1. Industrial manifestations of embrittlement problems

The classification adopted in this article for the various FPH phenomena is illustrated in figure 1 .

A distinction is made between situations where hydrogen may pre-exist in sufficiently large quantities in the material at the time of damage, in which case we speak of an internal hydrogen source, and cases where hydrogen is supplied by an external source. In the latter case, a distinction is made between high and low hydrogen activity. High hydrogen activity corresponds to conditions in which large quantities of hydrogen can be introduced into the material....