Effect of high temperature compression deformation strain rate on the microstructure and corrosion behavior of 2205 duplex stainless steel

Abstract

Purpose -The aim of this paper was to investigate the effect of strain rate on microstructure and corrosion behavior of 2205 duplex stainless steel, after high-temperature compression tests. Design/methodology/approach -The specimens were prepared using a Gleeble3800 thermo-simulation machine over a range of temperatures from 850 to 1,250°C and strain rates from 0.005 to 5 s Ϫ1 , and the corresponding flow curves and deformation microstructure obtained were further analyzed. To evaluate the effect of strain rate on corrosion behavior, potentiodynamic polarization tests and double-loop electrochemical potentiodynamic reactivation (DL-EPR) were used to characterize the electrochemical performance. Findings -Compared with strain rate of 0.5 s Ϫ1 , the worst corrosion resistance behavior from the potentiodynamic polarization test results after deformation at 0.005 s Ϫ1 was attributed to more austenite (␥) and ferrite (␦) grain boundaries or ␦/␥ phase interface formation due to the better effect of ␥ dynamic recrystallization (DRX) or ␦ dynamic recovery (DRV). Increasing strain rate to 5 s Ϫ1 lowered the corrosion resistance, due to the increase in dislocation density. At the low strain rate of 0.005 s Ϫ1 , the susceptibility to intergranular corrosion (IGC) was comparatively high after deformation at 1050 and 1150°C with more ␥/␥ grains and ␦/␥ phase boundary formation, which was lowered with the strain rate increase to 0.5 s Ϫ1 , due to suppressing effect of ␥ DRX. Originality/value -The paper provides the scientific basis for the practical application of hot working of 2205 duplex stainless steel.