PSI - Issue 60

Gopal Sanyal et al. / Procedia Structural Integrity 60 (2024) 311–323 Author name / StructuralIntegrity Procedia 00 (2019) 000–000

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dislocations can interact with diffusing hydrogen, the effect ofsevere manifestation of HE by large loss of RA ductilityis similar at all current densities. Similarly, for fracture toughness testing, the representative load vs. Corrected load-line displacement curves have been compared between samples tested in air and in-situ (20 mA/cm 2 ) in Fig.7. The correction in load-line displacement was made by obtaining load-displacement curve for an uncracked C(T) specimen and subtracting the displacement data corresponding to each load. It is clear that presence of hydrogen under stress caused huge reduction in displacement, suggesting early failure.

Figure 7. Load – corrected load displacement plot obtained from fracture toughness test carried out in air and under in-situ electrochemical charging with current density of 20 mA/cm 2 .

The side view of the portions of samples after fracture toughness testing has been compared in Fig.8. For the sample tested in air, presence of deformed zone ahead of crack tip is visible, whereas for the in-situ tested specimen, crack growth and branching are seen without appreciable development of plasticity at the crack tip.The crack tip opening is also significantly smaller for in-situ tested fracture toughness sample. The corresponding fractographs have been shownin Fig.9.

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