發(fā)布時(shí)間：2018-05-08 01:23

  本文選題：Cu-Cr電接觸復(fù)合材料 + 放電等離子燒結(jié)��； 參考：《河南科技大學(xué)》2017年碩士論文

【摘要】：電觸頭是電器控制過程中的重要組成元件,具有連通或斷開電路電流的作用,其性能直接關(guān)系到電器運(yùn)行的可靠性和使用壽命。Cu-Cr復(fù)合材料既有Cu優(yōu)良的導(dǎo)電、導(dǎo)熱性以及良好塑性等優(yōu)點(diǎn)又有Cr的高強(qiáng)度、低截流值以及較好的滅弧性等特點(diǎn),是理想的“結(jié)構(gòu)-功能一體化”復(fù)合材料之一。本文利用放電等離子燒結(jié)法(簡(jiǎn)稱SPS)制備出不同Cr含量的Cu-Cr電接觸復(fù)合材料。對(duì)所得復(fù)合材料進(jìn)行致密度、硬度和電導(dǎo)率測(cè)試,然后觀察其微觀組織;分析Cr對(duì)Cu-Cr電接觸復(fù)合材料組織與性能的影響;利用Gleeble-1500D熱/力模擬機(jī)進(jìn)行高溫?zé)釅嚎s變形試驗(yàn),在熱形變溫度650~950℃、應(yīng)變速率0.001~10 s-1范圍內(nèi),分析Cu-Cr電接觸復(fù)合材料的流變應(yīng)力曲線特征,依據(jù)雙曲函數(shù)模型求出材料的熱激活能并構(gòu)建流變應(yīng)力本構(gòu)方程,然后對(duì)本構(gòu)方程進(jìn)行精度檢驗(yàn);利用動(dòng)態(tài)材料模型繪制材料的熱加工圖,確定最佳加工范圍;利用JF04C電接觸測(cè)試系統(tǒng)對(duì)Cu-Cr復(fù)合材料進(jìn)行恒流負(fù)載條件下的電接觸性能測(cè)試,分析不同電流強(qiáng)度下材料的損耗和轉(zhuǎn)移量,結(jié)合材料表面電弧侵蝕微觀形貌對(duì)其侵蝕機(jī)理進(jìn)行討論。研究結(jié)果表明:1.SPS法制備的三種Cu-Cr電接觸復(fù)合材料組織均勻致密,增強(qiáng)相Cr顆粒彌散分散在銅基體上,致密度為94.3%~97.7%、導(dǎo)電率為39.0%IACS~59.2%IACS、硬度為63.2~72.4HBW。隨著Cr含量增多,其致密度和電導(dǎo)率逐漸減少,硬度則呈現(xiàn)增大趨勢(shì)。2.Cu-Cr電接觸復(fù)合材料的流變應(yīng)力曲線具有動(dòng)態(tài)回復(fù)和動(dòng)態(tài)再結(jié)晶特征,峰值應(yīng)力會(huì)隨應(yīng)變速率的增加和溫度的下降而升高;得出Cu-10Cr、Cu-20Cr和Cu-30Cr三種復(fù)合材料熱變形激活能為:260.743 kJ/mol、242.336 kJ/mol和246.365 kJ/mol,并且所構(gòu)建復(fù)合材料的本構(gòu)方程精度較高。3.依據(jù)不同應(yīng)變條件下的應(yīng)力值,繪制出材料的熱加工圖,并結(jié)合其熱變形微觀組織分析材料的熱變形特征,確定最佳工藝參數(shù)。4.隨著電流值增大,Cu-Cr電接觸復(fù)合材料損耗加劇,且當(dāng)電流值增加到30 A時(shí),材料發(fā)生從陰極到陽(yáng)極的轉(zhuǎn)移;電流強(qiáng)度增加,轉(zhuǎn)移量增多。觸頭表面電弧侵蝕會(huì)呈現(xiàn)有氣孔、裂縫、凹坑、熔池等多種形貌特征。材料的燃弧能量與燃弧時(shí)間之間具有正相關(guān)的線性關(guān)系。隨著試驗(yàn)次數(shù)增加,接觸電阻和熔焊力之間無(wú)明顯變化規(guī)律,接觸電阻隨電流的增加逐漸減小,熔焊力有增大趨勢(shì)。
[Abstract]:Electrical contact is an important component of electrical apparatus control process. It has the function of connecting or disconnecting circuit current. Its performance is directly related to the reliability and service life of electrical apparatus. Cu-Cr composite has excellent electrical conductivity of Cu. The advantages of thermal conductivity and good plasticity have the advantages of high strength of Cr, low cut-off value and good arc extinguishing property. It is one of the ideal "structure-function integration" composite materials. In this paper, Cu-Cr electrical contact composites with different Cr content were prepared by spark plasma sintering (SPS). The density, hardness and conductivity of the composites were measured, and then the microstructure of the composites was observed. The effect of Cr on the microstructure and properties of the Cu-Cr composites was analyzed. The thermal compression deformation tests at high temperature were carried out by using the Gleeble-1500D thermal / mechanical simulator. In the temperature range of 650 ~ 950 鈩，

本文編號(hào)：1859344