Hot deformation behavior and microstructural evolution of 2205 duplex stainless steel

Abstract

The equiaxed compression test was used to study the microstructure evolution and the dynamic recrystallization behavior of 2205 duplex stainless steel during hot deformation under 850-1100°C with strain rates of 0.01 s −1 , 0.1 s −1 , 1 s −1 and 10 s −1 . The calculated values of thermal deformation activation energy Q and stress index n were 351.58 kJ mol −1 and 3.8543, respectively. On this basis, the Arrhenius type constitutive equation was successfully established, the microstructure of the sample was studied by electron backscatter diffraction (EBSD), and the changes of the ferrite and austenite phase under different deformation parameters were analyzed. It was seen from the phase boundary and grain boundary diagrams that, at the same temperature, as the deformation rate increased, the austenite phase content slowly decreased, while the ferrite phase content increased. The deformation amount of the two phases under the same strain at different temperatures and strain rates were respectively obtained from the grain orientation scatter diagram and the changes of recrystallization, deformation and substructure under different deformation parameters were obtained from the recrystallization diagram.

Investigations on the Johnson-Cook Constitutive and Damage-Fracture Model Parameters of a Q345C Steel

“…The reason for blue brittleness is the deformation aging of carbon and nitrogen interstitial atoms. When deformed within the temperature range of 150-350 • C, dislocations that have already activated are quickly anchored by diffusible carbon and nitrogen atoms, forming a Coriolis gas mass [49,50]. In order for further deformation, new dislocations must be activated, resulting in an increase in dislocation density of the steel at given strain levels, leading to an increase in strength and a decrease in toughness.…”

Determination of the impact of strain rate on dynamic recrystallization of hot-deformed 2205 duplex stainless steel

“…The ferrite phase is soft with high stacking fault energy and low thermal strength, which could result in clumping when subjected to hot deformation. On the other hand, austenite possesses hard characteristics with high thermal strength and low stacking fault energy that yields a suppressed dynamic recovery of dislocated gains during hot deformation [11].…”

“…This prediction can be made by physical evaluation (microstructural) or calculation (analytical and constitutive models). Previous research has deeply studied critical strain, critical stress and peak stress of the as-rolled hot-or cold-deformed 2205 DSS [11]. From the previous investigation, it was established that DRX thermal deformation parameters such as temperature, strain rate, and strain influence the nucleation of twin grains.…”

A Comparative Study of Three Constitutive Models concerning Thermo-Mechanical Behavior of Q345 Steel during Hot Deformation

“…It can guide the finite element simulation, determine the ideal parameters of thermal processing, and assist to guide the manufacturing process. At present, the constitutive models including Johnson-Cook [7] and Arrhenius [8,9] often describe the thermal deformation characteristics of materials. To be more specific, the JC model is extensively used to explain the thermal deformation behavior of alloys on account of the simplicity of its multiplicative form, while the Arrhenius type formula proposed by Sellars and McTegart expresses the flow stress according to the law of hyperbolic sine, which has been improved many times and can be applied to the high temperature rheological behavior of various alloys.…”