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THE EFFECT OF ENVIRONMENT ON THE GROWTH OF SMALL FATIGUE CRACKS
Author(s) -
LANKFORD J.
Publication year - 1983
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.1460-2695.1983.tb01136.x
Subject(s) - materials science , grain boundary , aluminium , moisture , nitrogen , growth rate , metallurgy , composite material , chemistry , microstructure , geometry , mathematics , organic chemistry
— The growth of “large” and “small” cracks in 7075–T6 aluminum is characterized in moist air and dry nitrogen. It is found that in both environments, the small cracks grow faster than large ones, but unlike large cracks, which grow much faster in air than in nitrogen, the small cracks extend in each environment at about the same average rate. The absence of environmental effect is found to be only apparent, a change to an inherently slower mode of growth in air offsetting the crack‐accelerating influence of moisture. Subsurface grain boundaries apparently retard microcrack growth in both environments. Possible rationales for the rapid growth of small cracks are discussed.