SPS烧结Cu-Mo-WC电接触材料组织与性能研究

发布时间：2018-07-05 17:30

本文选题：电接触材料 + 放电等离子烧结　；参考：《河南科技大学》2015年硕士论文

【摘要】：Cu-Mo-WC复合材料由于铜能够提供良好的电流导通,高熔点钼能抵抗热熔焊,加入的碳化物颗粒使得材料在保留了铜基体优越的导电性、导热性能的同时,还增加了材料的强度和耐高温稳定性,成为近些年来国内外研究的新型电接触材料。本文采用SPS放电等离子烧结工艺制备出不同WC含量的(Cu-Mo)-WC-0.5%LaCl3电接触材料。并对所制备的复合材料的导电率、致密度、显微硬度及微观组织进行研究,分析了WC含量对(Cu-Mo)-WC-0.5%La Cl3复合材料组织及性能的影响;利用Gleeble-1500D热-力模拟试验机对复合材料进行等温压缩试验,建立复合材料的本构方程;在UMT-2多功能摩擦磨损试验机上对材料进行摩擦磨损试验,研究WC含量对复合材料摩擦学性能的影响,并用JSM-5610LV扫描电镜观察材料磨损后的表面形貌,初步分析磨损机理;利用JF04C电接触试验机对复合材料的电接触性能进行试验,研究了其在直流阻性负载条件下的材料转移量及转移方向,并用扫描电镜观察材料在电弧侵蚀后的表面形貌,进一步分析材料的电弧侵蚀机理。结果表明:(1)制备出的六种复合材料组织均比较致密,致密度为87.8?94.0%,WC颗粒均匀分散在铜基体上,起到弥散强化作用。其导电率为26.1~31.6%IACS,显微硬度为95~128HV。(2)Cu-Mo-WC复合材料高温流变应力-应变曲线具有典型的动态再结晶特征,其峰值应力随着变形温度的降低或应变速率的升高而增加;计算出了热变形激活能,并建立了复合材料的高温变形本构方程。(3)在相同的工作条件下:随着WC含量的增加复合材料的磨损率有下降的趋势,摩擦系数有稍微的增加;在该试验条件下,材料的磨损机理是磨粒磨损。(4)在20A时材料不发生明显转移,阴极和阳极材料均发生一定损耗;当电流大于20A时,材料从阴极转向阳极,并且转移量随电流的增大而不断增加;电弧侵蚀后触头表面呈现气孔、熔池和凹坑等形貌特征,且电流值越大,其形貌特征越明显;接触电阻随电流的增大而减小;接触电阻和熔焊力随电流变化无明显波动。
[Abstract]:Cu-Mo-WC composites can provide good current conduction due to copper, high melting point molybdenum can resist hot melt welding, and the addition of carbide particles makes the material retain the excellent electrical conductivity and thermal conductivity of copper matrix at the same time. It also increases the strength and high temperature stability of the materials and becomes a new type of electrical contact materials studied at home and abroad in recent years. In this paper, (Cu-Mo) -WC-0.5L _ 3 electrical contact materials with different WC content were prepared by SPS spark plasma sintering. The effect of WC content on the microstructure and properties of (Cu-Mo) -WC-0.5La Cl3 composite was studied. The constitutive equation of composites was established by isothermal compression test with Gleeble-1500D thermal force simulator, and the friction and wear tests were carried out on UMT-2 multifunctional friction and wear tester. The effect of WC content on the tribological properties of the composites was studied. The surface morphology of the composites after wear was observed by JSM-5610LV scanning electron microscope, and the wear mechanism was preliminarily analyzed, and the electrical contact properties of the composites were tested by JF04C electric contact tester. The amount and direction of material transfer under DC resistance load were studied. The surface morphology of the material after arc erosion was observed by scanning electron microscope (SEM), and the mechanism of arc erosion was further analyzed. The results showed that: (1) the microstructure of the six composites was dense, and the density of WC particles was 87.8% and 94.0%, which dispersed uniformly on the copper matrix and played the role of dispersion and strengthening. The conductivity of the composite is 26.1 / 31.6 / IACSs, and the microhardness is 950.128HV. (2) the high temperature rheological stress-strain curves of Cu-Mo-WC composites have typical dynamic recrystallization characteristics, and the peak stress increases with the decrease of deformation temperature or the increase of strain rate, and the activation energy of hot deformation is calculated. The constitutive equation of high temperature deformation of composites was established. (3) under the same working conditions, the wear rate of composites decreased with the increase of WC content, and the friction coefficient increased slightly. The wear mechanism of the material is abrasive wear. (4) at 20A, the material does not transfer obviously, the cathode and anode material lose, when the current is larger than 20A, the material changes from cathode to anode, and the amount of transfer increases with the increase of current. After arc erosion, the contact surface shows the characteristics of porosity, weld pool and pit, and the larger the current value, the more obvious the morphology, the smaller the contact resistance is with the increase of current, and the less the contact resistance and welding force fluctuate with the change of current.
【学位授予单位】：河南科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM501.3;TB33

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