Our comprehensive historical review of the environment-induced cracking (EIC) of aluminum alloys over the last 80 years revealed that minimal attention has been focused on the initiation and early stages of crack development both for test samples and more importantly for aerospace structures constructed from AA7xxx alloys during either material development or during field exposure in service. This has led to both uncertainties for the development of reliable test methods, alloy and temper selection, and fabrication and joining methodologies that do not provoke EIC. Together this has resulted in repeated incidences of major service failures over the years.

The high-strength Al-Zn-Mg-Cu plate alloys, such as AA7050 and AA7010, used widely during the 1990s and the following two decades in aerospace applications, suffered little or no EIC during service use. These alloys were designed to provide “practical immunity” to EIC during use in structural aerospace applications, following lessons...

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