腐食ピットからの疲労き裂発生挙動について

抄録

Corrosion fatigue tests in 3% NaCl aqueous solution have been conducted on a low carbon steel, S10C, a stainless steel, SUS304, and an aluminum alloy, A2024-T4, in order to clarify their crack initiation behavior from corrosion pits. The size of corrosion pits at which crack was generated was plotted on a log-normal probability paper. It was found that the size of corrosion pits increased with decreasing stress level. The stress intensity factor of a corrosion pit at which crack initiation occurred was calculated by regarding the corrosion pit as a crack. The results were plotted on a log-normal probability paper, indicating that the stress intensity factor increased with increasing stress level in S10C and A2024-T4, but it was irrespective of stress level in SUS304. The stress intensity values obtained ranged 0.51-2.33MPa√m in S10C, 0.37-1.40MPa√m in SUS304 and 0.21-1.21MPa√m in A2024-T4.