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Master Thesis on Environmental effect on intergranular corrosion of 2xxx Al alloys
In this project, a combined microscopic and electrochemical approach will be used to correlate the local surface reactivity of Al-Cu-Li alloys to specific microstructural features for a detailed characterization of corrosion processes at the microscale.
Keywords: Al alloy, 2xxx series, corrosion, electron microscopy, electrochemistry, scanning probe microscopy, microstructure evolution, ageing
In the current context of reducing weight in aerospace applications, driven by fuel, emission and energy reduction, interest for Al-Li alloys as structural materials, has constantly increased over the past few decades. In particular, the new Al-Cu-Li generation of alloys combines good mechanical properties with high resistance to uniform corrosion, which overcomes most of the limitations of the Al-Li alloy previous generations. However, their temper-dependent susceptibility to intergranular corrosion challenges their use in aircraft applications as replacement for conventional high strength Al alloys, as it may significantly affect the structure lifetime.
The atypical corrosion behaviour of Al-Cu-Li alloys is directly related to the changes in the grain boundary microstructure/microchemistry as function of isothermal aging. In this project, microscopic analysis combined with scanning electrochemical nanocapillary (SEN) and environmental scanning Kelvin probe force microscopy (AFM/SKPFM) approach will be used to correlate the local surface reactivity of Al-Cu-Li alloys to specific microstructural features for a detailed characterization of corrosion processes at the microscale. In particular, focus will be put on understanding the environmental interactions with the Al-Cu-Li alloy surface to efficiently predict its corrosion behaviour.
In the current context of reducing weight in aerospace applications, driven by fuel, emission and energy reduction, interest for Al-Li alloys as structural materials, has constantly increased over the past few decades. In particular, the new Al-Cu-Li generation of alloys combines good mechanical properties with high resistance to uniform corrosion, which overcomes most of the limitations of the Al-Li alloy previous generations. However, their temper-dependent susceptibility to intergranular corrosion challenges their use in aircraft applications as replacement for conventional high strength Al alloys, as it may significantly affect the structure lifetime. The atypical corrosion behaviour of Al-Cu-Li alloys is directly related to the changes in the grain boundary microstructure/microchemistry as function of isothermal aging. In this project, microscopic analysis combined with scanning electrochemical nanocapillary (SEN) and environmental scanning Kelvin probe force microscopy (AFM/SKPFM) approach will be used to correlate the local surface reactivity of Al-Cu-Li alloys to specific microstructural features for a detailed characterization of corrosion processes at the microscale. In particular, focus will be put on understanding the environmental interactions with the Al-Cu-Li alloy surface to efficiently predict its corrosion behaviour.
The project will be conducted in the Laboratory of Joining Technologies and Corrosion at Empa Dübendorf. The aim of the project is to determine the environmental effect on the corrosion behaviour of commercially available Al-Cu-Li alloy as a function of its aging condition. In particular, the following aspects should be investigated:
1) Fundamental correlation between microstructure evolution as a function of aging (grain orientation, precipitate, …) and corrosion behaviour
2) Environmental effect (atmospheric vs aqueous conditions) on local surface reactivity
3) Effect of hydrogen embrittlement on intergranular corrosion
At the end of the project, the candidate will have acquired some expertise in the fields of corrosion and material sciences. This project will also allow the candidate to strengthen his/her skills in electrochemical and surface characterisation, as well as being involved in the further development of a cutting-edge electrochemical technique, the scanning electrochemical nanocapillary (SEN).
The project will be conducted in the Laboratory of Joining Technologies and Corrosion at Empa Dübendorf. The aim of the project is to determine the environmental effect on the corrosion behaviour of commercially available Al-Cu-Li alloy as a function of its aging condition. In particular, the following aspects should be investigated: 1) Fundamental correlation between microstructure evolution as a function of aging (grain orientation, precipitate, …) and corrosion behaviour 2) Environmental effect (atmospheric vs aqueous conditions) on local surface reactivity 3) Effect of hydrogen embrittlement on intergranular corrosion At the end of the project, the candidate will have acquired some expertise in the fields of corrosion and material sciences. This project will also allow the candidate to strengthen his/her skills in electrochemical and surface characterisation, as well as being involved in the further development of a cutting-edge electrochemical technique, the scanning electrochemical nanocapillary (SEN).
If you are interested or want to learn more, please contact Dr. Noémie Ott (noemie.ott@empa.ch), daily supervisor or Dr. Patrik Schmutz (patrik.schmutz@empa.ch), group leader Functional Surfaces, Empa Dübendorf
If you are interested or want to learn more, please contact Dr. Noémie Ott (noemie.ott@empa.ch), daily supervisor or Dr. Patrik Schmutz (patrik.schmutz@empa.ch), group leader Functional Surfaces, Empa Dübendorf