Inelastic behavior of modified 9Cr-1 Mo steel under basic loading conditions at elevated temperature and evaluation of two unified constitutive models

The purposes of this paper are to elucidate fundamental material properties of modified 9Cr-1 Mo steel as a candidate material for next-generation fast breeder reactors and to obtain information for the formulation of a practical unified constitutive model. For these purposes, monotonous tension, uniaxial symmetric cycles, uniaxial symmetric cycles with hold time, creep, stress control uniaxial symmetric cycles, cyclic relaxation and circular cyclic loading tests are performed. Then these results are simulated by two unified constitutive models, i.e. the Chaboche model and Bodner-Partom model. The results of simulation show that the Chaboche model can describe all the experimental results with relatively high accuracy, and that the identification of material constants of the model is easy. The Bodner-Partom model can similarly describe the results, but the determination of material constants is difficult. (author)