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FAILURE MECHANISMS IN IMPACT FATIGUE OF METALS
Author(s) -
IGUCHI H.,
TANAKA K.,
TAIRA S.
Publication year - 1979
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.1460-2695.1979.tb01352.x
Subject(s) - materials science , stress concentration , scanning electron microscope , nucleation , composite material , fatigue limit , fatigue testing , fracture (geology) , stress intensity factor , crack closure , fractography , fracture mechanics , chemistry , organic chemistry
Impact fatigue tests were performed with smooth and notched specimens of low carbon steels under various impact loading conditions. The characteristic failure mechanisms in impact fatigue was discriminated by comparison with those in non‐impact, ordinary fatigue. The fatigue life of smooth specimens was uniquely related to the range of plastic strain at the middle of the fatigue life in both impact and non‐impact fatigue, although the characteristics of micro‐structural deformation and cyclic stress‐strain relationships were markedly different. The growth rate of a fatigue crack in impact fatigue of notched specimens was higher than that in non‐impact fatigue when compared at the same stress intensity factor. Fractographic observations with scanning electron microscopy and the X‐ray diffraction technique revealed more abundant cleavage facets and a smaller spread of the plastic zone beneath the fracture surface made by impact fatigue. Both nucleation and propagation lives in notched specimens were much shorter in impact fatigue than in non impact fatigue when compared at the same values of nominal stress and stress concentration factor.