The Effect of Environment on the Transition from Tensile Mode to Shear Mode During Fatigue Crack Growth in Aluminum Alloys. A Model for Environmentally Assisted Crack Growth

摘要

Fatigue crack propagation tests were carried out in different environments on 7075-T6 and 2024-T3 center-cracked sheet specimens. Observations were made on the transition from tensile mode to shear mode. It is shown that there is no unique correlation between the state of stress and the mode of cracking. Together with the state of stress the environment has a significant effect on the mode of cracking. The implications for crack growth under corrosion fatigue conditions as well as the fatigue mechanism are discussed.