PSI - Issue 68

Berkehan Tatli et al. / Procedia Structural Integrity 68 (2025) 1140–1146

1144

Tatli and Yalcinkaya / Structural Integrity Procedia 00 (2024) 000–000

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Fig. 2: Size e ff ect on true stress-strain curves

(a) C 0 = 0 . 5wt ppm

(b) C 0 = 1 . 0wt pppm

Fig. 3: Hydrogen concentration contours for precharged hydrogen concentration levels of C 0 = 0 . 5 wt ppm and C 0 = 1 . 0 wt ppm. Left: Avg. GD = 0.124 mm Results, Right: Avg. GD = 1.240 mm Results

rise in hydrogen content. In contrast, for smaller grain diameters, the crack propagation pattern shifts significantly with increasing hydrogen concentration. This suggests that while ambient hydrogen does not fundamentally alter the primary intergranular failure mechanism, larger grain sizes cause the microstructure itself to play a more dominant role in governing the failure process.