Microscopic Investigation on the Effect of Corrosion Attack on the FailureBehaviour of Laminated Aluminium Alloys

摘要

Tensile specimens made from laminated 2024-T3 and 7475-T761 aluminium 0.3 mmthick sheets were mechanically tested in laboratory air after exposure to a salt spray fog. Additional test were performed on specimens prepared from 2024-T3 1 mm sheet, and on specimens made from 2024 and 7475 Alclad material. A degradation in the mechanical properties was found on both the laminate specimens and the specimens prepared from the 1 mm sheet. Little degradation in the mechanical properties has been observed on specimens prepared from the Alclad alloy. Some typical examples of the laminate tensile specimens were microscopically examined to identify the fracture behavior employing Scanning Electron Microscopy. The observations indicated that the residual mechanical properties after a long exposure to a salt spray fog were dominantly determined by the fracture thoughness of the (laminated) material.