Quantitative description of the flow-stress dependence of aluminum alloys at the stage of steady flow upon hot deformation on the Zener–Hollomon parameter

Abstract

The deformation behavior of a 1981 aluminum alloy has been studied using a complex for simulating thermomechanical processes in the temperature range of 200–400°C at a deformation rate in the range of 0.001–10 s–1. The models of the relationships between the flow stress, temperature, and deformation rate have been constructed using a power-law dependence, exponential dependence, and hyperbolic-sine function on the Zener–Hollomon parameter (Z). In the calculations according to the power-law and exponential equations, discrepancies between the calculated and experimental values of the Zener–Hollomon parameter have been revealed at low and high values. These discrepancies are caused by the fact that the experimentally obtained dependences of the flow stress on the Z parameter over the entire range of its change with a single magnitude of the effective activation energy of the plastic deformation consist of two linear parts that correspond to the hot and warm deformation and have different magnitudes of the effective activation energy of plastic deformation with a lower value of the activation energy for hot deformation.