76 / 2024-04-10 20:03:25

Molecular dynamics simulation of mechanical properties of graphene-enhanced copper-tungsten alloy contact

copper-tungsten alloy contact,graphene,mechanical properties,molecular dynamics

As Chinese ultra-high voltage AC/DC transmission and transformation systems continue to develop towards higher voltage levels, the existing copper-tungsten alloy electrical contacts have difficulty meeting the mechanical performance requirements of higher voltages, especially in the closing process of circuit breaker contacts. Due to the high-energy arc action, the contacts experience temperature rise, local softening, melting, or even splashing, resulting in more severe post-arc friction and wear, leading to eventual failure of the contacts after multiple closings. Therefore, improving mechanical performance of contacts has become an urgent problem to be solved. Graphene is a two-dimensional material with unique crystalline characteristics, which has attracted extensive attention in the field of reinforced composite materials due to its excellent electrical, thermal, and mechanical properties. Compared with carbon nanotubes with similar intrinsic properties, graphene has a larger specific surface area, which can better enhance the performance of metal-based composite materials. In this study, aiming at the special "pseudo-alloy" structure of copper-tungsten alloy, a composite model of copper-tungsten alloy containing graphene with different mass fractions was constructed based on molecular dynamics simulation. The elastic modulus within the temperature range of 300 K to 3000 K was calculated based on this model to explore the effect of graphene mass fraction on the mechanical properties of the composite material. The results show that the bulk modulus, Young's modulus, and shear modulus of the model doped with graphene are higher than those of CuW80 at each temperature. Taking 0.15wt% graphene doping as an example, at 300 K, the bulk modulus, Young's modulus, and shear modulus of CuW80Gr increased by 41%, 57%, and 60% respectively, while at 3000 K, the bulk modulus, Young's modulus, and shear modulus of CuW80Gr increased by 47%, 99%, and 106% respectively. Moreover, all moduli show a decreasing trend with the increase of graphene mass fraction. The introduction of graphene helps to solve the problem of mechanical performance degradation of circuit breakers due to high temperature during opening and closing processes, and improves the wear resistance of composite materials.