Figure 7
Schematic illustrations of the H-accelerated/decelerated fatigue crack growth (FCG): (a) stress intensity factor range ΔK < 15 MPa m1/2 for (a-1) δ-FG associated with transgranular cracking exhibiting no acceleration of FCG and for (a-2) CG associated with transgranular cracking exhibiting deceleration of FCG. (b) ΔK > 15 MPa m1/2 for (b-1) δ-FG associated with intergranular cracking along δ-decorated grain boundaries exhibiting substantial time-dependent acceleration of FCG and (b-2) CG associated with transgranular cracking exhibiting deceleration of FCG.
