【作者】 刘瑞华；

【导师】 宋克兴； 徐晓峰；

【作者基本信息】 河南科技大学 ， 材料加工工程， 2008， 硕士

【摘要】 随着高速电气化铁路的不断发展,要求铜合金接触导线不仅具有较高的导电性和机械性能,而且还应具有优良的耐磨性能和较高的抗软化性能。Al₂O₃/Cu复合材料因具有优良的高强度高导电性能以及抗高温软化性能而成为备受瞩目的一种工程材料。本文以内氧化法制备Al₂O₃/Cu复合材料为研究对象,采用内氧化工艺制备了不同Al₂O₃含量的Al₂O₃/Cu复合材料。并根据高速铁路对接触导线材料提出的性能要求和Al₂O₃/Cu复合材料的强化机理,设计了三种Al₂O₃/Cu复合材料（Al₂O₃含量分别为0.24wt%、0.40wt%和0.60wt%）。对不同Al₂O₃含量的Al₂O₃/Cu复合材料的导电率、硬度及抗拉强度进行测试,并将制备的Al₂O₃/Cu复合材料及Cu-0.36Cr-0.06Zr合金在自制的磨损试验机上进行电滑动摩擦磨损试验,研究了有无载流条件下电流、速度和接触压力对接触导线磨损率的影响。利用扫描电子显微镜（SEM）和能谱仪（EDS）对接触导线磨损表面及纵剖面进行微观组织分析并探讨其磨损机理,为Al₂O₃/Cu复合材料在电滑动领域的工程应用提供理论依据。主要得到以下结论:采用内氧化法制备的0.24Al₂O₃/Cu、0.40Al₂O₃/Cu和0.60Al₂O₃/Cu三种复合材料的导电率分别为:93%IACS、89%IACS和85%IACS;抗拉强度分别为:530MPa、585MPa和607MPa;硬度分别为:152HV、165HV和178HV。其综合性能优良,能够满足高速电气化铁路用接触导线的基本性能要求。电滑动摩擦磨损试验结果表明:相同试验条件下,Al₂O₃/Cu复合材料的抗摩擦磨损性能明显优于Cu-0.36Cr-0.06Zr合金,且0.40Al₂O₃/Cu和0.60Al₂O₃/Cu的耐磨性更加优越。在试验范围内,四种接触导线材料的磨损率均随着电流、滑动时间的增加而增加。电流对0.40Al₂O₃/Cu和0.60Al₂O₃/Cu的影响不明显,对0.24Al₂O₃/Cu和Cu-0.36Cr-0.06Zr磨损率的影响较显著。0.24Al₂O₃/Cu和Cu-0.36Cr-0.06Zr合金的磨损率随电流强度的增长率均较0.40Al₂O₃/Cu和0.60Al₂O₃/Cu的大;在电滑动摩擦磨损试验过程中,随着时间的延长,0.40Al₂O₃/Cu和0.60Al₂O₃/Cu的磨损寿命较Cu-0.36Cr-0.06Zr合金的磨损寿命将呈现出越来越明显的优越性。在试验范围内相同参数条件下,随着Al2O3含量的增加,复合材料的磨损率逐渐降低,材料的抗磨损性逐渐增强,即0.40Al2O3/Cu和0.60Al2O3/Cu明显优于0.24Al2O3/Cu的耐磨性能。在有电流存在时,0.60Al2O3/Cu的抗耐磨性更加明显。Al2O3/Cu复合材料在无加载电流条件下磨损机制主要为粘着磨损和磨粒磨损;在载流条件下磨损机制主要为粘着磨损、磨粒磨损、氧化磨损和电烧蚀磨损,且随加载电流的不断增加,粘着磨损程度加重,Al2O3/Cu复合材料表面的粘着物主要来自于铜基粉末冶金滑块。Cu-0.36Cr-0.06Zr合金在无载流时磨损机制主要为粘着磨损、磨粒磨损和氧化磨损;有载流时磨损机制主要为粘着磨损、磨粒磨损、氧化磨损和电烧蚀磨损,且随加载电流的不断增加,氧化磨损和电烧蚀磨损呈加剧之势。基于本试验研究,Al2O3/Cu复合材料可满足电气化铁路接触导线的要求。在试验范围内,建议接触导线用A12O3/Cu复合材料中的Al2O3含量在0.40～0.60wt%之间。更多还原

【Abstract】 With the continuing development of high-speed electrified railway, the contact wire demands the copper alloy to have high electrical conductivity and mechanical properties, but also have excellent wear-resisting and high anti-softened properties. Al₂O₃/Cu composite has recently made their debut as potentially viable and attractive engineering materials for industrial applications that require high strength, high thermal- and electrical-conductivity, and high resistance to softening at elevated temperatures. Internal oxidation has been regarded as the most suitable method for Al₂O₃/Cu composite. This paper researches Al₂O₃/Cu composite with different A12O3-content prepared by internal oxidation. Based on the performance requirements by the high-speed railway on the contact wire material and strengthening mechanism of Al₂O₃/Cu composite, three materials containing 0.24wt%Al₂O₃, 0.40wt%Al₂O₃ and 0.60wt%Al₂O₃ separately prepared by internal oxidation were designed, and the electrical conductivity, hardness and tensile strength properties of the composite were tested. The tribological properties with and without current of Al₂O₃/Cu composite were investigated on self-made electrical sliding-wear tester. The influence of current, velocity and load on the wear rate of the composite were studyed by compareing with Cu-0.36Cr-0.06Zr. The morphologies of friction surface and vertical section of the composite were also examined with scanning electron microscopy （SEM） and energy dispersive X-ray spectrum （EDS）, and its abrasion mechanisms were discussed. The research is to explore the engineering applications on electric sliding field for providing theoretical basis about Al₂O₃/Cu composite.The following points are considered as the main conclusions:The Al₂O₃/Cu composites containing 0.24wt%Al₂O₃, 0.40wt%Al₂O₃ and 0.60wt%Al₂O₃ separately prepared by internal oxidation can obtain good integrated properties to meet the performance requirements of the contact wire, and the electrical conductivity reach 93%IACS, 89%IACS and 85%IACS, the tensile strength are 530MPa, 585MPa and 607MPa, and the micro-hardness are 152HV, 165HV and 178HV.The wear resistance of Al₂O₃/Cu composite is superior to that of Cu-0.36Cr-0.06Zr alloy under the same conditions, especially, 0.40Al₂O₃/Cu and 0.60Al₂O₃/Cu. The wear rate of all the materials under investigation increases with the increasing of current and sliding time under certain load. And the influence of current on wear rate is not obvious for 0.40Al₂O₃/Cu and 0.60Al₂O₃/Cu, while it is very notable for 0.24Al₂O₃/Cu and Cu-0.36Cr-0.06Zr. Moreover, the growth rate of wear rate of both 0.24Al₂O₃/Cu and Cu-0.36Cr-0.06Zr are higher than that of 0.40Al₂O₃/Cu and 0.60Al₂O₃/Cu. Besides, the service life of wear of 0.40Al₂O₃/Cu and 0.60Al₂O₃/Cu will appear in more and more superiority than the Cu-0.36Cr-0.06Zr alloy with the extending time during the electrical sliding wear processes. The wear rate of Al₂O₃/Cu composite decreases with the increasing of Al₂O₃-content under the same testing. Compared with 0.24Al₂O₃/Cu, 0.40Al₂O₃/Cu and 0.60Al₂O₃/Cu have higher wear resistance under the same conditions.The wear mechanism of Al₂O₃/Cu composite were adhesive wear and abrasive wear without current, while adhesive wear, abrasive wear, oxidation and electrical erosion would be the dominate mechanism under currents. The trend of adhesive wear would be serious with the increasing of current. The adhesions of Al₂O₃/Cu composite come from the copper-based powder metallurgy strip. By comparison, for Cu-0.36Cr-0.06Zr, the wear mechanism were the adhesive wear, abrasive wear and oxidation wear without current, while changed into adhesive wear, abrasive wear, oxidation and electrical erosion with current. Moreover, oxidation and electrical erosion were become more and more severe with the increasing of current.Based on the experimental study, Al₂O₃/Cu composite prepared by internal oxidation meets the performance requirements of the contact wire, and the Al₂O₃-content of Al₂O₃/Cu composite contact wire is 0.40～0.60wt%.更多还原