本文選題：Al-Mg-Si-Cu合金 + 析出相�。� 參考：《湖南大學》2015年碩士論文

【摘要】：鋁合金是工業(yè)中應用最廣泛的有色金屬結(jié)構材料,其比強度高,成型性優(yōu)良,也具有良好的耐腐蝕性能,因此在汽車、航空和高鐵等領域得到了廣泛應用。眾所周知,純鋁是一種優(yōu)良的導體,鋁的導電性能在常用金屬材料中排名第四,但由于純鋁機械強度偏低,使其在電力工程等方面的應用受到限制。當合金化后,材料強度獲得一定提升,然而合金化卻會使鋁的導電性能下降。雖然鋁合金作為導電材料已經(jīng)有所應用,但為了使鋁合金作為導電材料或者導熱材料在實際工業(yè)中得到更為廣泛的應用,制造高強高導鋁合金成為電力工業(yè)以及科學界較為關心的問題。在純鋁中添加少量鎂、硅和銅所形成的6xxx系(Al-Mg-Si-Cu)鋁合金是人類現(xiàn)代生活中應用最廣泛的鋁合金。由于鎂、硅和銅三種元素添加對鋁導電性能的影響較小,并且6xxx系鋁合金中合金含量較低,這些綜合因素使6xxx系(Al-Mg-Si-Cu)鋁合金成為合適的輕量化導電導熱材料,尤其是對強度和導電性能提出更高要求時。本課題以形變時效工藝為主線,通過調(diào)控形變前合金元素聚集狀態(tài)以及后續(xù)時效工藝,制備新型高強高導Al-Mg-Si-Cu合金。實驗選取了2種Al-Mg-Si-Cu合金(合金元素總含量相似,Mg/Si比分別是1和2),兩種合金都分別采用傳統(tǒng)T6時效工藝和形變時效工藝處理,然后在不同溫度(150o C、180o C、210o C和240o C)下進行時效處理。本文主要借助硬度測試、導電率測試和拉伸測試以及透射電子顯微鏡(TEM)研究不同工藝制備的Al-Mg-Si-Cu合金的性能和微觀結(jié)構,試圖揭示形變時效工藝對Al-Mg-Si-Cu合金綜合性能(強度和導電率的結(jié)合)改善的機理以及形變量和預處理對Al-Mg-Si-Cu合金綜合性能的影響,建立宏觀性能與微觀結(jié)構特征的關系。本文得到的主要結(jié)論如下:(1)通過改變傳統(tǒng)時效工藝加工順序,對Al-Mg-Si-Cu合金進行形變時效工藝處理,合金綜合性能都獲得較大提升。其原因是形變時效工藝通過在后續(xù)退火前的形變引入大量位錯,位錯在后續(xù)退火后彌補由于析出相過于粗化而下降的強度,使得強度得以保持。位錯本身對材料的導電率幾乎沒有影響,卻可以使析出相顯著粗化,從而合金導電率大幅度提升;(2)選擇合適的后續(xù)時效溫度可以優(yōu)化合金的綜合性能,利用人工時效溫度可以調(diào)控析出相粗化速率以及位錯退化速率,使兩者恰當結(jié)合可以使綜合性能最優(yōu);(3)在形變時效工藝中,由于自然時效和人工時效預處理在基體內(nèi)預制的溶質(zhì)團聚物不同,使得形變過程中引入的位錯含量以及位錯存在的形式有所不同,因而帶來的強化效果不同。后續(xù)時效時,在強度接近的情況下,導電率提高程度不同,最終使得綜合性能有差別;(4)形變時效工藝中形變量不斷增大時,合金綜合性能逐漸提高。形變量增加會使基體內(nèi)預制的位錯量以及位錯存在的形式不同,從而使得合金綜合性能得到不同程度改善。位錯的存在不僅為材料提供強化作用,在后續(xù)時效過程中,位錯也可以作為原子擴散通道,使后續(xù)時效時析出規(guī)律發(fā)生改變。
[Abstract]:Aluminum alloy is the most widely used nonferrous metal structure material in industry. It has high specific strength, good formability and good corrosion resistance. Therefore, it has been widely used in the fields of automobile, aviation and high iron. It is known that pure aluminum is a good conductor. The conductivity of aluminum is fourth in common metal materials. The mechanical strength of pure aluminum is low and its application in power engineering is limited. When alloying, the strength of the material is improved, but alloying will reduce the conductivity of aluminum. Although aluminum alloy has been applied as conductive material, the aluminum alloy is used as conductive material or heat conduction material in actual work. The manufacture of high strength and high conductivity aluminum alloy has become a concern in the power industry and the scientific community. Adding a small amount of magnesium to pure aluminum, 6xxx (Al-Mg-Si-Cu) aluminum alloy formed by silicon and copper is the most widely used aluminum alloy in human modern life. The addition of three elements of magnesium, silicon and copper to aluminum conductance is added to the aluminum alloy. The effect of energy is smaller and the alloy content in 6XXX Al alloy is low. These comprehensive factors make 6xxx (Al-Mg-Si-Cu) aluminum alloy a suitable lightweight conductive and conductive material, especially for the higher requirements of strength and conductivity. The new high strength and high conductivity Al-Mg-Si-Cu alloy was prepared by the subsequent aging process. 2 kinds of Al-Mg-Si-Cu alloys were selected (the total content of the alloy elements was similar, the Mg/Si ratio was 1 and 2 respectively). The two alloys were treated with the traditional T6 aging process and the deformation aging process respectively, and then the aging place was carried out at different temperatures (150O C, 180o C, 210o C and 240o C). In this paper, the properties and microstructure of Al-Mg-Si-Cu alloys prepared by different processes are studied by means of hardness testing, conductivity testing and tensile testing, and transmission electron microscopy (TEM). The mechanism of deformation aging process to improve the comprehensive properties of Al-Mg-Si-Cu alloys (the combination of strength and conductivity), as well as the shape variables and pretreatments are revealed. The relationship between the macroscopic properties and the microstructure characteristics of the Al-Mg-Si-Cu alloy was established. The main conclusions obtained in this paper are as follows: (1) by changing the processing order of the traditional aging process and treating the Al-Mg-Si-Cu alloy by deformable aging process, the comprehensive properties of the alloys have been greatly improved. The reason is that the deformation aging process passes through the process. A large number of dislocation is introduced before the subsequent annealing, and the dislocation is made up to make up the strength of the precipitated phase after the subsequent annealing, which makes the strength keep. The dislocation itself has almost no effect on the conductivity of the material, but can make the precipitated phase coarsely coarsened and the alloy conductivity increased greatly; (2) select the appropriate follow-up time. The effective temperature can optimize the comprehensive properties of the alloy. Using the artificial aging temperature can regulate the precipitate coarsening rate and the dislocation degradation rate, so that the proper combination of the two can make the comprehensive performance optimal. (3) in the deformation aging process, the deformation of the prefabricated solute aggregate in the matrix is different because of the natural aging and artificial aging pretreatment. The content of dislocation and the form of dislocation are different in the process, and the strengthening effect is different. In the case of subsequent aging, the increase of electrical conductivity is different, and the overall performance is different. (4) the comprehensive properties of the alloy gradually increase when the deformation amount is increasing. The increase in the amount of dislocation and dislocation in the matrix makes the overall performance of the alloy improve in varying degrees. The existence of dislocation not only provides a strengthening effect for the material, but the dislocation can also be used as an atomic diffusion channel during the subsequent aging process, which makes the precipitation rule change during the subsequent aging.
【學位授予單位】：湖南大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TG146.21;TG156.92

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本文編號：1997085