Effect of Zinc Addition on Static- and Dynamic-SCC Properties of Al-Li-Cu 2090 Alloy

A series of stress corrosion cracking (SCC) tests was carried out on the peak-aged Al-Li-Cu 2090 alloy plates to examine the effect of zinc addition on static- and dynamic-SCC properties. The alloy with 0.7% Zn addition showed an improved static-SCC resistance in the S-L direction. The reference 2090 alloy exposed to aqueous sodium chloride solution exhibited an accelerated dynamic-SCC growth in the T-L direction, relative to exposure to laboratory air, while the alloy with Zn addition revealed a reduced environment-sensitive crack growth. The dynamic-SCC was transgranular, the crack path appearing tortuous, which is assumed resulting from localized planar slip associated with {110} texture and inhomogeneous distribution of T1 precipitates. It was found that Zn addition is effective in reducing the slip planarity and preferential dissolution along slip bands.