Evolution of environment-induced cracking in commercial aluminum alloys: Crack arrest or growth?Thursday (07.11.2019) 08:30 - 09:10 Part of:
A review of the commercial use of higher-strength 5xxx series (Al-Mg) and 7xxx series (Al-Zn-Mg-Cu) aluminum alloys over the last 70 years or so reveals several cycles, where EIC related issues occur during service that subsequently are overcome by alloy product innovation.
Although aluminum alloys are immune to sustained-load cracking in dry gases, including diatomic hydrogen, they are often potentially susceptible to environment-induced cracking (EIC) when exposed to water vapour, moist gases, distilled water and various aqueous solution containing anions, including chloride, sulphate and nitrates.
It is interesting such a low frequency of EIC related issues occur during service for widely used alloys/tempers, suffering high environment-induced crack growth rates when subjected to relatively benign loading conditions during conventional accelerated laboratory testing.
A rationale will be presented to explain the discrepancies between laboratory investigations of EIC and service realities, and a why further research work is now needed to ensure/improve the EIC resistance for the next-generation of higher-strength alloys.