Hydrogen embrittlement of twinning-induced plasticity steels: Contribution of segregation to twin boundaries

Metallic materials, especially steel, underpin transportation technologies. High-manganese twinning induced plasticity (TWIP) austenitic steels exhibit exceptional strength and ductility from twins, low-energy microstructural defects that form during plastic loading. Their high-strength could help light-weighting vehicles, hence cut carbon emissions. TWIP are however very sensitive to hydrogen embrittlement causes dramatic losses of toughness leading catastrophic failure engineering parts. Here, we examine the atomic-scale chemistry interaction with twin boundaries in a model steel by using isotope-labelled atom probe tomography, tritium avoid overlap residual hydrogen. We reveal co-segregation and, unexpectedly, oxygen coherent boundaries, discuss their combined role these promising steels.