To achieve combined high strength and HE resistance, this work tailored incidental dislocation boundaries (IDBs) in high-Mn steels via cold-warm-rolling (CWR), versus low-angle-grain boundary (LAGB)-dominated warm-rolling (WR) samples. CWR samples shows a high yield strength (∼910 MPa), with an abnormal ductility enhancement (tensile elongation, 27% → 35%) after H pre-charging and retained ductility under in-situ H-charging, while WR samples suffer severe ductility loss. IDBs act as efficient H-traps and mediate microband-nanotwin synergy to inhibit hydrogen-induced cracks (HICs), whereas LAGBs and strong texture in WR induce coarse unidirectional microbands and rapid dislocation accumulations, triggering the occurrence of HICs at microband boundaries.
Li et al. (Mon,) studied this question.