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The characteristics of fatigue under isothermal and thermo‐mechanical load in Cr–Ni–Mo cast hot work die steel
Author(s) -
FANG J. R.,
JIANG Q. C.,
GUAN Q. F.,
WANG S. Q.
Publication year - 2002
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 - 10.1046/j.1460-2695.2002.00513.x
Subject(s) - materials science , isothermal process , creep , fracture (geology) , intergranular corrosion , ultimate tensile strength , work (physics) , metallurgy , hot work , composite material , stress (linguistics) , structural engineering , microstructure , tool steel , thermodynamics , engineering , mechanical engineering , linguistics , physics , philosophy
High temperature isothermal fatigue (IF) and in‐phase thermo‐mechanical fatigue (TMF) tests in load control were carried out in cast hot work die steel. At the same load amplitude, the fatigue lives obtained in the in‐phase TMF tests are lower than those obtained in the isothermal tests. Observations of fracture surface and the response of stress–strain reveal that cyclic creep in the tensile direction occurs and the intergranular cracks dominate in TMF tests, whereas cyclic creep in the compressive direction occurs and the path of the crack growth is mainly transgranular in IF tests. A model of life prediction, based on the Chaboche law, was discussed. Damage coefficients that are functions of the maximum temperature and the variation of temperature are introduced in the model so as to evaluate TMF lives in load control. With this method, the lifetime prediction gives results corresponding well to experimental data.