Numerical approach to the I-S effect in ferritic heat-resisting steels

The change in hydrostatic pressure of an edge dislocation due to its solute atmosphere, the probability of finding substitutional-interstitial atoms pair (I-S pair) and the stress necessary for a dislocation to drag its solute atmosphere were calculated numerically for the ternary systems of Fe-9at.%Cr-0.1at.%N and Fe-1.2at.%Mo-0.1at.%N ferritic steels. Calculations showed the ratio of I-S pairs to total substitutional atoms is quite small, however, the maximum dragging stress increases greatly by the presence of a small amount of I-S pairs.