Crack Paths 2012

Figure 5. Fatigue crack growth curves.

Figure 6. Fatigue crack paths. (a) Base Material, (b) Weld Metal, (c) Heat Affected

Zone.

E X P E R I M E N TR AE SLU L T S

Fatigue CrackGrowthCurves

The fatigue crack growth curves are shown in Fig. 5. It can be noted that both W Mand

H A Zexhibit slower crack growth rates as compared to BM, especially in the near

threshold regime. This can be reasonably imputed to surface residual stresses,

introduced by the welding process both in W Mand H A Z(as attested by blind-hole

drilling measurements, here not reported for the sake of brevity), responsible for crack

closure and crack growth retardation. In addition, crack growth rates are even slower in

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