碳纤维增强铜基复合材料的界面行为及其对性能的影响

Cu base composites are considered to have great potential in application as a novel kind of advanced material due to combinations of high strength, conductivity, thermal conductivity similar to pure Cu, and good erosion resistance to electricity arc as well as excellent wear resistance. One of the most important applications is the Cu base self-lubrication composite fabricated by adding solid lubricant into Cu alloy matrix. C(F)/Cu composite specially is always the priority for the electric contacts and brush materials, but the interface between the C and the Cu matrix exists in the form of mechanical bonding, this kind of low bonding strength often leads to the enforcement pulling out and falling out. Therefore, the improvement of strength, hardness and wear resistance has been the central task for the research and development of Cu base materials..This project means to synthesize the copper matrix composites reinforced with graphite and carbon fiber by mechanical alloying, composite plating and spark plasma sintering (SPS), and study on the crucial basic theoretic issues during preparation process, including: ① the wetting theory and interfacial characteristic; ② the development regularity of the interfacial structures at all levels during the densification of the C(F)/Cu composites sintering; ③ the disciplinarian of the match between interfacial characteristic and mechanical property. The major goals of this project are: ① to reveal the wetting dynamic mechanism of plating and the interfacial characteristic during the surface treatment of the carbon fiber; ② to investigate the morphology of the "coppered carbon" in saturated solid solution and propose a new method to improve the wettability of the C/Cu; ③ to explore the microstructure and the change of the interfacial structure under the pulse current, and to reveal the intrinsic mechanism of the effect of the different densification styles on the interfacial combination and the mechanical property; ④ to establish an inherent relationship between interfacial microstructure and mechanical property, electrical property and friction and wear property, and thus reveal the essence of the material composition and its decisive factor from a micro-level and macroscopic performance perspective. Based on that, this project will propose the mechanism of the mechanical activation and the electric field discharge activation under the pulse current, which will lay the necessary theoretical groundwork for the development of the metal-matrix composites reinforced with fiber and the new preparation technology.

本项目通过机械合金化、复合镀和放电等离子烧结技术合成碳纤维增强的石墨/铜基复合材料，研究制备过程中的关键基础理论问题，包括：① Cu与C（CF）之间的润湿原理与界面行为；② 烧结致密化过程中各级界面结构演变规律；③ 界面行为与性能匹配的规律等。达到的目标：① 揭示碳纤维表面处理过程中镀层润湿动力学机制和界面结合特征；② 研究过饱和固溶体"铜包碳"形貌，提供改善C/Cu界面润湿性的新方法；③ 探索脉冲电流作用下组织状态和界面结构的演变行为，揭示不同致密化方式影响界面结合的内在机制，及其对材料性能的影响规律；④建立起微观的界面特征与力学性能、电学性能和摩擦磨损性能之间的内在联系，从微观层次和宏观性能的角度揭示出材料复合的本质及其决定因素。并在此基础上，提出机械激活和脉冲电流作用下电场放电激活的双重激活作用机制，为发展先进的纤维增强金属基复合材料及其制备新技术奠定必要的理论基础。

铜基复合材料具有很高的强度、接近于纯铜的导电导热性、良好的抗电弧烧蚀能力和摩擦学性能，因此作为一种新型的先进材料具有很高的应用潜力。由于碳(石墨、碳纤维)和铜固溶度极低的特性，人们对其界面的润湿性和界面结合特征了解甚少，这在一定程度上阻碍了铜基复合材料的开发。本项目深入研究了碳纤维与铜、铜合金镀层的润湿性和界面结合特征；研究了过饱和固溶体“铜包碳”形貌，寻求改善C/Cu界面润湿性的新方法；探索了脉冲电流作用下组织状态和界面结构的演变行为；揭示了在双重激活机制(机械力作用下机械激活作用和脉冲电流作用下的电场的放电激活)作用下C(F)/Cu复合材料界面特征及其对材料三方面性能(强度、摩擦磨损、导电性)的影响规律。本研究不仅有助于丰富人们对于金属－碳润湿性及其界面结构的认识，而且对于铜基复合材料的开发也有积极的指导意义，将为高性能铜基减摩耐磨复合材料的设计提供理论基础。