A Critical Examination and Quantitative Evaluation of the Role of Corrosion-Deformation Interaction in Environmentally-Assisted Cracking

摘要

The role of deformation mechanics (i.e., strain rate) has been emphasised in recent stress corrosion cracking (SCC) and corrosion fatigue (CF) investigations, especially in relation to anodic dissolution and / or film rupture mechanisms believed to be responsible for the SCC/CF in many material-environment systems of practical interest. In some cases, it appears likely that a similar role is played in the kinetics of cracking where influence of hydrogen is suspected in the SCC.One objective of this paper is to examine critically this role with a review of key observations from the laboratory and in-service experiences, as wel as published literature of other investigators, drawing upon the common basis and relations applicable to the many systems of engineering alloys in various environments. The review also focuses on the prominent mechanisms of the interaction between local or elemental processes of deformation and corrosion. The second objective is to present and discuss the more recent development and results of application of a quantitative model to characterise the initiation and propagation of environmentally assisted cracking in Ni-Cr-Fe Alloy 600 in water. It is shown that the modelling based on an integrated approach that takes into account the corrosion-deformation interaction effects can be useful. A general conclusion is drawn that much more systematic and consistent use of the presented common basis and corrosion-deformation interaction concepts is still needed, and can be promising, in the correct interpretation of data and service experience, and in its effective incorporation in the evgaluation of environmentally assisted cracking of engineering components.