Environmentally Assisted Cracking Measurements in Structural Aluminum Alloys Under Accelerated Test Conditions

Environmentally assisted cracking (EAC) of aluminum alloys in corrosive atmospheres is an important maintenance and safety issue for U.S. Department of Defense assets. EAC initiation and propagation of cracks is influenced by the complex interactions of load, environment, and alloy properties. Traditional environmental fracture testing conducted under immersion or constant humidity conditions may produce results that are different than measurements collected under thin electrolyte layers or droplets formed during atmospheric exposure. In addition, most standard methods do not provide instantaneous measures of crack velocity that can be used to identify specific environmental conditions that promote cracking. Improved assessment of EAC susceptibility and the conditions that promote cracking of aluminum alloys has been accomplished with an autonomous, in situ measurement system that can be used in accelerated corrosion test chambers and outdoor exposure sites. Continuous measurements of crack length through...