Effect of Strain Rate and Temperature on the Tensile Flow Behavior and Microstructure Evolution in Fe-0.3 Pct C-CrMoV Grade Steel

Flow behavior and microstructure evolution of 2297 Al-Cu-Li alloy were investigated by isothermal compression tests conducted at the deformation temperature of 300-500°C and strain rates of 0.001-10s-1. The results demonstrate that the characteristics of stress-strain curves depended on the interaction of work hardening and dynamic softening. The true stress increased with the decreasing of temperature and the increasing of the strain rate. At a given deformation condition, the flow curve consisted of three stages: stage I (work hardening stage), stage II (softening stage) and stage III (steady stage). Deformation temperature and strain rate had a great influence on microstructure evolution. 2297 alloy deformed at low temperature (300°C) and high strain rate (10s-1) showed a DRV characteristic. As deformed at high temperature (500°C) and low strain rate (0.001s-1), DRX gradually become the main softening mechanism. The measured flow stress was friction corrected and then employed to develop constitutive equations on the basis of the Arrhenius-type equation by considering the effect of the strain on material constants by a sixth orders polynomials. Flow stress value of 2297 alloy predicted by the proposed constitutive equations shows a good agreement with experimental results, thereby confirming the validity of the developed constitutive relation.

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Hot Deformation Behavior and Microstructure Evolution of GH625 Superalloy Tube during Extrusion Process

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.291-294.640 ◽

2011 ◽

Vol 291-294 ◽

pp. 640-644

Author(s):

Qing Miao Guo ◽

De Fu Li ◽

Sheng Li Guo ◽

Guo Ling Xie

Keyword(s):

Strain Rate ◽

Microstructure Evolution ◽

Hot Deformation ◽

Deformation Behavior ◽

Deformation Temperature ◽

Flow Behavior ◽

Outer Wall ◽

Extrusion Process ◽

Compression Tests ◽

Hot Deformation Behavior

Flow behavior and microstructures of GH625 superalloy were investigated by hot compression tests. Then the GH625 superalloy tube was hot extruded according to the hot deformation behavior, and the microstructures of different position of extruded tube was also analyzed. The results show that the actual deformation temperature of the specimen deformed at a strain rate of 10.0s-1 is higher than the preset temperature, resulting in a deformation thermal effect. Thus, the microstructure evolution of GH625 superalloy is controlled both by the strain rate and deformation temperature. It is also found that the GH625 superalloy tube can be successfully fabricated with a stable extrusion speed of 40 mm·s-1, extrusion ratio of 4.1 and preheating temperature of 1200°C. The microstructure of extruded tube was obviously fined due to the occurrence of dynamic recrystallization(DRX). Different degrees of DRX were observed in outer wall, center and inner wall of the tube, which is similar to that in the head, middle and tail of the tube. An extruded tube containing fully DRX grains can be obtained by cutting the head and tail of the tube, and machining a small amount of the inner wall.

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A Study on the Flow Behavior of 42CrMo Steel under Hot Compression by Thermal Physical Simulations

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.108-111.494 ◽

2010 ◽

Vol 108-111 ◽

pp. 494-499

Author(s):

Ying Tong ◽

Guo Zheng Quan ◽

Gang Luo ◽

Jie Zhou

Keyword(s):

Strain Rate ◽

Flow Behavior ◽

Rate Sensitivity ◽

Strain Hardening Exponent ◽

Forming Process ◽

Material Parameters ◽

Basic Model ◽

42Crmo Steel ◽

Plastic Forming ◽

Physical Simulations

This work was focused on the compressive deformation behavior of 42CrMo steel at temperatures from 1123K to 1348K and strain rates from 0.01s-1 to 10s-1 on a Gleeble-1500 thermo-simulation machine. The true stress-strain curves tested exhibit peak stresses at small strains, after them the flow stresses decrease monotonically until high strains, showing a dynamic flow softening. And the stress level decreases with increasing deformation temperature and decreasing strain rate. The values of strain hardening exponent n, and the strain rate sensitivity exponent m were calculated the method of multiple linear regression, the results show that the two material parameters are not constants, but changes with temperature and strain rate. Then the two variable material parameters were introduced into Fields-Backofen equation amended. Thus the constitutive mechanical discription of 42CrMo steel which can accurately describe the relationships among flow stress, temperature, strain rate, strain offers the basic model for plastic forming process simulation.

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Application of the Strain Compensation Model and Processing Maps for Description of Hot Deformation Behavior of Metastable β Titanium Alloy

Materials ◽

10.3390/ma14082021 ◽

2021 ◽

Vol 14 (8) ◽

pp. 2021

Author(s):

Oleksandr Lypchanskyi ◽

Tomasz Śleboda ◽

Aneta Łukaszek-Sołek ◽

Krystian Zyguła ◽

Marek Wojtaszek

Keyword(s):

Titanium Alloy ◽

Strain Rate ◽

Flow Behavior ◽

Microstructural Analysis ◽

Calculated Data ◽

Processing Temperature ◽

Processing Maps ◽

Compression Tests ◽

Strain And Strain Rate ◽

Average Absolute Relative Error

The flow behavior of metastable β titanium alloy was investigated basing on isothermal hot compression tests performed on Gleeble 3800 thermomechanical simulator at near and above β transus temperatures. The flow stress curves were obtained for deformation temperature range of 800–1100 °C and strain rate range of 0.01–100 s−1. The strain compensated constitutive model was developed using the Arrhenius-type equation. The high correlation coefficient (R) as well as low average absolute relative error (AARE) between the experimental and the calculated data confirmed a high accuracy of the developed model. The dynamic material modeling in combination with the Prasad stability criterion made it possible to generate processing maps for the investigated processing temperature, strain and strain rate ranges. The high material flow stability under investigated deformation conditions was revealed. The microstructural analysis provided additional information regarding the flow behavior and predominant deformation mechanism. It was found that dynamic recovery (DRV) was the main mechanism operating during the deformation of the investigated β titanium alloy.

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Constitutive Modeling for Elevated Temperature Flow Behavior of ZHMn34-2-2-1 Manganese Brass

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.872.30 ◽

2017 ◽

Vol 872 ◽

pp. 30-37

Author(s):

Meng Han Wang ◽

Kang Wei ◽

Xiao Juan Li

Keyword(s):

Constitutive Model ◽

Strain Rate ◽

Flow Behavior ◽

Peak Stress ◽

Strain Rates ◽

Hollomon Parameter ◽

Prediction Ability ◽

Absolute Relative Error ◽

Deformation Behaviors ◽

State Stress

The hot compressive deformation behaviors of ZHMn34-2-2-1 manganese brass are investigated on Thermecmastor-Z thermal simulator over wide processing domain of temperatures (923K-1073K) and strain rates (0.01s-1-10s-1). The true stress-strain curves exhibit a single peak stress, after which the stress monotonously decreases until a steady state stress occurs, indicating a typical dynamic recrystallization. A revised constitutive model coupling flow stress with strain, strain rate and deformation temperature is established with the material constants expressed by polynomial fitting of strain. Moreover, better prediction ability of the constitutive model is achieved by implementation of a simple approach for modified the Zener-Hollomon parameter considering the compensation of strain rate and temperature increment. By comparing the predicted and experimented values, the correlation coefficient and mean absolute relative error are 0.997 and 2.363%, respectively. The quantitative statistical results indicate that the proposed constitutive model can precisely characterize the hot deformation behavior of ZHMn34-2-2-1 manganese brass.

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Comparison of flow behavior of as-cast and hot rolled Al-B4C composites by constant and differential strain rate tests

Advanced Composite Materials ◽

10.1080/09243046.2016.1202393 ◽

2016 ◽

Vol 26 (1) ◽

pp. 65-78 ◽

Cited By ~ 1

Author(s):

S. Gangolu ◽

A.G. Rao ◽

B.P. Kashyap ◽

N. Prabhu ◽

V.P. Deshmukh

Keyword(s):

Strain Rate ◽

Flow Behavior ◽

Hot Rolled

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High-Temperature Mechanical Properties and Constitutive Modelling of Ti6Al4V Sheets

Materials Science Forum ◽

10.4028/www.scientific.net/msf.879.2020 ◽

2016 ◽

Vol 879 ◽

pp. 2020-2025 ◽

Cited By ~ 1

Author(s):

Beatrice Valoppi ◽

Stefania Bruschi ◽

Andrea Ghiotti

Keyword(s):

Elevated Temperature ◽

Strain Rate ◽

Flow Behavior ◽

Hot Stamping ◽

Tensile Tests ◽

Testing Temperature ◽

Constitutive Modelling ◽

Arrhenius Model ◽

High Temperature Mechanical Properties ◽

Material Texture

In this paper, tensile tests were performed at elevated temperature and strain rate in order to investigate the plastic flow behavior, anisotropic characteristics and microstructural evolution of Ti6Al4V sheets under testing conditions similar to the ones experienced during hot stamping operations. It is shown that the Ti6Al4V anisotropic characteristics under the investigated forming conditions, different from the ones of the superplastic regime, are influenced by the variation of the material texture as a function of the testing temperature. The Ti6Al4V flow stress behavior was analyzed as a function of the deformation temperature and strain rate. Afterwards, the Arrhenius constitutive model was proposed to predict the flow behavior of Ti6Al4V sheets at elevated temperature and strain rate. The statistical analysis of its predictive capabilities suggests that the Arrhenius model guarantees a good accuracy in reproducing the flow behavior of Ti6Al4V sheets.

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An Experimental Study on Dynamic Constitutive Relationship of 7075-T651 Aluminum Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.816-817.84 ◽

2013 ◽

Vol 816-817 ◽

pp. 84-89

Author(s):

Yong Gang Kang ◽

Yuan Yang ◽

Jie Huang ◽

Jing Hang Zhu

Keyword(s):

Aluminum Alloy ◽

Constitutive Equation ◽

Strain Rate ◽

Split Hopkinson Pressure Bar ◽

Flow Behavior ◽

Constitutive Relationship ◽

Hopkinson Pressure Bar ◽

Experiment Data ◽

Static Compression ◽

Quasi Static Compression

7075-T651 aluminum alloy are widely used in aeronautical applications such as wing panels, but there is no corresponding constitutive model for it now. In this paper, the flow behavior of 7050-T651 aluminum alloy was investigated by Split Hopkinson Pressure Bar (SHPB) and quasi-static compression experiment system. The strain hardening parameters were obtained by quasi-static compression experiment data, and the strain rate hardening parameters at various strain rates (1000-3000s-1) and room temperature, and the thermal softening parameter at various temperatures (20-300°C) where strain rate is 3000s-1 were obtained by SHPB experiment data. Then the constitutive equation of 7075-T651 aluminum alloy is obtained based on Johnson-Cook constitutive equation model.

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