Simulation of the Rheological Behavior and Dynamic Recrystallization of the Heterogenized V95 (7075) Alloy

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In this paper, a structural hierarchical viscoplastic model is identified. The model describes the flow stress and the evolution of the microstructure of the heterogenized V95 alloy (the Russian analogue of the 7075 alloy) at a temperature of 400°C in strain rates ranging between 0.01 and 5 s−1. The model describes alloy hardening through increasing dislocation density and softening due to dynamic recovery and recrystallization. The model parameters responsible for dynamic recrystallization are identified by electron backscattered diffraction data. The identification results testify that, at a time-varying strain rate, the model determines the value of flow stress and the amount of dynamic recrystallization with an average relative deviation of 4.2 and 7.6%, respectively. The model is used to obtain the strain rate and strain dependences of the amount of dynamic recrystallization, as well as to plot flow stress curves for strain rates ranging between 0.01 and 5 s−1. The simulation results have allowed us to establish that, with the same accumulated strain level, an increase in the strain rate of the V95 alloy at a temperature of 400°C leads to an increase in the portion of dynamically recrystallized grains. Dynamic recrystallization has a noticeable effect on the shape of the flow stress curve at strain rates exceeding 0.5 s−1, when a pronounced peak appears in the flow stress curves.