碳纳米管增强Cu-Ti复合材料及其界面的研究

发布时间：2018-03-22 04:23

本文选题：碳纳米管　切入点：复合材料　出处：《昆明理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：碳纳米管(CNTs)与具有众多独特优点,实验和理论计算均表明CNTs具有极高的力学性能,优异的导电和导热性能。因此自CNTs被发明以来一直是复合材料理想的增强相之一,目前CNTs及其复合材料的研究己成为一个极为重要的研究领域。CNTs作为一种理想的增强相,实验中表现出极高的弹性模量(270-950 GPa)以及抗拉强度(11-63 GPa)。然而在实际制备的复合材料中,不同工艺制备的CNTs增强Cu复合材料的性能存在较大差异,但通常难以充分发挥CNTs的性能。本试验基于粉末冶金方法制备了碳纳米管增强铜-钛基复合材料,利用高能球磨发制备了片状复合粉末。利用放点等离子烧结制备了 CNTs增强Cu-Ti基复合材料。对复合材料采用SEM、EDX分析试样表面形、微观结构以及元素组成。测试了其拉升强度。采用阿基米德排水测试密度。通过TEM研究了界面的微观结构,研究了界面处碳化物的形成,以及其在基体中的位向关系。对这些数据分析后得到结论如下:1通过酸化处理制备的碳纳米管表面存在大量缺陷,这一缺陷的存在有效的诱导了碳化物在CNTs表面形成。2碳化物的形成使得Ti扩散至Cu/CNTs界面区域,减少了 CNTs和基体间的空隙,能够促进致密的界面的形成,基体和CNTs之间的机械结合。3界面处碳化物的形成,使得Cu基体和CNTs之间形成了有效的过渡层,Cu与碳化钛形成半共格相界。TiC与CNTs间存在共价键结合。这增加了 Cu基体与CNTs之间的界面结合强度,使得应力能够很好的传递至增强相中。4由于基体与碳纳米管不同的热膨胀系数,使得冷却过程中,基体与碳纳米管之间产生应力,促使TiC和Cu基体生成大量小角度晶界,提高了界面对位错的承载能力,提高了小范围内基体的塑性。5当碳管含量增加时,形成团聚的可能性增加,烧结过程中,由于时间较短,Cu和Ti不足以扩散至碳管团聚体的内部填充间隙,导致材料内部容易形成裂纹,这使得含有高质量分数碳管的的复合材料塑性和强度下降。
[Abstract]:CNTs has many unique advantages. Both experimental and theoretical calculations show that CNTs has excellent mechanical properties, excellent conductivity and thermal conductivity. Therefore, CNTs has been one of the ideal reinforcements for composites since its invention. At present, the research of CNTs and its composites has become a very important research field. As an ideal reinforcement phase, the experimental results show very high elastic modulus (270-950 GPA) and tensile strength of 11-63 GPa.However, in the practical composites, The properties of CNTs reinforced Cu composites prepared by different processes are quite different, but it is usually difficult to give full play to the properties of CNTs. In this experiment, carbon nanotubes reinforced copper-titanium matrix composites were prepared based on powder metallurgy. The flake composite powder was prepared by high energy ball milling, and the CNTs reinforced Cu-Ti matrix composites were prepared by plasma sintering at the point of discharge. The surface shapes of the composites were analyzed by means of SEM edX. Microstructure and elemental composition. Tensile strength was measured. Archimedes drainage density was used. Microstructure of the interface was studied by TEM, and the formation of carbides at the interface was studied. After analyzing these data, it is concluded that there are a lot of defects on the surface of carbon nanotubes prepared by acidizing treatment. The existence of this defect effectively induces the formation of 2.2-carbides on the surface of CNTs, which makes Ti diffuse to the interface area of Cu/CNTs, reduces the void between CNTs and matrix, and can promote the formation of dense interface. The formation of carbides at the interface of mechanical bonding between matrix and CNTs, The formation of an effective transition layer between Cu matrix and CNTs leads to the formation of a semi-coherent phase boundary between Cu and titanium carbide. Tic and CNTs are covalently bonded, which increases the interfacial bonding strength between Cu matrix and CNTs. As a result of the different thermal expansion coefficient between the matrix and the carbon nanotube, the stress between the matrix and the carbon nanotube is produced during the cooling process, which leads to the formation of a large number of small angle grain boundaries between the TiC and Cu matrix. The bearing capacity of interfacial dislocation is improved, and the plasticity of matrix in a small range is improved. When the content of carbon pipe increases, the possibility of forming agglomeration increases, and during the sintering process, Because the short time of Cu and Ti is not enough to diffuse into the inner filling gap of carbon tube aggregates, it is easy to form cracks inside the material, which results in the reduction of plasticity and strength of the composite containing high mass fraction carbon tube.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB333

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