Effect of temper on the distribution of pits in AA7075 alloys

A comparative study of pitting severity in T6 and T73 tempers of AA7075 in 0.1 M NaCl is reported here. Pitting was more severe for T6 tempers compared to T73 tempers. This could be attributed to higher pit nucleation sites in the former. The statistical distributions for pit areas indicated nucleation saturation in T73. The extreme value distributions showed differences for the two tempers. These differences in pit distribution are explained on the basis of the role of constituent as well as strengthening particles as well as the role of grain boundary η precipitates.