It had previously been considered how the crack-blunting dislocation emission mechanism might lead to a Paris fatigue-crack growth-rate law exponent, n =2, if dislocation shielding was not important, and shown how dislocation crack-tip shielding could cause a reduction in the fatigue-crack growth-rate and how it might lead to an increase in the Paris exponent, n. Here, semi-quantitative calculations showed how the Paris exponent could be increased by dislocation shielding.

Dislocation Crack Tip Shielding and the Paris Exponent. J.Weertman: Materials Science and Engineering A, 2007, 468-470, 59-63