| dc.description.abstract | This research presents the effect of different nature aging time (without aging, 1day, 4day) ,which the process is between solution treatment and T7 artificial aging ,on the resistance of stress corrosion cracking of high strength A201(Al-Cu-Ag-Mg) aluminum alloys , the analyzed methods including optical microscope (OM), electrical conductivity meter (% IACS), tensile test...ellipses.
It shows that the clustering of precipitation atoms in the aluminum alloy base will be enhanced when the natural aging time is increased from 1 day to 4 days. Compared to quenched-state alloys, the conductivity of alloys decreased about 5.5% and 6.2% respectively after 1day and 4days natural aging while the peak area of DSC increased about 36% and 37% and the hardness increased 40% and 54%. Compared to nature aging state(without aging, 1day, 4days), the conductivity of the alloy increased by 6.5%, 12.7% and 13.4% after T7 artificial aging while the hardness increased by 112%, 53% and 30% respectively. The resistance of the stress corrosion cracking (SCC) of the alloy were analyzes by slow strain rate tensile test in seawater. The results showed the resistance of SCC were improved significantly with the increasing time of nature aging.The ductility loss rate was 28% of the alloy without natural aging and the rate of natural aging alloys(1 day and 4 days) were both 5%. The tensile strength loss rate was 15% of the alloy without natural aging and the rate of natural aging alloys(1 day and 4 days) were both 3%.
The results showed natural aging is important to improve the resistance of SCC for the A201-T7. Microstructure (electrical conductivity meter, DSC), mechanical properties and the resistance of SCC ability shows no different with the natural aging 1 day and 4 days for the A201-T7.
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