Effect of retrogression and reaging heat treatment on corrosion fatigue crack growth behavior of AA7050 alloy

Download
index.pdf
2004
Akgün, Nevzat
Show full item record
204
views
81
downloads
The effect of retrogression and reaging heat treatment on corrosion fatigue crack growth behavior on AA7050 T73651 aluminum alloy is investigated. CT (Compact Tension) specimens are prepared in LS direction for fatigue crack growth tests . Samples are solution heat treated at 477 °C and aged at 120 °C for 24 h (T6 condition). After that, samples are retrogressed at 200 °C for times of 1, 5, 30, 55 and 80 minutes in a circulating oil bath. Then, samples are re-aged at 120 °C for 24 h (T6 condition). Hardness measurements are taken at different retrogression times and at the end of the heat treatment. Fatigue crack growth tests are performed at as received condition and at different retrogression times with sinusoidal loading of R=0.1 and f=1 in both laboratory air and corrosive environment of 3.5% NaCl solution. The highest fatigue crack growth resistance is observed for 30 min. and 5 min. retrogression for laboratory air and corrosive environment respectively. It is concluded that RRA can successfully be used to improve fatigue performance of this alloy.
Metallurgy.
http://etd.lib.metu.edu.tr/upload/3/12605332/index.pdf
https://hdl.handle.net/11511/14513
Graduate School of Natural and Applied Sciences, Thesis

Suggestions

Effect of TiH2 particle size on foaming of aluminium
Kubilay, Ceylan; Öztürk, Tayfur; Department of Metallurgical and Materials Engineering (2005)
A study is carried out on the production of aluminum foams via powder processing. The study deals mainly with the effect of TiH2 particle size on the process of foaming. Mainly two TiH2 particle sizes were used; namely 27,5 ?m and 8,5 ?m. Foaming experiments were carried out at temperatures between 675oC ا 840oC. The viscosity of the system is adjusted by controlled addition of Al2O3. The study shows that choice of foaming agent size is influential in the foaming process. With the use of fine foaming agent,...
Investigation of the effect of orientation and heat treatment on the stress corrosion cracking susceptibility of 7050 aluminium alloy
Çevik, Gül; Doruk, Mustafa; Department of Metallurgical and Materials Engineering (2004)
In the present work, the effect of variation in specimen orientation and heat treatment on the Stress Corrosion Cracking (SCC) susceptibility of 7050 aluminum alloy was investigated in 3,5% NaCl solution and under freely corroding conditions. For this purpose, Constant Extension Rate Tests (CERT) was performed on precracked Compact Tension (CT) specimens and the Direct Current Potential Drop technique was applied to measure the crack lengths. In addition to crack length versus time curves, the relationship ...
Determination of susceptibility to intergranular corrosion in AISI 304L and 316L type stainless steels by electrochemical reactivation method
Aydoğdu, Gülgün Hamide; Aydınol, Mehmet Kadri; Department of Metallurgical and Materials Engineering (2004)
Austenitic stainless steels have a major problem during solution annealing or welding in the temperature range of 500-800 °C due to the formation of chromium carbide, which causes chromium depleted areas along grain boundaries. This means that the structure has become sensitized to intergranular corrosion. Susceptibility to intergranular corrosion can be determined by means of destructive acid tests or by nondestructive electrochemical potentiokinetic reactivation (EPR) tests. The EPR test, which provides q...
Fatigue crack growth behaviour of AA6013 aluminum alloy at different aging conditions
Varlı, Aziz Egemen; Gürbüz, Rıza; Department of Metallurgical and Materials Engineering (2006)
The effect of different aging treatments on fatigue crack growth behavior of AA6013 aluminum alloy was investigated. C(T) (Compact Tension) specimens were prepared in L-T and T-L direction for fatigue crack growth tests. Samples were in T651 as received, T42 which is solution heat treated at 538 ºC for 90 minutes, water quenched and aged in room temperature for 96 hours, and one group of samples were overaged at 245 ºC for 12 hours after T42 condition was achieved. Hardness and conductivity measurements wer...
The effect of austempering parameters on impact and fracture toughness of din 35nicrmov12.5 gun barrel steel
Aksu, Engin; Atala, Haluk; Department of Metallurgical and Materials Engineering (2005)
In this study the effects of different austempering times and temperatures on impact toughness, hardness and fracture toughness properties of 35NiCrMoV12.5 gun barrel steel are investigated. 300 °C, 325 °C and 350 °C were chosen as austempering temperatures. Isothermal holding times at these temperatures were chosen as 1 minute, 10 minutes, 1 hour and 10 hours. It was found that, 350 °C being an exception, austempering temperature and impact toughness has an inverse relationship and impact toughness increas...
Citation Formats
N. Akgün, “Effect of retrogression and reaging heat treatment on corrosion fatigue crack growth behavior of AA7050 alloy,” M.S. - Master of Science, Middle East Technical University, 2004.
METU IIS - Integrated Information Service open@metu.edu.tr