Crack Paths 2009

10 -6 -5

Air,223K

Ambientair

Vacuum,R o o m T

Vacuum,223K

101-001-1098 -7

Ambient

DryCooled

Air

10-5

0.0001

∆

( )

b)

a)

Fig. 11: Influence temperature and air humidity on da/dN in 2024AT351[26]: a) da/dN

vs ∆Keff/E in air and high vacuum at 223K and room T; b) S E Mobservations of

fracture surface when environment is changed from ambient air to dry air at 223K.

Stade II intrinsèque

Stade II assisté par l'adsorption

10-65

Pseudo-StadeI

dewpoint =-50°C wp t 72°5C ambient air

(m / c y c le )

110

-9 10-8

0

d a / d N / d a / d N

d 10-7 a /d N

10

Adsorption

assisted stage II

10-110

10-5

10-4

Intrinsic stageII

Intrinsic stageI-like

10-310-2 10-1 100 101 102 103

Exposure(Paxs)

∆ K eff /E(m1/2)

a)

b)

Figure 12: Influence of air dryness (water vapor exposure) on da/dN for 2024AT351:

a) da/dN vs ∆K; b) (da/dN)dewpoint/(da/dNvacuum).

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