Micromechanics of high temperature hydrogen attack

Hydrogen attack is a material degradation process that occurs at elevated temperatures in hydrogen-rich environments, such as found in petro-chemical installations. Weldments in components such as reactor vessels are particularly susceptible to hydrogen attack. This paper discusses a multi-scale micromechanics modeling approach in which the chemico-mechanical damage processes at sub-micron scale are coupled to the macroscopic behavior through a series of size-scale transitions. A simulation of hydrogen attack in a welded reactor serves as an illustration of the approach.