SYNTHESIS OF THE ELASTOVISCOPLASTIC BEHAVIOR AND MODELIZATION OF AN AUSTENITIC STAINLESS-STEEL OVER A LARGE TEMPERATURE-RANGE, UNDER UNIAXIAL AND BIAXIAL LOADINGS .1. BEHAVIOR

The present article shows the diversity of monotonic, cyclic, and viscous mechanical properties of an austenitic 17-12 Mo-SPH stainless steel in the intermediate temperature domain: 20 less-than-or-equal-to T less-than-or-equal-to 700-degrees-C, and for unidirectional or bidirectional loadings, both in and out of phase. The strong interaction phenomena between dislocations and point-defect configurations is clearly shown and can explain the negative strain rate sensitivity observed between 200-degrees and 550-degrees-C. In addition, for nonradial cyclic loadings, a supplementary hardening appears, which is a function of the phase difference between the strain components and results from the activation of secondary slip systems. This new hardening is a strongly decreasing function of the temperature. Above 550-degrees-C, and for long enough time intervals, a fine intergranular precipitation of carbides appears and affects the thermomechanical behavior of this alloy.