Effects of solutes and temperature on high-temperature deformation and subsequent recovery in hot-rolled low alloy steels

The high temperature deformation behavior, kinetics of recovery and onset of recrystallization in ternary Fe-0.1%C-X (X = Mn, Si or Al) alloys have been investigated. The alloys were hot-deformed to a strain of 0.25 at various temperatures from 850 °C to 1100 °C, at a strain rate of 1 s−1. The effect of solutes and temperature on the flow stress was examined. In addition, stress-relaxation experiments were performed to quantify the restoration behaviour. The stress relaxation curves can be divided into three regimes: recovery, recrystallization and grain growth. A widely used recovery model was adopted to capture recovery kinetics. Effects of dislocations, solutes and temperature were considered through an effective activation volume term. Dislocations and solutes tend to decrease the activation volume while temperature will have the opposite effect. The onset of recrystallization was delayed with increasing alloying solutes and lowering temperatures. It is concluded that the solutes effects on work-hardening decreased from Al, Si to Mn and high temperatures can facilitate dynamic recovery during deformation; the same effects of solutes and temperature were observed for subsequent recovery.