THE EFFECT OF HISTORY ON HYDROGEN-ASSISTED CRACKING - 1 - COUPLING OFHYDROGENATION AND CRACK-GROWTH

This paper analyzes the effect of process history on K-dominance condi tion in hydrogen assisted cracking. The performed study of stress-stra in assisted diffusion reveals that hydrogenation of the fracture proce ss tone is not a purely K-driven local autonomous phenomenon. Hydrogen ation and crack growth are shown to be coupled processes, one influenc ing the other. Consequently, particular histories of stress intensity factor K and crack size evolutions affect crack growth rate nu that ca n occur at the same instantaneous K-value in a given material. Thus th e crack growth kinetics curve nu = nu(K) is not unique as an intrinsic material property must be.