Mechanics and mechanisms of fatigue crack growth in metals: a review

The influence of alternating and mean stress intensity on fatigue crack propagation in metals has been studied in relation to the different microstructure, mean (or maximum) stress intensity and specimen thickness, particularly in the range of medium and high growth rates. The simple growth law da/dN = C Δ Ksup(m) was found to be obeyed with little variation in C and m for the striation mechanism of crack growth over a wide range of testing conditions. Modification of this law is necessary for very low and very high rates of propagation where non-striation (cleavage, intergranular, and void coalescence) mechanisms are involved. (author)