PSI - Issue 41

Abdelmoumene Guedri et al. / Procedia Structural Integrity 41 (2022) 564–575 Abdelmoumene Guedri et al. / Structural Integrity Procedia 00 (2022) 000–000

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Fig. 2. Heat treatment cycle aimed at precipitation before deformation.

Fig. 3. Hot tensile specimen.

3. Experimental results 3.1. Peak stress

The evolution of the maximum stress  p as a function of the temperature for different strain rates are shown in Figure 4. It is noted that the maximum stress has a specific behavior in the two-phase domain, this being explained by a synergistic effect between the volume fraction of the ferritic phase more ductile than the austenitic phase and a more or less significant presence of precipitates. The maximum stress increases between temperatures 750 and 800°C, for all strain rates, then decreases in the austenitic range. In the two-phase domain, the stress  p decreases at the temperature of 850°C. This trend is explained by the presence of a substantially homogeneous predominantly austenitic structure and a lower presence of precipitates. Between 850 and 900°C, the stress increases and then decreases for higher temperatures. Peak stress  p is detected around 900°C (presence of a single harder austenitic phase).