Delamination of Sensitized Al-Mg Alloy During Fatigue Crack Growth in Room Temperature Air

Fatigue crack growth experiments in air at 295 K (22 °C) were conducted on 6.35 mm thick plate samples of a commercial Al-Mg alloy machined from the L-T orientation. Thermal exposures for times up to 2000 hours at 343 K, 353 K, 373 K, and 448 K (70 °C, 80 °C, 100 °C, and 175 °C) produced sensitization and delamination in the S-T plane during fatigue testing, dependent on the level of thermal exposure and Kmax employed. Identical tests conducted in a “dry” environment produced no delamination, indicating that environment may enhance the phenomena.