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原料Cu,Nb和石墨粉末置于高能振动盘式研磨仪,在氩气气氛中研磨7 h制备Cu-5%NbC(体积分数)粉末。采用两步压制法及在真空900℃烧结1h条件下制得Cu-NbC功能梯度材料和复合材料样品,研究样品的显微组织、物理性能和力学性能。场发射扫描电镜、能量色散X射线和X射线衍射结果表明,样品经烧结处理后,晶粒尺寸为18~27 nm的纳米结构基体中含有大小为42 nm的纳米颗粒增强相,证实了所制复合材料的高温热稳定性。Cu-15%NbC复合材料样品的硬度是纯Cu样品硬度的5倍。相对于纯Cu样品,磨损后Cu-15%NbC复合材料样品的体积磨损量减小,且电导率降低至36.68%IACS。相对于复合表面中的复合材料样品,Cu/NbC功能梯度材料样品在具有与复合材料相同的硬度和磨损性能的条件下,显示出75.83%IACS的较高电导率。因此,具有良好力学性能和电学性能的Cu/NbC功能梯度材料将成为很好的电触头材料。
The raw materials Cu, Nb and graphite powders were placed in a high energy vibration disk mill and ground for 5 hours in an argon atmosphere to prepare a Cu-5% NbC (volume fraction) powder. The Cu-NbC functional graded materials and composite samples were prepared by two-step pressing method and sintering under vacuum at 900 ℃ for 1h. The microstructure, physical properties and mechanical properties of the samples were studied. The field emission scanning electron microscopy, energy dispersive X-ray diffraction and X-ray diffraction results show that the nanostructured matrix with size of 42 nm has a nanoparticle reinforcement phase of 42 nm in size after sintering. High temperature thermal stability of composites. The hardness of Cu-15% NbC composite samples is five times that of pure Cu samples. The volumetric wear of Cu-15% NbC composite samples after wearing reduced compared to pure Cu samples, and the electrical conductivity decreased to 36.68% IACS. The Cu / NbC functionally graded material samples showed higher conductivity of 75.83% IACS with the same hardness and wear properties as the composite relative to the composite samples in the composite surface. Therefore, Cu / NbC functional graded material with good mechanical and electrical properties will become a good electrical contact material.