Constitutive Equation Development for Large Strain Rate Deformation Processing of 2205 Duplex Stainless Steels

2011 ◽  
Vol 695 ◽  
pp. 381-384
Author(s):  
Zhi Yu Chen ◽  
De Ning Zou ◽  
Huan Liu ◽  
Hong Bo Wang

Elevated compression tests were conducted on 2205 duplex stainless steel using a Gleeble 3800 thermal simulator under constant strain rates ranging from 0.1 s−1 to 50 s−1 and at deformation temperatures ranging from 900°C to 1200°C for the sample. All tests were performed at a total true strain of 0.9. The elevated temperature deformation behavior of the 2205 duplex stainless steel was characterized based on an analysis of the stress–strain curves. A set of constitutive equations for 2205 duplex stainless steel was proposed by employing hyperbolic sine function. The equations revealed the dependence of flow stress on strain, strain rate and temperature. In order to evaluate the accuracy of the constitutive equations, the mean errors of flow stress between the experimental data and predicted results were calculated. The results showed that there was a good agreement between the prediction and experimental values.

2012 ◽  
Vol 538-541 ◽  
pp. 1605-1610 ◽  
Author(s):  
Ji Xiang Zhang ◽  
Zheng Jun Li ◽  
Guo Yin An ◽  
Zhi Xiang Wang

The flow behavior of 2205 duplex stainless steel for ship sheet in the strain rate ranging from 0.001 s-1 to 0.1s-1 and temperature ranging from 473K to 1073 K is studied on AG-10TA universal material testing machine. The results show that the 2205 duplex stainless steel is a strain rate sensitive material, and the flow stress increases with the increase of strain rate and decreases with the increase of temperature. The average elongation of the 2205 duplex stainless steel is above 25% with the temperature ranging from 473K-873K, and the elongation is above 47% at 1073K; At last, the flow stress constitutive equation is established based on the Browman model, which describes the flow stress behavior of 2205 duplex stainless steel in the temperature ranging from 473K-873K. The curves predicted by the constitutive equation agreement with the experiment data well.


2014 ◽  
Vol 933 ◽  
pp. 27-31
Author(s):  
Yin Hui Yang

The effect of deformation temperature on microstructure, flow stress and corrosion resistance of 2205 duplex stainless steel was investigated at low strain rate of 0.005 s-1. The flow curve analysis showed that the specimen was mainly characterized with dynamic recovery (DRV) at 850 °C, and the characteristic of dynamic recrystallization (DRX) was enhanced with deformation temperature increasing to 950 and 1050 °C, then flow curves presented steady state with characteristic of DRV at 1150 and 1250 °C. Microstructure analysis exhibited the austenite DRX at deformation temperatures of 1050 and 1150 °C. The specimens deformed at temperatures ranging from 850 to 1250 °C and strain rate of 0.005 s-1presented active-transpassive behavior, indicating faster corrosion rate compared with the as-received, which can be attributed to more ferrite (δ) and austenite (γ) grain boundaries or δ/γ phase boundaries formation.


2012 ◽  
Vol 581-582 ◽  
pp. 1054-1057
Author(s):  
Yin Hui Yang ◽  
Shao Hong Li

Under strain rate of 0.5s-1, the effect of deformation temperature on flow stress, microstructure and corrosion resistance of 2205 duplex stainless steel (DSS) was investigated. The dynamic recrystallization (DRX) of austenite phase was enhanced with the deformation temperature increasing from 850°C to 1050°C, meanwhile, the leading deformation mechanism changed from work hardening to DRX. When the deformation temperature was further increased to 1250°C, the dynamic recovery (DRV) of ferrite phase played a leading role. The specimen after deformation at 1050°C exhibited better DRX behavior, which leads to more γ/γ grain boundaries and δ/γ boundaries formation, increasing the occurrence of pitting corrosion, and it presented best corrosion resistance at 950°C.


2017 ◽  
Vol 36 (7) ◽  
pp. 701-710
Author(s):  
Jun Cai ◽  
Kuaishe Wang ◽  
Xiaolu Zhang ◽  
Wen Wang

AbstractHigh temperature deformation behavior of BFe10-1-2 cupronickel alloy was investigated by means of isothermal compression tests in the temperature range of 1,023~1,273 K and strain rate range of 0.001~10 s–1. Based on orthogonal experiment and variance analysis, the significance of the effects of strain, strain rate and deformation temperature on the flow stress was evaluated. Thereafter, a constitutive equation was developed on the basis of the orthogonal analysis conclusions. Subsequently, standard statistical parameters were introduced to verify the validity of developed constitutive equation. The results indicated that the predicted flow stress values from the constitutive equation could track the experimental data of BFe10-1-2 cupronickel alloy under most deformation conditions.


2014 ◽  
Vol 1058 ◽  
pp. 165-169 ◽  
Author(s):  
Shi Ming Hao ◽  
Jing Pei Xie

The hot deformation behaviors of 30%SiCp/2024 aluminum alloy composites was studied by hot compression tests using Gleeble-1500 thermomechanical simulator at temperatures ranging from 350-500°C under strain rates of 0.01-10 s-1. The true stress-true strain curves were obtained in the tests. Constitutive equation and processing map were established. The results show that the flow stress decreases with the increase of deformation temperature at a constant strain rate, and increases with the increase of strain rate at constant temperature, indicating that composite is a positive strain rate sensitive material. The flow stress behavior of composite during hot compression deformation can be represented by a Zener-Hollomon parameter in the hyperbolic sine form. Its activation energy for hot deformation Q is 183.251 kJ/mol. The optimum hot working conditions for this material are suggested.


2019 ◽  
Vol 51 (1) ◽  
pp. 467-481
Author(s):  
Suwaree Chankitmunkong ◽  
Dmitry G. Eskin ◽  
Chaowalit Limmaneevichitr

Abstract Aluminum piston alloys of the AA4032 type are produced by direct-chill (DC) casting and subsequent forging; therefore, it is important to understand their thermomechanical behavior. In recent years, it was shown that additions of Cu and Er could improve mechanical properties of these alloys at room and high temperatures. In this work, we studied the constitutive behavior of AA4032-type alloys with and without Cu and Er additions. The experimental true stress–true strain curves were obtained by compression tests under various temperatures [683 K to 723 K (410 °C to 450 °C)] and strain rates (0.01 to 10 s−1) to determine constitutive parameters [strain-rate sensitivity, activation energy, and Zener–Hollomon (Z) parameter] for the hot deformation behavior of AA4032-type piston alloys with and without additions of Cu and Er. The flow stress decreased with increasing deformation temperature and decreasing strain rate. The results also showed that increasing the Cu content increased the flow stress over the applied range of deformation conditions due to solid-solution strengthening and the formation of primary Si particles, which led to an increase in the activation energy during hot deformation. Moreover, the main microstructural damage in the AA4032 alloy with 3.5 pct Cu was predominantly due to the cracking of primary Si particles. Additions of 0.4 pct Er and 3.5 pct Cu lower the activation energy of deformation, Q, as compared to the base alloy and the alloy with 3.5 pct Cu. The microstructures in the deformed specimens consisted of subgrains, recrystallized grains, and fine eutectic phases. The alloys containing Er demonstrated more polygonized grains at a low strain rate than the alloys without Er, indicating that Er hindered recrystallization development. The peak stress of the AA4032 alloy with 3.5 pct Cu alloy was higher than for the base AA4032 alloy and for the AA4032 alloy with 3.5 pct Cu and 0.4 pct Er additions, which was attributed to the prevalence of the work-hardening mechanism over the softening mechanism.


2013 ◽  
Vol 592-593 ◽  
pp. 724-727
Author(s):  
Andrzej Nowotnik ◽  
Paweł Rokicki ◽  
Paweł Pędrak ◽  
Slawomir Kotowski ◽  
Jan Sieniawski ◽  
...  

Variations of a true stress vs. true strain illustrate behaviour of materials during plastic deformation. Stress-strain relationship is generally evaluated by a torsion, compression and tensile tests. Results of these tests provide crucial information pertaining to the stress values which are necessary to run deformation process at specified temperature and cooling rate. Uniaxial compression tests at temperatures below the γ solvus were conducted on nickel based superalloy CMSX-4, to study the effect of temperature and strain rate on its flow stress. On the basis of received flow stress values activation energy of a high-temperature deformation process was estimated. Mathematical dependences (σpl -T i σpl - ἐ) and compression data were used to determine material constants. These constants allow to derive a formula that describes the relationship between strain rate, deformation temperature and true stress.


2013 ◽  
Vol 17 (5) ◽  
pp. 1523-1528
Author(s):  
Bao-Hua Jia ◽  
Wei-Dong Song ◽  
Hui-Ping Tang ◽  
Jian-Guo Ning

Isothermal compression tests of TC18 titanium alloy at the deformation temperatures ranging from 25?C to 800?C and strain rate ranging from 10-4 to 10-2 s-1 were conducted by using a WDW-300 electronic universal testing machine. The hot deformation behavior of TC18 was characterized based on an analysis of the true stress-true strain curves of TC18 titanium alloy. The curves show that the flow stress increases with increasing the strain rate and decreases with increasing the temperature, and the strain rate play an important role in the flow stress when increasing the temperatures. By taking the effect of strain into account, an improved constitutive relationship was proposed based on the Arrhenius equation. By comparison with the experimental results, the model prediction agreed well with the experimental data, which demonstrated the established constitutive relationship was reliable and can be used to predict the hot deformation behavior of TC18 titanium alloy.


2015 ◽  
Vol 62 (3) ◽  
pp. 163-171 ◽  
Author(s):  
Yinhui Yang ◽  
Biao Yan

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−1, 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−1, the worst corrosion resistance behavior from the potentiodynamic polarization test results after deformation at 0.005 s−1 was attributed to more austenite (γ) and ferrite (δ) grain boundaries or δ/γ phase interface formation due to the better effect of γ dynamic recrystallization (DRX) or δ dynamic recovery (DRV). Increasing strain rate to 5 s−1 lowered the corrosion resistance, due to the increase in dislocation density. At the low strain rate of 0.005 s−1, the susceptibility to intergranular corrosion (IGC) was comparatively high after deformation at 1050 and 1150°C with more γ/γ grains and δ/γ phase boundary formation, which was lowered with the strain rate increase to 0.5 s−1, due to suppressing effect of γ DRX. Originality/value – The paper provides the scientific basis for the practical application of hot working of 2205 duplex stainless steel.


2014 ◽  
Vol 922 ◽  
pp. 807-812 ◽  
Author(s):  
Robert Werner ◽  
Emanuel Schwaighofer ◽  
Martin Schloffer ◽  
Helmut Clemens ◽  
Janny Lindemann ◽  
...  

In the present study the high-temperature deformation behavior of a caste and subsequently HIPed β-solidifying γ-TiAl-based alloy with a nominal composition of Ti-43.5Al-4Nb-1Mo-0.1B (in at. %), termed TNM alloy, is investigated. At room temperature this alloy consists of ordered γ-TiAl, α2-Ti3Al and βo-TiAl phases. By increasing the temperature, α2and βodisorder to α and β, respectively. In order to get a better understanding of dynamic recovery and recrystallization processes during thermomechanical processing, isothermal compression tests on TNM specimens are carried out on a Gleeble®3500 simulator. These tests are conducted at temperatures ranging from 1100 °C to 1250 °C (in the α/α2+β/βo+γ phase field region) applying strain rates in the range of 0.005 s-1to 0.5 s-1up to a true strain of 0.9. The evolution of microstructure along with the dynamically recrystallized grain size during hot deformation is examined by scanning electron microscopy (SEM). The flow softening behavior after reaching the peak stress in the true stress-true strain curve is attributed to dynamic recrystallization. By using the Zener-Hollomon parameter as a temperature-compensated strain rate the dependence of flow stress on temperature and strain rate is shown to follow a hyperbolic-sine Arrhenius-type relationship.


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