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IN SITU SEM MEASUREMENTS OF CRACK CLOSURE FOR SMALL FATIGUE CRACKS IN ALUMINIUM 2024‐T351
Author(s) -
Hallday M. D.,
Poole P.,
Bowen P.
Publication year - 1995
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.1460-2695.1995.tb00896.x
Subject(s) - materials science , crack closure , aluminium , composite material , paris' law , aluminium alloy , grain size , stress concentration , crack growth resistance curve , metallurgy , fracture mechanics
Crack closure has been measured for a range of small, self‐initiated fatigue cracks using in situ SEM loading. Cracks were grown at positive R ratios in the aluminium alloy 2024‐T351 and at nominal Δ K levels that extend substantially below the corresponding long crack threshold. The crack closure stress of the small cracks decreased and the K cl level increased with increasing crack size until the long crack value near threshold was reached. For cracks of depth larger than about one grain size, a good correlation was obtained between small and long crack growth rate data in terms of Δ K eff