Interplay between H atoms and characteristic microstructure features in 2100 MPa grade full pearlite steel wire for bridge cable

L Jia and CY Hu and MJ Zhang and HY Dong and XX Zhu and L Cheng and HJ Xue and J Zhao and KM Wu, INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, 172, 151226 (2025).

DOI: 10.1016/j.ijhydene.2025.151226

The interaction among hydrogen atoms, dislocations, and pearlite lamellae in 2100 MPa grade full pearlite steel wire for bridge cables was comprehensively examined by the slow strain rate tensile (SSRT) test under various H sources (uncharged, UC; in-situ H-charged, IHC; ex-situ H-charged, EHC) and characterized by the scanning electron microscope (SEM), electron backscattered diffraction (EBSD) and high-resolution transmission microscope (TEM). The findings confirmed that the variation in fracture morphologies among UC, IHC, and EHC specimens arises from the influence of H. Tensile tests dominated by IHC will promote the formation of surface micro-cracks, while those dominated by EHC will promote the overall embrittlement of the fracture surface. As the specimens are predominantly influenced by environmental H, in contrast to those containing internal H, crack propagation is more reliant on strain and stress distribution during loading than on microstructure. Compared to specimens exposed solely to environmental hydrogen, those subjected to both environmental H and internal H exhibit nearly identical behavior, confirming the dominant role of environmental H in hydrogen embrittlement (HE) destruction. The diminished number density of dislocations is attributed to H-enhanced dislocation mobility, resulting from the H-induced reduction of dislocation activation stress.

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