Accelerated evolution of hydrogen from metals during plastic deformation

Plastic deformation accelerates the release of hydrogen from iron, Type 304L stainless steel, nickel, Inconel 718, and 5086 aluminum. The release rate is strain dependent: it increases rapidly when plastic deformation begins, reaches a maximum, and then decreases with additional strain with a final large release at fracture. The release rate is constant during Lüder’s extension for iron, and fluctuates coincidentally with the serrated flow of 5086 aluminum. The release rate during deformation also depends on temperature and strain rate. The accelerated release rate during deformation is discussed in terms of hydrogen-dislocation interactions and is interpreted as being caused by the egress of of dislocations and their associated hydrogen atmospheres during plastic deformation.