本文關(guān)鍵詞： 鋁硅合金 力學(xué)性能 組織 稀土元素　出處：《中北大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：鑄造鋁硅合金具有比強(qiáng)度較高、質(zhì)輕、耐腐蝕等良好的性能,被廣泛的用于汽車、航空航天等領(lǐng)域,其中鋁硅合金主要應(yīng)用于制造發(fā)動機(jī)缸體、缸蓋等鑄件。隨著汽車工業(yè)對產(chǎn)品輕量化和高強(qiáng)韌化的要求不斷提高,提高鋁硅合金的力學(xué)性能就成為迫切需要解決的問題。本文從材料的強(qiáng)韌化出發(fā),以高純鋁為主加原材料,以AlSi7Cu2Mg鋁合金(Si:6%-8%,Cu1.2%-1.8%,Mg0.2%-0.5%,Mn0.1%-0.2%)為基礎(chǔ),分別采用單項(xiàng)實(shí)驗(yàn)和正交試驗(yàn)的方法,優(yōu)化合金元素的配比為(Si7%,Cu1.5%,Mg0.5%,Mn0.1%)。同時還對合金的熔煉工藝進(jìn)行了研究,最終確定出細(xì)化劑Ti的加入量為0.15%,變質(zhì)劑Sr元素加入量為0.06%時AlSi7Cu2Mg的細(xì)化和變質(zhì)能夠達(dá)到最佳效果。隨后,本文系統(tǒng)地研究了不同熱處理工藝對AlSi7Cu2Mg鋁合金的力學(xué)性能和組織的影響,最終確定,最佳處理工藝為490℃×8h+540℃×8.5h+170℃×9.5 h,處理后合金的最高抗拉強(qiáng)度達(dá)到397 MPa,延伸率達(dá)到5.5%。本文還研究了不同含量的稀土元素Y和La對合金鑄態(tài)組織與性能的影響結(jié)果表明:當(dāng)Y含量為0.15%時,AlSi7Cu2Mg合金能夠達(dá)到最好的力學(xué)性能,此時抗拉強(qiáng)度為238MPa,延伸率為4.5%,合金經(jīng)T6熱處理后在250℃的實(shí)驗(yàn)溫度數(shù)值下抗拉強(qiáng)度達(dá)到了273MPa,延伸率為6.9%;含La的AlSi7Cu2Mg在La含量為0.3%時,鑄態(tài)力學(xué)性能最好,抗拉強(qiáng)度為264MPa,經(jīng)過熱處理后合金的抗拉強(qiáng)度達(dá)到417MPa,此時的延伸率為5.9%。
[Abstract]:Cast Al-Si alloy has high specific strength, light weight, corrosion resistance and other good properties. It is widely used in automotive, aerospace and other fields, among which Al-Si alloy is mainly used in manufacturing engine cylinder block. Cylinder head and other castings. With the increasing demand of automobile industry for lightweight and high strength and toughness, improving the mechanical properties of Al-Si alloy has become an urgent problem to be solved. Based on high purity aluminum and AlSi7Cu2Mg aluminum alloy SiW 6-8 and Cu1.2and -1.8mg 0.2and -0.5m _ 0.2and -0.2um), the ratio of alloy elements is optimized by single experiment and orthogonal test, respectively. The melting process of the alloy is also studied. Finally, it is determined that the addition of Ti refiner is 0.15 and the addition of modifier Sr is 0.06. The refinement and modification of AlSi7Cu2Mg can achieve the best results when the addition amount of modifier Sr is 0.06. In this paper, the effects of different heat treatment processes on the mechanical properties and microstructure of AlSi7Cu2Mg aluminum alloy were systematically studied. The optimum treatment process is 490 鈩，

本文編號：1548119