The effect of history on hydrogen assisted cracking: 2. A revision of K-dominance

摘要

In Part 1 of this work it was shown that, because of the coupling of the processes of crack growth and hydrogen accumulation in rupture sites, the crack growth kinetics curve nu = nu(K) in hydrogen assisted cracking (HAC) does not possess intrinsic uniqueness as a material's characteristic curve. This paper presents an analytical treatment of the phenomenon and a special regime of steady-state crack growth is seen to exist for which hydrogen assisted cracking turns out to be a K-dominated process. The corresponding plot of the steady-state nu against K acquires the uniqueness of a material's characteristic curve which may be used in engineering to provide more conservative evaluation of material resistance and structural integrity in HAC conditions. Inherent uncertainties in the customary fracture mechanics approach to HAC are analysed in an attempt to guide the way towards its further refinement. [References: 23]