Micromechanical Modeling of Hydrogen Transport - A Review

Reviewing the mechanical aspects of stress corrosion cracking and hydrogen embrittlement almost 25 years ago, Rice [1, 2] indicated that an accurate analysis of hydrogen transport as affected by local stresses and strains is of primary importance toward understanding the conditions under which the mechanisms causing hydrogen embrittlement operate [3]. In 1980, Hirth in a review article [4] made it clear that trapping of hydrogen is a very important part of hydrogen embrittlement, and its significance lies behind the embrittling mechanisms. The purpose of this study is to review the models of hydrogen transport in non-hydride forming systems, and draw conclusions as regards to the hydrogen degradation effect. It should be pointed out that this review does not aim at identifying and quoting the entire literature on the subject, which is voluminous. In fact, there is a number of recent articles devoted on various specific issues of hydrogen transport, and related issues of trapping [5-12]. Rather, the effort will be directed toward providing the status of our current understanding of hydrogen transport, and in particular how solid mechanics methodology can help in this direction.