石墨烯增强铜钨合金触头耐磨损性能的分子模拟

Molecular Simulation of Anti-abrasion Property of Graphene-reinforced Copper-tungsten Alloy Contacts

石墨烯(graphene,Gr)因其优异的性能而被广泛作为金属基材料增强相,但目前石墨烯对铜钨合金(Cu W)耐磨损性能的微观作用机制仍不清晰。该文基于分子动力学模拟方法,针对Cu W“假合金”的特点,应用粒子群算法建立Cu W80和掺杂不同质量分数石墨烯的CuW80Gr复合模型。基于该模型在LAMMPS下计算温度300~3000K范围内的弹性模量,通过纳米压痕模拟计算模型的硬度,从微观位错动态演变过程分析石墨烯对Cu W80Gr复合模型耐机械磨损性能的增强机制。结果表明:Cu W80Gr模型的弹性模量与硬度均比Cu W80高,且均表现出随着石墨烯质量分数增大而降低的趋势,石墨烯的引入有助于解决断路器在开断关合过程中由于高温引起的机械性能下降问题,石墨烯对CuW复合材料的增强机制为屏障作用与位错强化。研究结果可为铜钨合金复合材料的掺杂优化设计、遴选与性能调控提供理论指导和技术支撑。

Graphene(Gr)is widely used as the reinforcing phase of metal-based materials due to its excellent properties,but the mechanism of the microscopic effect of graphene on the wear resistance of copper-tungsten alloy(CuW)is still unclear.In this paper,based on the molecular dynamics simulation method,the particle swarm algorithm is applied to establish the composite models of CuW80 and different mass fractions of graphene-doped CuW80Gr for the characteristics of CuW“pseudo-alloys”.According to the models,the elastic moduli in the temperature range of 300~3000K are calculated via LAMMPS,the hardness of the models is calculated by nanoindentation simulations,and the enhancement mechanism of graphene on the mechanical abrasion resistance of CuW80Gr composite models is analyzed from the dynamic evolution of microscopic dislocations.The results show that the elastic modulus and hardness of CuW80Gr model are higher than those of CuW80,and they both show a tendency to decrease with the increase of graphene mass fraction.The addition of graphene contributes to solve the problem of mechanical property degradation caused by high temperature during the opening and closing of the circuit breaker,and the strengthening mechanism of graphene on CuW composites is barrier effect and dislocation strengthening.This study can provide theoretical guidance and technical support for the doping optimization design,selection,and performance control of copper-tungsten alloy composites.