本文選題：鋁合金 + 鉆桿��； 參考：《吉林大學》2015年碩士論文

【摘要】：鋁合金鉆桿具有低密度、高比強度、無磁性以及良好的耐低溫性能，在石油鉆探、海洋鉆探、極地鉆探以及大陸深部科學鉆探中越來越發(fā)揮著重要作用，，有著非常廣泛的應用前景�？蔁崽幚韽娀母邚姸蠕X合金7075和2024是制備鋁合金鉆桿的典型材料。因其具有良好的力學性能，已經(jīng)在大陸科學鉆探和極地科學鉆探等領域得到部分應用。但是，由于鋁合金對含有氯離子(Cl-)的環(huán)境具有較強的腐蝕敏感性，鋁合金鉆桿在海洋鉆探、含鹽地層和含鹽鉆井液的環(huán)境使用過程中，不可避免地會面臨由Cl-所致的腐蝕問題。因此，研究和評價7075和2024鋁合金鉆桿在Cl-環(huán)境下的腐蝕性能就顯得尤為重要。本文亦對一種試研的、具有高強度高耐磨性的原位析出TiB2粒子的7075復合材料進行了腐蝕性能研究。采用動電位極化試驗，定量研究、分析了三種材料的腐蝕敏感性和腐蝕速率；應用掃描電鏡(SEM)，能譜分析(EDS)和電子背散射衍射(EBSD)技術研究鋁合金材料的腐蝕機制，分析了合金成分、相組成、晶界特征分布（GBCD）和晶粒變形能等因素對腐蝕的影響。 研究表明，2024鋁合金鉆桿的耐腐蝕性高于7075鋁合金鉆桿，且隨著擠壓比的不同，鉆桿不同部位的腐蝕性能有很大差異。從腐蝕機制來看，7075鋁合金鉆桿的腐蝕形式包括點蝕、晶間腐蝕和剝蝕；而2024鋁合金只有點蝕和晶間腐蝕兩種腐蝕形式。兩種材料的腐蝕性能區(qū)別主要是由于兩者合金成分以及熱處理方式不同造成的。 7075-TiB2鋁基復合材料的腐蝕率與TiB2顆粒的比例呈現(xiàn)對應關系。該復合材料的腐蝕行為主要與由原位TiB2顆粒引起的位錯密度的變化有關。該種鋁基復合材料在腐蝕過程中主要表現(xiàn)出點蝕和晶間腐蝕兩種腐蝕形式；而且點蝕發(fā)生于晶內。7075-TiB2鋁基復合材料的選擇性點蝕具有晶粒間非對稱的特點，主要歸因于由TiB2顆粒與鋁基體的熱膨脹系數(shù)錯配所致的局部位錯密度不同。組織中的富Cu的金屬間化合物與鋁基體間的界面腐蝕緣于成分不均所致的電化學反應。其脫落導致微點蝕的發(fā)生。 鋁合金及鋁基復合材料的晶間腐蝕的選擇性特點主要與晶界特征分布(GBCD)有關。大角度晶界易于腐蝕，而特殊晶界和小角度晶界具有耐腐蝕性。
[Abstract]:Aluminum alloy drill pipes with low density, high specific strength, nonmagnetic properties and good low temperature resistance are playing more and more important roles in oil drilling, offshore drilling, polar drilling and deep continental scientific drilling. It has a very wide application prospect. High strength aluminum alloy 7075 and 2024, which can be strengthened by heat treatment, are typical materials for producing aluminum alloy drill pipe. Because of its good mechanical properties, it has been used in some fields such as continental scientific drilling and polar scientific drilling. However, because aluminum alloy has a strong corrosion sensitivity to the environment containing chloride ion, aluminum alloy drill pipe will inevitably face the corrosion problem caused by Cl-in the process of offshore drilling, salt formation and environment use of salt drilling fluid. Therefore, it is very important to study and evaluate the corrosion resistance of 7075 and 2024 aluminum alloy drill pipes under Cl- environment. The corrosion properties of a kind of in-situ precipitated TiB2 particles with high strength and high wear resistance were also investigated in this paper. The corrosion susceptibility and corrosion rate of three kinds of materials were analyzed by potentiodynamic polarization test and quantitative study, and the corrosion mechanism of aluminum alloy was studied by means of SEM, EDS and EBSD. The effects of alloy composition, phase composition, grain boundary characteristic distribution (GBCD) and grain deformation energy on corrosion were analyzed. The results show that the corrosion resistance of 7075 aluminum alloy drill pipe is higher than that of 7075 aluminum alloy drill pipe, and the corrosion resistance of different parts of drill pipe varies greatly with different extrusion ratio. From the corrosion mechanism, the corrosion forms of aluminum alloy drill pipe include pitting corrosion, intergranular corrosion and denudation, while 2024 aluminum alloy has only two corrosion forms: pitting corrosion and intergranular corrosion. The difference of corrosion performance between the two materials is mainly due to the difference of alloy composition and heat treatment. The corrosion rate of 7075-TiB2 aluminum matrix composites is proportional to the proportion of TiB2 particles. The corrosion behavior of the composite is mainly related to the change of dislocation density caused by in situ TiB2 particles. In the process of corrosion, the aluminum matrix composites mainly show pitting corrosion and intergranular corrosion, and the selective pitting corrosion of aluminum matrix composite occurs in the intragranular. 7075-TiB2 aluminum matrix composite has the characteristics of asymmetric grain size. The local dislocation density due to the mismatch of thermal expansion coefficient between TiB2 particles and aluminum matrix is mainly attributed to the difference of local dislocation density. The interfacial corrosion between Cu-rich intermetallic compounds and aluminum matrix is due to the electrochemical reaction caused by uneven composition. Its shedding results in the occurrence of micropitting. The selective characteristics of intergranular corrosion of aluminum alloy and aluminum matrix composites are mainly related to the distribution of grain boundary characteristics (GBCDs). Large angle grain boundary is easy to corrode, and special grain boundary and small angle grain boundary have corrosion resistance.
【學位授予單位】：吉林大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：P634.4

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相關期刊論文 前3條

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本文編號：1800455