Acoustic Emission Characterization of Corrosion Reactions in Aluminum Alloys

A description of characteristic acoustic emission (AE) generated in aluminum alloys exposed to various corrosive environments is presented. Several different microacoustic corrosion processes are considered, including hydrogen bubble evolution, general corrosion, pitting, crevice corrosion, and stress corrosion cracking. Broadband detection and digital recording of AE are used to provide information on AE frequency and waveform characteristics, which are then related to active corrosion reactions to provide AE source mechanisms. Scanning electron microscopy (SEM) studies performed on corroded specimens are used to further identify AE source mechanisms.