本文選題：過共晶Al-20Si合金 + 初晶硅　； 參考：《沈陽理工大學(xué)》2017年碩士論文

【摘要】：過共晶鋁硅合金與普通鋼鐵材料相比具有密度小、比強(qiáng)度高、熱膨脹系數(shù)低、耐磨損等優(yōu)點(diǎn),被廣泛用于航空航天、汽車、高速列車、建筑、電子產(chǎn)品等領(lǐng)域。但是隨著硅含量的增加,過共晶鋁硅合金中存在的形貌粗大初晶硅,長(zhǎng)針狀共晶硅,嚴(yán)重的割裂了基體,降低了過共晶鋁硅合金的機(jī)械性能。因此,開展增強(qiáng)過共晶鋁硅合金機(jī)械性能研究極具意義。論文研究的主要內(nèi)容和結(jié)論如下:本課題主要研究在過共晶Al-20Si合金中添加金屬元素Mg、Ti、Mn、Cu、Ni、Bi,細(xì)化變質(zhì)劑Al-P、稀土元素Ce和La后的過共晶多元Al-20Si合金,通過改變Ni、Bi兩種金屬元素在合金中的含量,并將合金經(jīng)過T6熱處理,研究合金中組織形貌的變化對(duì)合金機(jī)械性能的影響。利用AFT-DC130光學(xué)顯微鏡,觀察過共晶多元Al-20Si合金的金相組織。實(shí)驗(yàn)結(jié)果證明Bi元素對(duì)經(jīng)過變質(zhì)處理后合金中的初晶硅影響不大,但能夠使合金中的共晶硅發(fā)生球化現(xiàn)象。Ni元素不僅可以使共晶硅細(xì)化,還能夠與多元合金中的其他金屬元素結(jié)合形成網(wǎng)狀、長(zhǎng)條狀等不規(guī)則形狀,經(jīng)過XRD分析可知為A13Ni、A17Cu4Ni等富Ni相金屬化合物。利用HVS-5維氏顯微硬度計(jì),測(cè)試過共晶多元Al-20Si合金的硬度。結(jié)果表明隨著Bi含量的增加,合金的硬度呈逐漸減小的趨勢(shì);而隨著Ni含量的增加,合金的硬度呈現(xiàn)逐漸增加的趨勢(shì)。利用YDX-Ⅲ9702壓電式測(cè)力儀測(cè)量軸向切深ap分別為0.4～0.8mm,進(jìn)給量f為100～300mm/min,主軸轉(zhuǎn)速n為470～650r/min條件下合金的切削力。結(jié)果證明合金的切削力隨著Ni含量的增加呈現(xiàn)先增加后減小得趨勢(shì),合金的表面粗糙度則隨著Ni含量的增加而降低。通過對(duì)Ni含量為0.8%和1.2%的兩組實(shí)驗(yàn)合金的切削力進(jìn)行計(jì)算,得出合金切削力通用公式中的系數(shù)。Ni含量為0.8%和1.2%的兩組實(shí)驗(yàn)合金切削力通用公式如下:Ni 含量為 0.8%: F=9.8. ..B.Z (單位/N)Ni 含量為 1.2% : F=9.8 . . . B . Z (單位/N)利用MMW— 1A組態(tài)控制萬能摩擦磨損試驗(yàn)機(jī),在試驗(yàn)力45N,轉(zhuǎn)速300 r/min,持續(xù)時(shí)間為10 min條件下進(jìn)行干摩擦磨損實(shí)驗(yàn),然后用BS124S型天平稱量合金失重。結(jié)果表明,由于Bi元素具有自潤(rùn)滑作用,隨著Bi的質(zhì)量百分?jǐn)?shù)從0.0%增加到1.5%后,合金的摩擦系數(shù)從0.74下降到0.58,磨損量從2.8mg減小到2.3mg。隨著Ni的百分含量從0.4%增加到1.2%后,合金的硬度增加,合金的摩擦系數(shù)從0.74下降到0.52,磨損量從2.8mg減小到2.1mg,磨損機(jī)制由黏著磨損轉(zhuǎn)變?yōu)檩p微的磨粒磨損和疲勞磨損,合金的耐磨性能提高。
[Abstract]:Hypereutectic Al-Si alloy has the advantages of low density, high specific strength, low coefficient of thermal expansion, wear resistance and so on. It is widely used in aerospace, automobile, high-speed train, building, electronic products and other fields. However, with the increase of silicon content, the morphology of primary silicon and long needle eutectic silicon in hypereutectic aluminum-silicon alloy are coarse, which seriously split the matrix and reduce the mechanical properties of hypereutectic Al-Si alloy. Therefore, it is of great significance to study the mechanical properties of hypereutectic Al-Si alloys. The main contents and conclusions of this paper are as follows: in this paper, the hypereutectic multicomponent Al-20Si alloy after the addition of the metal element MgTI-TiMnMn-Cu-NiBi, the refined modifier Al-P, the rare earth element ce and La was studied. The effect of microstructure and morphology on the mechanical properties of the alloy was studied by changing the content of the two kinds of metal elements in the alloy and heat treatment of the alloy with T6. The microstructure of eutectic multicomponent Al-20Si alloy was observed by AFT-DC130 optical microscope. The experimental results show that Bi element has little effect on the primary silicon in the alloy after modification, but it can make the eutectic silicon spheroidized in the alloy. The Ni element can not only refine the eutectic silicon. It can also be combined with other metal elements in the multicomponent alloy to form irregular shape such as network and long strip. By XRD analysis, it can be known as Ni rich metal compounds, such as A13NiGN, A17Cu4Ni and so on. The hardness of hypereutectic multicomponent Al-20Si alloy was measured by HVS-5 Vickers microhardness meter. The results show that the hardness of the alloy decreases with the increase of Bi content and increases with the increase of Ni content. YDX- 鈪，

本文編號(hào)：2095324