AMraet-Fatigue
crack growth rate was found to be independent of grain size in 309!3 stainless steel, for grain sizes of 45 and 480 pm. The data were compared to literature results for a variety of stabk and mtstabie austerdtic alloys, and were shown to agree well, THE RECENT literature on fatigue crack growth under elastic-plastic conditions contains discussion on whether or how microstructure can affect crack growth ratefl-101. One factor in this discussion is the well-documented independence of growth rate and yield strength [1,4,1 l-141. One microstructural feature which can control strength is grain size, and it has been shown that growth rate is independent of grain size [9], as had been suggested in reviews of indirect evidence on grain size effects[lO, 151. Some data do exist, however, for AISI type 305 stainless steel&], which suggest a dependence of growth rate on grain size. It appeared worthwhile to see whether this result could be corroborated with another stainless steel.
Fatigue crack growth data are generally correlated with thi: stress intensity range, AK. A wide variety of experimental data have been found to fit a relation due $o