Hydrogen-induced hardening of a high-manganese twinning induced plasticity steel

High-manganese twinning-induced plasticity (TWIP) steels exhibit high strain hardening, tensile strength, and ductility, which make them attractive for structural applications. At low rates, TWIP are prone to hydrogen embrittlement (HE). Here though, we study the hardening strengthening resulting from electrochemical hydrogen-charging of a surface layer Fe-26.9Mn-0.28C (wt.%) steel. We observed 20% increase in yield strength following hydrogen-charging, accompanied by reduction ductility 75% 10% at rate 10−3s−1. The microstructural evolution during deformation was examined levels 3%, 5% 7% electron backscatter diffraction (EBSD) channeling contrast imaging (ECCI) dislocation structure hardened region. As expected, microstructure hydrogen-hardened uncharged regions material evolve differently. areas show entangled structures, indicating slip limited number potentially coplanar systems. In contrast, segregated grain boundaries, revealed deuterium-labelled atom probe tomography, delays nucleation blocking sources boundaries. charged hence first formation cells, entanglement more non-coplanar With increasing strain, these cells dissolve, stacking faults strain-induced ε-martensite formed, promoted presence hydrogen. influence on structures overall mechanism is discussed details.