利用薄片穿透法确定铝合金最大蚀坑深度
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摘要
目的研究铝合金最大蚀坑深度与环境试验时间的对应关系,为新型合金服役前的耐蚀性评级和结构件服役过程中的剩余寿命预测提供技术基础。方法利用光学显微镜、扫描电镜分析海洋大气环境中新型铝合金的腐蚀类型,并利用薄片穿透法研究铝合金薄片最大蚀坑深度与试验时间的对应关系。结果经过海洋大气环境暴露试验后,2A97铝合金发生了深入合金内部的严重点蚀,检测薄片试样背面电解液的出现时间,可以确定环境试验中蚀坑穿透薄片试样的时间。通过测量不同厚度薄片试样的穿透时间,可以确定最快生长局部腐蚀点的深度和时间的关系。结论中性盐雾试验环境下,达到相同的最大蚀坑深度,2A97铝合金与AA2024铝合金用时基本相当。
Objective To research the relationship between maximum corrosion pit depth in aluminium alloy and environmental testing time to provide technology foundation for corrosion resistance evaluation for new alloys prior to service and life prediction of structures during service. Methods The types of corrosion of a new aluminium alloy in marine atmosphere were analyzed with optical microscopy and SEM. The relationship between maximum corrosion pit depth in aluminium alloy foil and testing time was studied with the foil penetration technique. Results Severe pitting occurred and developed deep into the 2 A97 aluminium alloy substrate after exposure in marine atmosphere. Time of foil penetration during environmental testing could be determined by examination the time of appearance of electrolyte from the back of the foil. After measurement of the penetration time of foils in various thicknesses, the relationship between the depth of the fastest growing corrosion pit and time could be determined. Conclusions In neutral salt fog testing environment, it generally takes the same time for 2 A97 aluminium alloy and AA2024 aluminum alloy to reach the same maximum corrosion depth.
Objective To research the relationship between maximum corrosion pit depth in aluminium alloy and environmental testing time to provide technology foundation for corrosion resistance evaluation for new alloys prior to service and life prediction of structures during service. Methods The types of corrosion of a new aluminium alloy in marine atmosphere were analyzed with optical microscopy and SEM. The relationship between maximum corrosion pit depth in aluminium alloy foil and testing time was studied with the foil penetration technique. Results Severe pitting occurred and developed deep into the 2 A97 aluminium alloy substrate after exposure in marine atmosphere. Time of foil penetration during environmental testing could be determined by examination the time of appearance of electrolyte from the back of the foil. After measurement of the penetration time of foils in various thicknesses, the relationship between the depth of the fastest growing corrosion pit and time could be determined. Conclusions In neutral salt fog testing environment, it generally takes the same time for 2 A97 aluminium alloy and AA2024 aluminum alloy to reach the same maximum corrosion depth.
引文
[1]BURLEIGH T D.The Postulated Mechanisms for Stress Corrosion Cracking of Aluminum Alloys:A Review of the Literature 1980-1989[J].Corrosion,1991,47(2):89-98.
[2]WALL F D,STONER G E.The Evaluation of the Critical Electrochemical Potentials Influencing Environmentally Assisted Cracking of Al-Li-Cu Alloys in Selected Environments[J].Corrosion Science,1997,39(5):835-853.
[3]CONDE A,FERNANDEZ B J,DE DAMBORENEA J J.Characterization of the SCC Behaviour of 8090 Al-Li Alloy by Means of the Slow-strain-rate Technique[J].Corrosion Science,1998,40(1):91-102.
[4]BAYOUMI M R.The Mechanics and Mechanisms of Fracture in Stress Corrosion Cracking of Aluminium Alloys[J].Engineering Fracture Mechanics,1996,54(6):879-889.
[5]NAJJAR D,MAGNIN T,WARNER T J.Influence of Critical Surface Defects and Localized Competition between Anodic Dissolution and Hydrogen Effects during Stress Corrosion Cracking of a 7050 Aluminium Alloy[J].Materials Science and Engineering A,1997,238(2):293-302.
[6]FRANKEL G S.Pitting Corrosion of Metals:A Review of the Critical Factors[J].Journal of The Electrochemical Society,1998,145(6):2186-2198.
[7]SEHGAL A,LU D,FRANKEL G S.Pitting in Aluminum Thin Films:Supersaturation and Effects of Dichromate Ions[J].Journal of The Electrochemical Society,1998,145(8):2834-2840.
[8]刘治国,颜光耀,吕航.7B04铝合金服役环境下点蚀表面损伤特征研究[J].环境技术,2017,35(5):46-49.
[9]HUNKELER F,BOHNI H.Determination of Pit Growth Rates on Aluminum Using a Metal Foil Technique[J].Corrosion,1981,37(11):645-650.
[10]骆晨,ALBU S P,孙志华,等.硼酸-硫酸阳极氧化2A97 Al-Cu-Li合金在热带海洋大气环境中的初期腐蚀机理[J].材料工程,2016,44(9):8-15.
[11]骆晨,王强,孙志华,等.热带海洋大气环境下2A97铝锂合金的初期腐蚀机理[J].腐蚀与保护,2015,36(Z2):49-54.
[12]刘明,蔡健平,孙志华,等.7B04铝合金海洋性大气腐蚀研究[J].装备环境工程,2010,7(6):163-166.
[13]HASHIMOTO T,ZHANG X,ZHOU X,et al.Investigation of Dealloying of S Phase(Al2CuMg)in AA 2024-T3Aluminium Alloy Using High Resolution 2D and 3DElectron Imaging[J].Corrosion Science,2016,103:157-164.
[14]孙霜青,郑弃非,李德富,等.LY12铝合金的长期大气腐蚀行为[J].中国腐蚀与防护学报,2009,29(6):442-446.
[2]WALL F D,STONER G E.The Evaluation of the Critical Electrochemical Potentials Influencing Environmentally Assisted Cracking of Al-Li-Cu Alloys in Selected Environments[J].Corrosion Science,1997,39(5):835-853.
[3]CONDE A,FERNANDEZ B J,DE DAMBORENEA J J.Characterization of the SCC Behaviour of 8090 Al-Li Alloy by Means of the Slow-strain-rate Technique[J].Corrosion Science,1998,40(1):91-102.
[4]BAYOUMI M R.The Mechanics and Mechanisms of Fracture in Stress Corrosion Cracking of Aluminium Alloys[J].Engineering Fracture Mechanics,1996,54(6):879-889.
[5]NAJJAR D,MAGNIN T,WARNER T J.Influence of Critical Surface Defects and Localized Competition between Anodic Dissolution and Hydrogen Effects during Stress Corrosion Cracking of a 7050 Aluminium Alloy[J].Materials Science and Engineering A,1997,238(2):293-302.
[6]FRANKEL G S.Pitting Corrosion of Metals:A Review of the Critical Factors[J].Journal of The Electrochemical Society,1998,145(6):2186-2198.
[7]SEHGAL A,LU D,FRANKEL G S.Pitting in Aluminum Thin Films:Supersaturation and Effects of Dichromate Ions[J].Journal of The Electrochemical Society,1998,145(8):2834-2840.
[8]刘治国,颜光耀,吕航.7B04铝合金服役环境下点蚀表面损伤特征研究[J].环境技术,2017,35(5):46-49.
[9]HUNKELER F,BOHNI H.Determination of Pit Growth Rates on Aluminum Using a Metal Foil Technique[J].Corrosion,1981,37(11):645-650.
[10]骆晨,ALBU S P,孙志华,等.硼酸-硫酸阳极氧化2A97 Al-Cu-Li合金在热带海洋大气环境中的初期腐蚀机理[J].材料工程,2016,44(9):8-15.
[11]骆晨,王强,孙志华,等.热带海洋大气环境下2A97铝锂合金的初期腐蚀机理[J].腐蚀与保护,2015,36(Z2):49-54.
[12]刘明,蔡健平,孙志华,等.7B04铝合金海洋性大气腐蚀研究[J].装备环境工程,2010,7(6):163-166.
[13]HASHIMOTO T,ZHANG X,ZHOU X,et al.Investigation of Dealloying of S Phase(Al2CuMg)in AA 2024-T3Aluminium Alloy Using High Resolution 2D and 3DElectron Imaging[J].Corrosion Science,2016,103:157-164.
[14]孙霜青,郑弃非,李德富,等.LY12铝合金的长期大气腐蚀行为[J].中国腐蚀与防护学报,2009,29(6):442-446.