Multiscale approaches to hydrogen-assisted degradation of metals

Hydrogen embrittlement (HE) is a serious and costly industrial problem that affects many commonly used structural metals. Given the wide range of service environments in which hydrogen may occur or be produced, this represents a very serious threat to the structural integrity of machinery and infrastructure in many industries. Despite having been studied for several decades, there is still little consensus regarding the underlying mechanisms for HE. Recently developed theoretical and experimental methods, which enable the evaluation of the influences of hydrogen on the mechanical behavior of metals at the nano-scale, are helping to elucidate new aspects of these mechanisms. However, an urgent need remains to develop tools for the prediction of the reliability and lifetime of materials and components affected by hydrogen. Critical to achieving this goal is the development of accurate descriptions of hydrogen–microstructure interactions under conditions relevant to those occurring in service. As these interactions occur at all length scales, this poses a true multiscale challenge (Fig. 1).