Hydrogen-assisted fatigue crack propagation in a pure BCC iron. Part I: Intergranular crack propagation at relatively low stress intensitiesYuhei Ogawa, Domas Birenis, Hisao Matsunaga, Osamu Takakuwa, Junichiro Yamabe, Øystein Prytz and Annett ThøgersenMATEC Web Conf., 165 (2018) 03011DOI: https://doi.org/10.1051/matecconf/201816503011