Further study of the hydrogen embrittlement of martensitic advanced high-strength steel in simulated auto service conditions

Highlights: • Susceptibility increased at increasingly negative potentials and at lower pH in 3.5% NaCl. • Susceptibility increased at high charging potentials in 0.1 M NaOH at substantial stress rates. • The hydrogen influence was manifested by reduced ductility and brittle fracture features. - Abstract: This work examines the influence of hydrogen on the mechanical and fracture properties of martensitic advanced high-strength steels under conditions relevant to automotive service: (i) in 3.5 wt% NaCl at different cathodic potentials, (ii) in acidified 3.5 wt% NaCl and (iii) at substantial stress rates. The hydrogen embrittlement susceptibility of the steels increases at (i) increasingly negative potentials and at lower pH in 3.5 wt% NaCl, and (ii) at high charging potentials in 0.1 M NaOH at substantial stress rates. The hydrogen influence is manifested by a reduction in ductility, and the presence of brittle features on the fracture surface.