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REPRESENTATION OF CYCLIC PROPERTIES OF AUSTENITIC STEELS WITH PLASTICITY‐INDUCED MARTENSITIC TRANSFORMATION
Author(s) -
Kaleta J,
Zie G
Publication year - 1998
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.1460-2695.1998.00086.x
Subject(s) - materials science , austenite , martensite , plasticity , diffusionless transformation , inflection point , hysteresis , metallurgy , phase (matter) , composite material , microstructure , condensed matter physics , mathematics , geometry , physics , quantum mechanics
This study is part of a wider research project on the cyclic properties, energy cumulation and fatigue life of metastable austenitic steels undergoing a martensitic transformation induced by plastic straining. This paper considers the representation of the σ–ε hysteresis loop over a wide range of strain. A novel, power‐function model of cyclic elastic–plastic material behaviour was used. The model allows the occurrence of a cyclic yield point and the characteristic inflection point of the CSS curve, which separates the single‐phase (austenite) region from the two‐phase (austenite + martensite) one. The plastic strain corresponding to the inflection point is assumed to be a material constant and is termed the martensitic transformation cyclic limit ε1 . The generalization of the model made possible the representation of cyclic softening of the two‐phase material. In addition, the study chose a measurement technique that assisted the estimation of the cyclic plastic strain (ε1 ) inducing the martensitic transformation. The crossed magnetomechanical (Villari) effect was shown to be applicable in detecting the nucleation and estimating the increase of the α′‐martensite content. The identification was performed making use of experimental results obtained from an AISI 304 high nickel content steel. The tests were performed under both increasing and constant plastic strain amplitude. The measured quantities were: total strain εt elastic strain εe , plastic strain εp , stress σ and hysteresis loop area ΔW. The results justify the assumed model.