Corrosion damage evolution of the aircraft aluminum alloy 2024 T3

Abstract

Purpose – The purpose of this paper is to quantify the corrosion damage evolution that has occurred on the aircraft aluminum alloy 2024 after the exposure to Exfoliation Corrosion Test (EXCO) solution. Moreover, the effect of the evolving corrosion damage on the materials mechanical properties has been assessed. The relevance of the corrosion damage induced by the exposure to the laboratory EXCO for linking it to the damage developed after the exposure of the material on several outdoor corrosive environments or in service is discussed. Design/methodology/approach – To induce corrosion damage the EXCO has been used. For the quantification of corrosion damage the metallographic features considered have been pit depth, diameter, pitting density and pit shape. The effect of the evolving corrosion damage on the materials mechanical properties has been assessed by means of tensile tests on pre corroded specimens. Findings – The results have shown that corrosion damage starts from pitting and evolves to exfoliation, after the development of intergranular corrosion. This evolution is expressed by the increase of the depth of attack, as well as through the significant growth of the diameter of the damaged areas. The results of the tensile tests performed on pre corroded material made an appreciable decrease of the materials tensile properties evident. The decrease of the tensile ductility may become dramatic and increases on severity with increasing corrosion exposure time. SEM fractography revealed a quasi-cleavage zone beneath the depth of corrosion attack. Originality/value – The results underline the impact of corrosion damage on the mechanical behavior of the aluminum alloy 2024 T3 and demonstrate the need for further investigation of the corrosion effect on the structural integrity of the material. This work provides an experimental database concerning the quantification of corrosion damage evolution and the loss of material properties due to corrosion.