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Fracture Mechanics Study on Stress Corrosion Cracking Behavior under Corrosive Environment

2013; Japan Society Mechanical Engineers; Volume: 7; Issue: 3 Linguagem: Inglês

10.1299/jmmp.7.341

1880-9871

Tomoyuki Fujii, Keiichiro TOHGO, Naohiro Ishizuka, Yoshinobu SHIMAMURA, Masahiro Takanashi, Yu Itabashi, Gen Nakayama, Yohei Sakakibara, Takashi Hirano,

Non-Destructive Testing Techniques

This paper deals with applicability of non-linear fracture mechanics to crack growth by stress corrosion cracking (SCC) under large-scale yielding and in a plastically deformed area. Crack growth test by compact tension specimen is carried out to evaluate crack growth rate under small-scale and large-scale yielding conditions. To evaluate the crack growth behavior from a crack initiated in a plastically deformed area, crack growth test is also carried out for a very short pre-crack in a plastically deformed four-point bending specimen. Conventional stress intensity factor (K) and equivalent stress intensity factor (KJ) defined by J integral are used as fracture mechanics parameters which characterize the crack growth rate. On da/dt-K diagram, a data band shows wide scatter, especially the crack growth rate in a plastically deformed area is higher than that under small-scale yielding condition. On the other hand, da/dt-KJ diagram exhibits narrower scatter on a data band than da/dt-K diagram. The equivalent stress intensity factor is appropriate for characterization of crack growth rate by SCC under small-scale yielding through large scale yielding conditions and in a plastically deformed area.