Issue 78

A. Sancak et alii, Fracture and Structural Integrity, 78 (2026) 186-206; DOI: 10.3221/IGF-ESIS.78.11

inclined fracture surfaces, local shear-like regions and irregular edges near the fractured ligament. These observations are consistent with the scatter observed in the Charpy results. In particular, specimens tested under nominally identical conditions did not always exhibit identical macroscopic fracture appearances. However, these observations alone do not establish the cause of the differences in absorbed impact energy.

Figure 9: Stereomicroscope fracture-surface observations of uncorroded reference Charpy V-notch specimens at a) 0 °C, b) -20 °C, c) 23 °C, d) -40 °C temperatures. The images show the macroscopic fracture-surface appearance and specimen-to-specimen variation under different test-temperature conditions. Both seawater and substitute seawater specimens showed visible surface degradation in the stereomicroscope images. However, the macroscopic appearance did not show a direct one-to-one relation with the absorbed impact energy. Seawater generally produced higher mass loss than substitute seawater, but this difference was not always reflected by a proportional difference in Charpy energy. For this reason, the stereo images should be used as supporting evidence of surface degradation and fracture appearance rather than as a direct predictor of impact energy.

Figure 10: Stereomicroscope observations of Charpy V-notch specimens tested at 0 °C as a) uncorroded, b) group 5, c) group 7, d) group 8. The images show the macroscopic fracture-surface appearance after immersion in seawater and substitute seawater.

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