Analyzing through-thickness corrosion homogeneity of stabilized AA5083 alloy after artificial sensitization

Abstract

Through-thickness corrosion homogeneity of stabilized AA5083 alloy thick plate was investigated. For the as-received stabilized plates, no differences in corrosion behavior are evident in the specimens from different sampling positions along the thickness direction. However, in the plates after sensitization, the specimen from the surface position (T/10, SP) exhibits the highest degree of sensitization (DoS) and stress corrosion cracking (SCC) susceptibility, indicating the through-thickness corrosion inhomogeneity. Compared with interlayer position (3T/10, IP) and center position (T/2, CP), the higher grain stored energy and richer high angle grain boundaries (HAGBs) in SP specimens promote the formation of β phases (Al₃Mg₂) during the sensitization process. It results in a high coverage of β phases in the SP specimen and therefore induces severe corrosion.