發(fā)布時(shí)間：2018-04-20 05:37

  本文選題：AZ91D鎂合金 + 微弧氧化��； 參考：《長(zhǎng)安大學(xué)》2015年碩士論文

【摘要】：鎂合金具有優(yōu)良的力學(xué)性能和切削加工性能,但其活潑的化學(xué)性能卻阻礙了其應(yīng)用范圍的進(jìn)一步擴(kuò)大,經(jīng)表面處理后的鎂合金可有效改善耐蝕性、耐磨性以及耐熱性能。微弧氧化技術(shù)作為表面處理技術(shù)中最具前途的技術(shù)之一,具有工藝簡(jiǎn)單,生成膜層性能優(yōu)良等特點(diǎn)。本文在AZ91D鎂合金表面在鋯鹽溶液中通過(guò)微弧氧化技術(shù),在不同電參數(shù)下制備了不同厚度的微弧氧化膜層,利用SEM、EDS、XRD等分析了膜層的微觀形貌及物相組成,通過(guò)高溫氧化試驗(yàn)和抗熱震性試驗(yàn)對(duì)比了不同處理電壓下獲得的膜層的熱穩(wěn)定性,討論了處理電壓對(duì)膜層高溫氧化行為和抗熱震性的影響,研究結(jié)果表明:處理電壓200V條件下獲得厚度為10μm的均勻膜層,處理電壓300V條件下獲得厚度為17μm的均勻膜層,處理電壓下400V條件下獲得厚度為37μm的均勻膜層,隨著膜層厚度的增加,膜層中疏松層與致密層厚度比例增加;在300℃和400℃條件下加熱至128h后,膜層厚度在40μm內(nèi)的AZ91D鎂合金微弧氧化試樣,隨著膜層厚度的增加,膜層中致密層和疏松層厚度的增加使膜層對(duì)氧的阻擋作用增強(qiáng),膜層中的氧化增重量降低,膜層中能夠承載的氧化物極限值升高,膜層破壞程度減輕,膜層在高溫下保持完整的時(shí)間增加,高溫氧化產(chǎn)物主要由鎂和氧組成;在400℃條件下進(jìn)行50次熱震試驗(yàn)后,觀察試樣表面微觀形貌可知,試樣表面出現(xiàn)明顯裂紋的先后順序?yàn)?00V試樣、300V試樣和400V試樣,且隨著處理電壓的升高,試樣表面的裂紋數(shù)量減少,膜層破壞程度降低;隨處理電壓的升高,膜層中疏松層厚度的比例增加,膜層整體的韌性增強(qiáng),能夠承受的熱震次數(shù)增加,抗熱震性得到提升。
[Abstract]:Magnesium alloys have excellent mechanical properties and cutting and processing properties, but their active chemical properties hinder the further expansion of their application scope. The surface treated magnesium alloys can effectively improve the corrosion resistance, wear resistance and heat resistance. As one of the most promising surface treatment technologies, micro-arc oxidation technology has the advantages of simple process and excellent properties of film formation. In this paper, microarc oxide films with different thickness were prepared on the surface of AZ91D magnesium alloys by micro-arc oxidation in zirconium salt solution under different electrical parameters. Through high temperature oxidation test and thermal shock resistance test, the thermal stability of the film obtained under different treatment voltage was compared, and the effect of treatment voltage on the high temperature oxidation behavior and thermal shock resistance of the film was discussed. The results show that a uniform film with a thickness of 10 渭 m is obtained at the treatment voltage of 200V, a uniform film with a thickness of 17 渭 m is obtained at the treatment voltage of 300V, and a uniform film with a thickness of 37 渭 m is obtained under the treatment voltage of 400V. With the increase of film thickness, the ratio of loose layer to dense layer increases, and when heated to 128 h at 300 鈩，

本文編號(hào)：1776483