铝和碳化硅颗粒增强铜基自润滑复合材料的制备及性能研究

发布时间：2018-02-03 01:04

本文关键词： 铜基自润滑复合材料组织结构 Al含量 SiC含量摩擦磨损性能　出处：《西南交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：铜基自润滑复合材料具有良好的导电、导热和耐磨性能,常被用作为制动闸片、接地装置等。降低铜基复合材料的生产成本与提高其服役性能具有极为重要的意义。本文通过冷压-烧结-复压工艺制备了不同Al、β-SiC含量的铜基自润滑复合材料,研究Al含量对Cu/Gr(石墨)复合材料及SiC含量对(Cu-9.5wt%Al)/Gr复合材料的组织结构、力学性能、物理性能、摩擦磨损性能和耐蚀性能的影响。向铜基复合材料中添加Al时,将首先在铜基体中形成α-Cu固溶体,Al含量达到7.6 wt%时析出了少量γ2硬脆相,Al含量为9.5 wt%时基体中析出大量γ2相并成网状分布;向复合材料中添加β-SiC颗粒时,将在铜基晶界处产生大量团聚,SiC含量越高,团聚现象越显著。Al的添加使复合材料获得了较高的宏观硬度、基体显微硬度、抗弯强度和抗压强度,复合材料的相对密度在Al含量为5.7 wt%时达到最高值,其导电性能和塑性随Al含量增大而不断减低;SiC颗粒的添加使复合材料的宏观硬度、相对密度、电导率、抗弯强度、抗压强度和塑性降低,其基体显微硬度在SiC含量为4 wt%时达到最大值,为210.9 HV。在干摩擦条件下,随Al含量增大,摩擦系数不断降低,磨损率呈先增加后减小的趋势,Al含量为9.5 wt%时复合材料具有良好的耐磨性;随SiC含量增大,摩擦系数逐渐增加,磨损率呈先增加后减小的趋势,SiC含量为0wt%与6 wt%时复合材料具有较好的耐磨性能。在湿摩擦条件下,随Al含量增大,摩擦系数先减小后增加,磨损率不断降低,Al含量同样为9.5 wt%时复合材料具有良好的耐磨性能;随SiC含量增加,摩擦系数先减小后增加,磨损率则不断降低,SiC含量为6 wt%时复合材料具有较好的耐磨性能。且相比于干摩擦,湿摩擦时的摩擦系数与磨损率均较高。在5%H_2SO_4溶液中,Al含量为9.5 wt%时复合材料具有良好的耐蚀性能,β-SiC颗粒的添加将使复合材料的耐蚀性能减弱。
[Abstract]:Copper-base self-lubricating composites have good electrical conductivity, thermal conductivity and wear resistance, and are often used as brake pads. It is very important to reduce the production cost and improve the service performance of copper matrix composites. In this paper, copper matrix self-lubricating composites with different contents of Al, 尾 -SiC were prepared by cold pressing, sintering and repressing process. The effects of Al content on the microstructure, mechanical properties, physical properties, friction and wear properties and corrosion resistance of Cu / Gr-graphite composites and SiC content on Cu-9.5wtAl / Gr composites were studied. When 伪 -Cu solid solution Al content reached 7.6 wt% in copper matrix, a large amount of 纬 2 phases were precipitated in the matrix when the content of 纬 2 hard brittle phase was 9.5 wt%, and the 尾 -SiC particles were added to the composites. The higher the amount of agglomerated sic at the grain boundary of copper matrix is, the more obvious the agglomeration phenomenon is. The addition of Al makes the composites obtain higher macro hardness, matrix microhardness, flexural strength and compressive strength. The relative density of the composites reaches the highest value when the Al content is 5.7 wt%. The conductivity and plasticity of the composites decrease with the increase of Al content. The macrohardness, relative density, electrical conductivity and bending strength of the composites are decreased with the increase of Al content. With the decrease of compressive strength and plasticity, the microhardness of the matrix reaches the maximum value of 210.9 HV when the content of SiC is 4 wt%. Under dry friction conditions, the friction coefficient decreases with the increase of Al content. The wear rate increased first and then decreased, and the friction coefficient increased with the increase of SiC content, and the wear resistance of the composite was better when the Al content was 9.5 wt%. The wear rate increased firstly and then decreased. The friction coefficient of the composites decreased first and then increased with the increase of Al content under wet friction condition, when the content of sic was 0 wt% and 6 wt%, the wear resistance of the composites was better. The friction coefficient of the composites decreases first and then increases with the increase of SiC content when the wear rate decreases continuously and the content of Al is also 9.5 wt%. On the other hand, the wear rate of the composites decreases continuously when the content of sic is 6 wt%, and the composites have better wear resistance compared with the dry friction. The friction coefficient and wear rate of the composites are higher during wet friction. The composites have good corrosion resistance when the Al content is 9.5 wt% in 5H _ 2SO _ 4 solution, and the corrosion resistance of the composites will be weakened by the addition of 尾 -SiC particles.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB33

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