Assessment of hydrogen embrittlement on advanced high strength steels revealed by in-situ electrochemical micro-cantilever bending test

Abstract

In the current study, the hydrogen-induced embrittlement on advanced high strength steels (AHSSs) is evaluated by in-situ electrochemical microcantilever bending (IECB) tests. Microcantilevers of 1200 M and 1400 M steels were bent while hydrogen charged inside a miniaturized electrochemical cell and then compared to bent-cantilevers in the air. The results of bending experiments and post-mortem evaluation of the bent-cantilevers showed that the plastic deformation occurred for the bent-cantilevers in the air. At the same time, the reduction of yield stress and the formation of hydrogen-enhanced cracking happened for the hydrogen-charged cantilevers. The results indicated that the microcracks are initiated and propagated adjacent to the clamped boundaries of the cantilevers, where the stress intensity is topmost. This finding is demonstrated by created step-wise cracks in 1400 M representative bent cantilever. The results show that the hydrogen-enhanced dislocation nucleation and hydrogen-reduced dislocation mobility are responsible for plastic deformation and hydrogen-enhanced cracking behavior. • The effect of hydrogen on advanced high strength steels was evaluated by micro-cantilever bending tests. • Plastic deformation occurred for the bent-cantilevers in the air. • Hydrogen assisted cracking happened due to hydrogen dislocation interactions. • Cracks were initiated and propagated beside the clamped boundaries of the cantilevers.