本文選題：7000系軋制材鋁合金 + 淬透性��； 參考：《江蘇大學(xué)》2017年碩士論文

【摘要】：超高強鋁合金一直是航空業(yè)研究的重點材料,隨著大型化飛機的迅速發(fā)展,鋁合金已經(jīng)成為飛機上許多關(guān)鍵零部件的重要材料。然而鋁合金的強度和淬透性成為限制其發(fā)展的關(guān)鍵因素,如何調(diào)控好合金元素的配比是熔煉出綜合性能良好的超高強鋁合金的關(guān)鍵步驟。本文自行設(shè)計熔煉了9種7000系超高強軋制材鋁合金,研究了影響7000系鋁合金淬透性的因素。研究了主合金元素Zn、Mg及微量元素Mn的變化對7000系軋制鋁合金組織與性能的影響。通過對合金進行金相觀察、XRD與EBSD分析研究了其微觀組織,通過硬度、電導(dǎo)率、拉伸性能等測試及晶間與剝落腐蝕試驗研究了其力學(xué)性能和抗腐蝕性能。本文主要研究工作所取得的結(jié)論如下:(1)通過研究了8種不同7000系鋁合金的淬透性規(guī)律,使用SEM進行微觀組織分析,發(fā)現(xiàn)淬透性較差的合金在其遠離淬火端會出現(xiàn)含Zr量高的絮狀析出物,發(fā)現(xiàn)Zr元素是降低合金淬透性的原因。通過分析不同合金的主合金元素原子半徑差總和、微量元素Zr和Mn、雜質(zhì)元素Fe和Si。結(jié)果發(fā)現(xiàn):原子半徑差總和越小,合金的淬透性越好;微量元素Zr和Mn都降低合金的淬透性,而且Mn的影響程度比Zr大;雜質(zhì)元素Fe和Si也會降低合金的淬透性。且當主合金元素原子半徑差總和較小,合金中雜質(zhì)元素含量(Fe和Si)也較低時,可以容納較高含量的Zr元素而保持較高的淬透性;當Zr和雜質(zhì)元素Fe、Si含量較低時,即使原子半徑差總和比較大,也能保持較高的淬透性。(2)研究了Mn元素對7000系軋制材鋁合金Al-9.94Zn-2.35Mg-2.53Cu-xMn-0.25Zr組織與性能的影響。結(jié)果表明:在Zr含量為0.25%時,添加0.41%的Mn元素能夠明顯抑制再結(jié)晶和晶粒長大,并在后續(xù)的固溶時效過程中能夠較好的保留位錯和小角度晶界,對合金有一定的強化效果。添加Mn元素后,合金在T6時效下強度比不含Mn元素的合金有所提升,從598.5 MPa提升到617.6 MPa,但經(jīng)過T76時效后強度下降明顯,從617.6 MPa降低到566.4 MPa,降低了8.3%,發(fā)現(xiàn)Mn元素能減少合金過時效的時間,不利于合金在T76過時效下強度的發(fā)揮。Mn元素會降低了軋制材鋁合金抗剝落腐蝕性能,能提升抗晶間腐蝕性能。(3)研究了Mg元素及微量Mn元素對超高強軋制材鋁合金Al-9.1Zn-xMg-2.72Cu-xMn-0.26Zr組織與性能的影響。結(jié)果表明:Mg元素具有促進再結(jié)晶的作用,Mg含量提高會導(dǎo)致合金再結(jié)晶程度增高,晶粒長大,晶粒等軸性改善,但再結(jié)晶過程消耗了較多的位錯和低角度晶界,使合金強度有所降低;Mg元素提高會降低合金的抗晶間腐蝕性能,能夠提高軋制材鋁合金抗剝落腐蝕性能。復(fù)合添加0.41 Mn+0.25 Zr能夠抑制再結(jié)晶和晶粒長大,復(fù)合添加0.2 Mn+0.25 Zr不能抑制再結(jié)晶,但可以抑制晶粒長大。開發(fā)了性能優(yōu)異的7000系鋁合金,其合金成分為Al-8.94Zn-2.55Mg-2.63Cu-0.26Zr,在T76時效下強度達到628.9MPa,延伸率為7.3%,抗剝落腐蝕等級達到PB級。(4)研究了Zn元素對超高強軋制材鋁合金Al-xZn-2.62Mg-1.29Cu-2.0Zr組織與性能的影響。結(jié)果表明:Zn元素具有促進再結(jié)晶的作用,Zr元素對再結(jié)晶有抑制作用,當Zn/Mg值超過3.61時,合金中Zn元素提高不能增加合金中時效沉淀強化相,合金的強度反而有所降低,Zn含量越高,合金的抗晶間腐蝕性能越差,對抗剝落腐蝕性能影響不大。本實驗開發(fā)了抗拉強度達到682.2 MPa的超高強鋁合金,其合金成分為Al-9.79Zn-2.71Mg-1.27Cu-0.15Zr,在T6時效下抗拉強度達到682.2 MPa,延伸率為6.2%,T76時效下抗拉強度也達到630.1 MPa,延伸率為7.76%,硬度也分別為226.9 HV和207.8 HV,T76時效下其抗晶間腐蝕性能達到3級,抗剝落腐蝕性能為PC級,單端淬透性也達到80mm,綜合性能優(yōu)異。
[Abstract]:Super high strength aluminum alloy has always been the key material in the research of aviation industry. With the rapid development of large-scale aircraft, aluminum alloy has become an important material for many key parts of the aircraft. However, the strength and hardenability of aluminum alloy have become the key factor to limit its development. How to regulate the ratio of alloy elements is a good melting process. The key step of super high strength aluminum alloy is to melt 9 kinds of 7000 series super high strength rolled aluminum alloy. The factors affecting the hardenability of 7000 series aluminum alloy were studied. The influence of the changes of the main alloy elements Zn, Mg and trace element Mn on the microstructure and properties of the 7000 series aluminum alloy were studied. The alloy was observed by metallographic examination, XRD The microstructures of the microstructures were studied by EBSD analysis. The mechanical properties and corrosion resistance were studied through the tests of hardness, conductivity, tensile properties and intergranular and exfoliation corrosion tests. The main conclusions of this paper are as follows: (1) the hardenability of 8 different 7000 series aluminum alloys was studied, and the microstructure of the alloy was made by SEM. It is found that the alloy with high Zr content will appear at the far away from the quenching end. It is found that the Zr element is the cause of reducing the hardenability of the alloy. By analyzing the sum of the atomic radius difference of the main alloy elements, the trace elements Zr and Mn, the impurity elements Fe and Si., the results of the impurity elements Fe and Si. are found: the smaller the atomic radius difference, the quenching of the alloy. The better permeability is, the microelements Zr and Mn both reduce the hardenability of the alloy, and the effect of Mn is greater than that of Zr; the impurity elements Fe and Si also reduce the hardenability of the alloy. And when the sum of the atomic radius difference of the main alloy elements is smaller and the content of the impurity elements (Fe and Si) in the alloy is also low, it can hold a higher content of the Zr element to maintain a higher quenching. When the content of Zr and impurity elements Fe and Si is low, even if the sum of the atomic radius difference is larger, it can also maintain a higher hardenability. (2) the effect of the Mn element on the microstructure and properties of the aluminum alloy Al-9.94Zn-2.35Mg-2.53Cu-xMn-0.25Zr of the 7000 series rolling material is investigated. The results show that the addition of 0.41% Mn elements can be significantly inhibited when the content of Zr is 0.25%. When the crystallization and grain grow up, the dislocation and small angle grain boundary can be retained in the subsequent solution and aging process. The alloy has a certain strengthening effect on the alloy. After adding Mn element, the strength of the alloy in T6 aging is higher than that of the alloy without Mn element, from 598.5 MPa to 617.6 MPa, but the strength decreases obviously after aging after T76, from 617.. 6 MPa decreased to 566.4 MPa and decreased by 8.3%. It was found that the Mn element could reduce the time of over aging of the alloy, and it was not conducive to the strength of the alloy under T76 over aging. The.Mn element could reduce the corrosion resistance and enhance the intergranular corrosion resistance of the rolled aluminum alloy. (3) the Mg element and the trace Mn element were studied for the ultra-high strength rolled aluminum alloy Al-9.1. The effect of Zn-xMg-2.72Cu-xMn-0.26Zr on the microstructure and properties shows that the Mg element has the effect of promoting recrystallization. The increase of Mg content will lead to the increase of the recrystallization degree of the alloy, the grain growth and the equiaxed grain of the grain, but the recrystallization process consumes more dislocation and low angle crystal boundary, which reduces the strength of the alloy, and the increase of the Mg element will decrease. The anti exfoliation corrosion resistance of the alloy can be improved by the anti crystal corrosion resistance of the alloy. Adding 0.41 Mn+0.25 Zr can inhibit recrystallization and grain growth. Adding 0.2 Mn+0.25 Zr can not inhibit recrystallization, but the grain growth can be inhibited. A 7000 series aluminum alloy with excellent performance is developed, and its alloy composition is Al-8.94Zn-2.55Mg- 2.63Cu-0.26Zr, the strength of T76 is 628.9MPa, the elongation is 7.3%, the anti peeling corrosion grade reaches PB grade. (4) the effect of Zn element on the microstructure and properties of ultra-high strength rolled aluminum alloy Al-xZn-2.62Mg-1.29Cu-2.0Zr is studied. The results show that the Zn element has the effect of promoting recrystallization, Zr elements have inhibition effect on recrystallization, when Zn/Mg When the value is more than 3.61, the increase of Zn element in the alloy can not increase the aging precipitation strengthening phase in the alloy, but the strength of the alloy decreases. The higher the Zn content, the worse the intercrystalline corrosion resistance of the alloy, the less influence on the exfoliation corrosion resistance. This experiment developed a super high strength aluminum alloy with a tensile strength of 682.2 MPa, and its alloy composition is Al-9.79Z N-2.71Mg-1.27Cu-0.15Zr, the tensile strength of the T6 is 682.2 MPa, the elongation is 6.2%, the tensile strength of the T76 is 630.1 MPa, the elongation is 7.76%, the hardness is 226.9 HV and 207.8 HV respectively. The anti crystal corrosion resistance of T76 is 3, the anti peeling corrosion resistance is PC, the single end quenching is also 80mm, and the comprehensive properties are also achieved. Excellent.
【學(xué)位授予單位】：江蘇大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TG146.21;TG339

【參考文獻】

相關(guān)期刊論文 前10條

1 李巖;趙業(yè)青;陳修梵;魯法云;張玲艷;張麗芝;;鋁合金鍛造生產(chǎn)技術(shù)的發(fā)展[J];輕合金加工技術(shù);2015年08期

2 莫紀平;程曉農(nóng);鄧平安;許曉靜;吳瑤;蔣偉;;多向壓縮對7085鋁合金擠壓材組織和力學(xué)性能的影響[J];稀有金屬材料與工程;2015年08期

3 張新明;張端正;劉勝膽;李承波;鄧運來;;基于末端淬火試驗研究3種7000系鋁合金的淬透性[J];中南大學(xué)學(xué)報(自然科學(xué)版);2015年02期

4 夏濤;陳子勇;聶祚仁;;高鋅超高強鋁合金微觀組織及力學(xué)性能研究[J];熱加工工藝;2015年02期

5 廖郁國;韓曉祺;曾苗霞;金曼;;Cu元素對7XXX系列鋁合金再結(jié)晶的影響[J];上海金屬;2014年03期

6 李承波;張新明;劉勝膽;吳澤政;鄧運來;;7085鋁合金剝落腐蝕的淬火敏感性[J];材料研究學(xué)報;2013年05期

7 李春紅;李春梅;;熱處理對5083鋁合金晶間腐蝕與力學(xué)性能的影響[J];功能材料;2013年S1期

8 劉勝膽;李承波;歐陽惠;鄧運來;張新明;劉星興;;超高強7000系鋁合金的淬火敏感性[J];中國有色金屬學(xué)報;2013年04期

9 王雷;黃汝剛;袁文生;;鋁合金軋制成形的研究與現(xiàn)狀[J];鍛壓裝備與制造技術(shù);2012年05期

10 叢福官;趙剛;田妮;韓嘯;朱銘熙;于金浩;;7×××系超高強鋁合金的強韌化研究進展及發(fā)展趨勢[J];輕合金加工技術(shù);2012年10期

相關(guān)博士學(xué)位論文 前1條

1 李海;Ag、Sc合金化及熱處理工藝對7055鋁合金的微觀組織與性能影響研究[D];中南大學(xué);2005年

相關(guān)碩士學(xué)位論文 前5條

1 談成;初始形變儲能、升溫速率和固溶時間對7085鋁合金組織與性能的影響[D];江蘇大學(xué);2016年

2 Emilie Le Gal;雜質(zhì)含量對7055鋁合金微觀組織與應(yīng)力腐蝕性能的影響[D];上海交通大學(xué);2015年

3 董朋軒;Al-8.54Zn-2.41Mg-xCu超強鋁合金多相組織調(diào)控及性能研究[D];中南大學(xué);2013年

4 陳慧;Al-Zn-Mg-Cu合金的淬火敏感性及時效析出行為研究[D];中南大學(xué);2012年

5 熊明華;Al-Zn-Mg-Cu合金形變熱處理工藝的研究[D];湖南大學(xué);2012年

，

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