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THE EFFECT OF CYCLE WAVESHAPE ON THE LOW CYCLE FATIGUE BEHAVIOUR OF 20%Cr–25%Ni–Nb STAINLESS STEEL AT 650°C
Author(s) -
GLADWIN D.,
MILLER D. A.
Publication year - 1982
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.1460-2695.1982.tb01236.x
Subject(s) - materials science , creep , low cycle fatigue , ductility (earth science) , compression (physics) , metallurgy , tension (geology) , ultimate tensile strength , metallography , strain (injury) , strain rate , structural engineering , composite material , microstructure , engineering , medicine
— Low cycle fatigue tests at 650°C on 20% Cr–25% Ni–Nb stainless steel have been carried out under conditions of equal tension/compression ramp rates (10 −3 s −1 ) and slow tension–fast compression ramp rates (10 −6 s −1 /10 −3 s −1 ). It was found that the latter cycle significantly reduced endurance. Detailed metallography revealed that life reduction is due to the accumulation of creep damage during the slow tensile ramp. It is proposed that at high strain ranges, failure is creep dominated and this changes to a creep‐fatigue interaction failure mechanism at low strain ranges. Predictive models have been developed based on cavity growth mechanisms and ductility exhaustion. Both techniques provide an accurate life prediction and only limited data are required to use them.