Quantification of Mass Loss Dependence on Sample Orientation in 5xxx Series Aluminum Alloys

Abstract

ASTM G67 is the standard test method for determining the susceptibility to intergranular corrosion (IGC) of 5xxx series aluminum alloys and requires measuring mass loss after exposure to nitric acid (the nitric acid mass loss test, NAMLT). This mass loss, and thus the IGC susceptibility, is dependent on orientation of the wrought product, but the quantitative degree of this dependence has not been well studied or documented. The orientation dependence of IGC susceptibility for AA5083 (UNS A95083) in H131 and H116 tempers is quantitatively presented herein. The underlying mechanism behind this dependence is also explored.