Stress corrosion cracking behavior and mechanism of 2205 duplex stainless steel under applied polarization potentials.

In this work, a non-steady electrochemical model for assessing stress corrosion cracking (SCC) of 2205 duplex stainless steel (DSS) under applied polarization potentials was proposed, and the SCC mechanism was revealed. With the negative shift of potentials, hydrogen enhances SCC susceptibility by deteriorating passive film, inhibiting repassivation and causing serious damage. In particular, at −850 mV (vs. SCE), the synergetic effect of anodic dissolution (AD) and hydrogen embrittlement (HE) causes severe pitting and SCC. The negative shift of applied potentials changes the preferential pit/SCC initiation site due to high hydrogen concentration in austenite. • A non-steady electrochemical model for assessing SCC of 2205 duplex stainless steel was proposed. • The direct evidence was provided that the synergy of anodic dissolution and hydrogen embrittlement controls SCC. • The negative shift of potentials varies the initiation sites of pits and SCC because of hydrogen enrichment in austenite. [ABSTRACT FROM AUTHOR]