Three Dimensional Fractography of Extruded Age-Hardened Al Alloys Subjected to Fatigue Tests

Observation of fracture surface in metal fatigue is one of the most significant procedures to get insight into the cause and mechanism of crack initiation and propagation. In the present study, age-hardened 2017-T4 and 7075-T6 Al alloys having the extrusion texture were fatigue tested in low and high humidities, and their fracture surfaces were examined using a three dimensional (3D) surface analyzer. In addition to the microscopic observations conducted, it is shown that these 3D analyses provide important information on the difference in crack propagation depending on the stress level and environment.