Publications Details

The role of anodic dissolution in the stress corrosion cracking of Al-Li-Cu alloy 2090

Buchheit Jr., R.G.; Wall, F.D.; Stoner, G.E.; Moran, J.P.

The short-transverse (S-T) stress corrosion cracking (SCC) behavior of Al-Li-CU alloy 2090 was studied using a static load SCC test technique. Time to failure was measured as a function of applied potential in several different environments. Rapid SCC failures (< 10 hours) were observed only when the following criteria were satisfied: E{sub br, T1} < E{sub applied} < E{sub br, matrix} where potentials refer to the breakaway potentials of the subgrain boundary T{sub 1} (Al{sub 2}CuLi) phase and the {alpha}-Al matrix phase. E{sub br} values were measured using potentiodynamic polarization of bulk materials intended to simulate the individual phases found in the subgrain boundary region. Results strongly suggest an anodic dissolution based SCC mechanism for this alloy where selective dissolution of T{sub 1} on the subgrain boundary is a critical step. The unusual pre-exposure embrittlement phenomenon demonstrated by Al- Li alloys is also shown to be consistent with these simple SCC criteria. 21 refs., 9 figs., 6 tabs.