水素ガス中におけるぜい性ストライエーション形成機構のシミュレーション

抄録

Hydrogen changes material strength and increases fatigue crack growth rate. In the study on the effect of hydrogen on material strength, the basic hydrogen embrittlement mechanism that hydrogen reduces interatomic bonding force and facilitates plastic deformation (literature) has been discussed. On the other hand, with regard to the fatigue crack growth mode, it has been reported that, depending on the test conditions, a transition from a ductile crack growth accompanied by ductile striation to a seemingly brittle crack growth accompanied by micro void formation and bonding at the crack tip is reported. In addition, a peculiar sexual fracture surface such as a grain boundary fracture surface or a pseudo-cleavage fracture surface is formed on the fatigue fracture surface. As a mechanism for explaining this, Nishikawa developed a brittle strike in which microscopic ductile crack growth (tearing) involving ductile fracture in front of the crack occurred and the crack progressed. The formation mechanism of the association was proposed. In this study, we analyzed the change in material strength due to hydrogen on the FEM using the hydrogen convection diffusion analysis devised by Sasaki simulation of fatigue crack propagation of Steel an attempt was made to reproduce the brittle striation formation mechanism proposed by Nishikawa on FEM.