本文選題：Cu-Cr電接觸復合材料 + 放電等離子燒結��； 參考：《河南科技大學》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,其性能直接關系到電器運行的可靠性和使用壽命。Cu-Cr復合材料既有Cu優(yōu)良的導電、導熱性以及良好塑性等優(yōu)點又有Cr的高強度、低截流值以及較好的滅弧性等特點,是理想的“結構-功能一體化”復合材料之一。本文利用放電等離子燒結法(簡稱SPS)制備出不同Cr含量的Cu-Cr電接觸復合材料。對所得復合材料進行致密度、硬度和電導率測試,然后觀察其微觀組織;分析Cr對Cu-Cr電接觸復合材料組織與性能的影響;利用Gleeble-1500D熱/力模擬機進行高溫熱壓縮變形試驗,在熱形變溫度650~950℃、應變速率0.001~10 s-1范圍內,分析Cu-Cr電接觸復合材料的流變應力曲線特征,依據雙曲函數(shù)模型求出材料的熱激活能并構建流變應力本構方程,然后對本構方程進行精度檢驗;利用動態(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電接觸測試系統(tǒng)對Cu-Cr復合材料進行恒流負載條件下的電接觸性能測試,分析不同電流強度下材料的損耗和轉移量,結合材料表面電弧侵蝕微觀形貌對其侵蝕機理進行討論。研究結果表明:1.SPS法制備的三種Cu-Cr電接觸復合材料組織均勻致密,增強相Cr顆粒彌散分散在銅基體上,致密度為94.3%~97.7%、導電率為39.0%IACS~59.2%IACS、硬度為63.2~72.4HBW。隨著Cr含量增多,其致密度和電導率逐漸減少,硬度則呈現(xiàn)增大趨勢。2.Cu-Cr電接觸復合材料的流變應力曲線具有動態(tài)回復和動態(tài)再結晶特征,峰值應力會隨應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,并且所構建復合材料的本構方程精度較高。3.依據不同應變條件下的應力值,繪制出材料的熱加工圖,并結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電接觸復合材料損耗加劇,且當電流值增加到30 A時,材料發(fā)生從陰極到陽極的轉移;電流強度增加,轉移量增多。觸頭表面電弧侵蝕會呈現(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間之間具有正相關的線性關系。隨著試驗次數(shù)增加,接觸電阻和熔焊力之間無明顯變化規(guī)律,接觸電阻隨電流的增加逐漸減小,熔焊力有增大趨勢。
[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：1859344