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380 M. FONTE ET AL.

55. Petit J.(1984) Some aspects of near threshold crack growth: microstructural and
environmental eflects. In: Fatigue Crack Growth Threshold Concepts, Davidson and
Suresh (Eds), TMS AIME pub, Philadelphia, 3-25.
56. Ricker, R.E. and Duquette, D.J.(1988) The role of Hydrogen in Corrosion Fatigue of
High Purity AI-Zn-Mg Exposed to Water Vapor. Metall Trans 19 A, 1775-1783.
57. Vasudthn, A.K. and Suresh, S. (1982) Influence of corrosion deposits on near-
threshold fatigue crack growth behavior in 2xrx and 7xrx series aluminum alloys.
Metall Trans A, 13 A, 2271-2280.

Appendix: NOMENCLATURE

a = crack length
dddN = fatigue crack growth rate
FCGR = fatigue crack growth rate
GB = grain boundary
GP = grain precipitate
K = stress intensity factor
AK = stress intensity range
= values of AK at threshold
K*,, and Kith = two threshold parameters
K,,, Kmin = values of K corresponding to Pmaxr P,i,
N = number of load cycles
P,,,, Pmi, = maximum and minimum loads applied in each cycle
R = Pmin/Pmx
SIF = stress intensity factor