Dynamic behavior of hydrogen desorption from pure iron and inconel 625 during elastic and plastic deformations

Abstract

Dynamic behavior of hydrogen desorption from pure iron with a body-centered-cubic lattice and Inconel 625 with a face-centered-cubic lattice was examined during tensile deformation using a quadrupole mass spectrometer in a vacuum chamber integrated with a tensile testing machine. Hydrogen desorption from hydrogen-charged specimens was detected under various strain rates and cyclic stresses. Hydrogen desorption rarely increased under elastic deformation. In contrast, it increased rapidly at the proof stress when plastic deformation began, reached its maximum, and then decreased gradually with increasing applied strain for both pure iron and Inconel 625. This desorption behavior is closely related to hydrogen dragging by moving dislocations. The thermal desorption analysis results showed that the amount of desorbed hydrogen differed at each strain rate. This difference in the amount of desorbed hydrogen transported by dislocations depends on the balance between the hydrogen diffusion rate and mobile dislocation velocity.

Multiscale modelling of the interaction of hydrogen with interstitial defects and dislocations in BCC tungsten

“…An apparent synergy between deuterium retention and defect generation and evolution was reported in [53]. In [54], desorption of hydrogen was triggered by plastic deformation and the associated motion of dislocations. Also, a strong reduction of hydrogen diffusivity was predicted in the high hydrogen concentration limit [55].…”

Electrochemical hydrogen permeation measurement during cyclic stress testing of a ferritic chromium steel

“…Another transport-accelerating influence could act as a result of the increased dislocation velocity caused by the hydrogen-enhanced localized plasticity mechanism [7]. It is conceivable that, after the onset of plastic deformation, the transport of hydrogen is accelerated if it moves along with the dislocation [8,9].…”