PSI - Issue 76

R. Fernandes et al. / Procedia Structural Integrity 76 (2026) 43–49

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Fig. 2. Porosity relationship between equivalent diameter vs sphericity of pores.

3. Results and discussion Figure 3 shows the fatigue crack growth rate curves for as-built and stress-relieved specimens under the overload ratio 2. This figure compares the fatigue crack growth rates under single overloads at the stress intensity factors (ΔK OL = 4, 7 and 9 MPa√m).

Fig. 3. Fatigue crack growth rate curves for as-built and stress-relieved specimens at overload ratio of 2.0.

For the stress-relieved specimen, all overloads caused a reduction in fatigue crack growth rates, with retardation zones of 0.270 mm, 0.520 mm and 0.860 mm, for the first, second and third overloads, respectively. For the as-built