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DEPENDENCE OF ACOUSTIC EMISSION FOR LOW STRENGTH STEELS UPON THE EMBRITTLEMENT AND THE PLASTIC ZONE REDUCTION AT THE CRACK TIP DURING CORROSION FATIGUE CRACK PROPAGATION
Author(s) -
Wang Z. F.,
Li J.,
Ke W.,
Zhu Z.
Publication year - 1993
Publication title -
fatigue and fracture of engineering materials and structures
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 84
eISSN - 1460-2695
pISSN - 8756-758X
DOI - 10.1111/j.1460-2695.1993.tb00099.x
Subject(s) - materials science , acoustic emission , embrittlement , crack closure , ductility (earth science) , corrosion , corrosion fatigue , composite material , hydrogen embrittlement , fracture mechanics , fracture (geology) , metallurgy , creep
Acoustic emission signals were continuously monitored during fatigue crack propogation for two kinds of low strength steel placed in either laboratory air or 3.5% NaCl solution. The plastic deformation of the materials at the crack tips were compared by determining the changes in specimen geometry at the fracture surface in the thickness direction while the hydrogen distribution from the crack tip material was analysed by SIMS. The results showed that acoustic emission was less active in an aqueous solution than in air and that the plastic zone size was reduced in a corrosive medium. It was considered that the entrance of hydrogen into the crack tip during corrosion fatigue results in a decrease of material ductility, which lead to a low activity in acoustic emission.