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THE EFFECT OF INTERMEDIATE HEAT TREATMENTS ON OVERLOAD INDUCED RETARDATIONS DURING FATIGUE CRACK GROWTH IN AN Al‐ALLOY
Author(s) -
Ling M. R.,
Schijve J.
Publication year - 1992
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.1460-2695.1992.tb01284.x
Subject(s) - crack closure , materials science , paris' law , crack growth resistance curve , residual stress , crack tip opening displacement , fatigue testing , composite material , deformation (meteorology) , structural engineering , plasticity , metallurgy , fracture mechanics , engineering
— Crack growth fatigue tests were carried out on 2024‐T3 specimens. Constant‐amplitude loading was periodically interrupted by 10 overload cycles. Intermediate heat treatments (T4) were applied to remove the residual stress in the crack tip zone and the crack closure wake behind the crack tip. Retardation effects induced by crack closure due to the previous load history were fully erased by the heat treatments. Overload effects were easily introduced again by new overload cycles afterwards. Crack growth rate results and fractographic observations indicate that primary crack tip plastic deformation (in virgin material) is more effective for crack extension than secondary plastic deformation in an existing plastic zone. This conclusion is significant for cycle‐by‐cycle crack growth prediction models for variable‐amplitude loading.