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dc.contributor.supervisor Beddoes, Jonathan (Mechanical Engineering) en_US
dc.contributor.author Tehinse, Olayinka
dc.date.accessioned 2014-08-26T22:02:58Z
dc.date.available 2014-08-26T22:02:58Z
dc.date.issued 2014-08-26
dc.identifier.uri http://hdl.handle.net/1993/23892
dc.description.abstract Al-Zn-Mg-Cu (7xxx series) aluminium alloys are widely used for aircraft structures. It is difficult to obtain a combination of optimal strength and stress corrosion cracking (SCC) resistance for these alloys. It appears that SCC resistance of these alloys is related to grain boundary precipitate morphology. One technique to control the grain boundary precipitate morphology is to introduce a controlled cooling procedure referred to as High Temperature Pre-precipitation (HTPP) treatment following the solution heat treatment. There is need for a detailed study of the effect of HTPP on the properties of commercial Al-Zn-Mg-Cu alloys using different intermediate temperatures. In this thesis research, the results of ten HTPP processes applied to 7075 and 7050 commercial 7xxx series alloys are presented in terms of hardness, electrical conductivity, corrosion resistance, TEM analysis of grain boundary precipitate morphology and EDS analysis of solute concentration profile at the grain boundary. Results indicate that subsequent to HTPP processing, the 7050 alloy can be precipitation aged to a higher hardness compared to 7075; this result is associated with the modification of 7050 alloy by zirconium versus chromium in 7075 alloy. HTPP heat treatment achieves better SCC resistance compared to standard T6 temper. However, it does not appear that HTPP can achieve a combination of hardness, electrical conductivity and corrosion resistance superior to standard T6 and T7X tempers. en_US
dc.subject High Temperature Pre-precipitation en_US
dc.subject Stress Corrosion Cracking en_US
dc.subject Exfoliation Corrosion en_US
dc.subject Electrical Conductivity en_US
dc.title Response of 7075 and 7050 aluminium alloys to high temperature pre-precipitation heat treatment en_US
dc.degree.discipline Mechanical and Manufacturing Engineering en_US
dc.contributor.examiningcommittee Bassuoni, Mohamed (Civil Engineering) Caley, William (Mechanical Engineering) en_US
dc.degree.level Master of Science (M.Sc.) en_US
dc.description.note October 2014 en_US


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