Hydrogen embrittlement is shown to occur very easily in notched round bars under opening mode I (tension) but not under antiplane shear mode III (torsion). The stress tensor invariants under mode I, II, and III loadings and how these asffect interstitial diffusion are discussed. It is suggested that long range diffusion of hydrogen down orthogonal trajectories to the vicinity of the crack tip, which can occur under mode I but not mode III, is a key part of any hydrogen embrittlement mechanism. This premise was evaluated with AISI 4340 steel.
|Original language||English (US)|
|Number of pages||6|
|State||Published - Jan 1 1973|