|About this Abstract
||2022 TMS Annual Meeting & Exhibition
||Environmentally Assisted Cracking: Theory and Practice
||EAC susceptibility of differently aged high zinc 7068 T6 alloy
||Ankur Kumar, G P Chaudhari, S K Nath
|On-Site Speaker (Planned)
Mechanism of localised pitting corrosion along with passivity breakdown in variously aged 7068 aluminium alloy in Cl− containing environment is investigated by using potentiodynamic polarization tests and Mott-Schottky analysis. XPS is used to determine the chemistry of the corrosion product. Findings support the passivity breakdown hypothesis of the point defect model (PDM). Various lattice conserving/non-conserving reactions at the metal/film and film/electrolyte interfaces are responsible for film formation and dissolution. Signature of Warburg impedance in the Nyquist plot shows that the concentration of cation vacancies (V_Al^(x^+ )), is the likely rate-determining factor. Investigation of SCC behaviour shows that anodic dissolution and hydrogen embrittlement are responsible for the failure. Among all the heat-treated conditions, T6-120 specimen showed superior mechanical, and electrochemical properties due to discontinuous grain boundary precipitates and formation of thicker and defect-lean passive film.
||Aluminum, Environmental Effects, Characterization