本文選題：電接觸材料 + 放電等離子燒結��； 參考：《河南科技大學》2015年碩士論文

【摘要】：Cu-Mo-WC復合材料由于銅能夠提供良好的電流導通,高熔點鉬能抵抗熱熔焊,加入的碳化物顆粒使得材料在保留了銅基體優(yōu)越的導電性、導熱性能的同時,還增加了材料的強度和耐高溫穩(wěn)定性,成為近些年來國內外研究的新型電接觸材料。本文采用SPS放電等離子燒結工藝制備出不同WC含量的(Cu-Mo)-WC-0.5%LaCl3電接觸材料。并對所制備的復合材料的導電率、致密度、顯微硬度及微觀組織進行研究,分析了WC含量對(Cu-Mo)-WC-0.5%La Cl3復合材料組織及性能的影響;利用Gleeble-1500D熱-力模擬試驗機對復合材料進行等溫壓縮試驗,建立復合材料的本構方程;在UMT-2多功能摩擦磨損試驗機上對材料進行摩擦磨損試驗,研究WC含量對復合材料摩擦學性能的影響,并用JSM-5610LV掃描電鏡觀察材料磨損后的表面形貌,初步分析磨損機理;利用JF04C電接觸試驗機對復合材料的電接觸性能進行試驗,研究了其在直流阻性負載條件下的材料轉移量及轉移方向,并用掃描電鏡觀察材料在電弧侵蝕后的表面形貌,進一步分析材料的電弧侵蝕機理。結果表明:(1)制備出的六種復合材料組織均比較致密,致密度為87.8?94.0%,WC顆粒均勻分散在銅基體上,起到彌散強化作用。其導電率為26.1~31.6%IACS,顯微硬度為95~128HV。(2)Cu-Mo-WC復合材料高溫流變應力-應變曲線具有典型的動態(tài)再結晶特征,其峰值應力隨著變形溫度的降低或應變速率的升高而增加;計算出了熱變形激活能,并建立了復合材料的高溫變形本構方程。(3)在相同的工作條件下:隨著WC含量的增加復合材料的磨損率有下降的趨勢,摩擦系數有稍微的增加;在該試驗條件下,材料的磨損機理是磨粒磨損。(4)在20A時材料不發(fā)生明顯轉移,陰極和陽極材料均發(fā)生一定損耗;當電流大于20A時,材料從陰極轉向陽極,并且轉移量隨電流的增大而不斷增加;電弧侵蝕后觸頭表面呈現氣孔、熔池和凹坑等形貌特征,且電流值越大,其形貌特征越明顯;接觸電阻隨電流的增大而減小;接觸電阻和熔焊力隨電流變化無明顯波動。
[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.
【學位授予單位】：河南科技大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TM501.3;TB33

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