effects, the Cu<inf>50</inf>Ni<inf>50</inf> NW was further examined up to 80% of melting point. Increasing temperature markedly diminished its yield strength to 2 GPa and Young’s modulus to 37 GPa at 1100 K. Moreover, in low-Ni-content NWs, the emergence of steeply inclined stacking faults during straining contributed to reduced mechanical strength. These insights furnish a fundamental understanding for the rational design of CuNi NWs to ensure reliable performance in high-temperature applications. © 2025 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.