On the Macroscopic Flow Behavior of the Phases Present in Ti-24Al-llNb

1988 ◽  
Vol 133 ◽  
Author(s):  
S. J. Giths ◽  
D. A. Koss
Keyword(s):  
High Temperature ◽  
Strain Rate ◽  
Deformation Behavior ◽  
Flow Behavior ◽  
Tensile Tests ◽  
High Temperature Creep ◽  
Two Phase ◽  
Strain And Strain Rate ◽  
Beta Alloy ◽  
Strain Rate Hardening

ABSTRACTThe deformation behavior of two alloys whose compositions (Ti-25Al-9Nb and Ti-11Al-23Nb in at.%) correspond to alpha-two and beta phases in the Ti-24Al-11Nb alloy has been investigated. Results from both compression and tensile tests over a range of temperatures from 27° to 650°C indicate that the yield stress as well as the strain and strain-rate hardening characteristics of the Ti-24-11 alloy are controlled by the Ti3Al-base alpha-two phase. In contrast to the Alpha-two alloy, the Beta alloy has a flow stress which is very sensitive to temperature and strain rate at 650°C, suggesting the onset of high temperature creep processes.

High Temperature Deformation Mechanism Maps of NiAl

2004 ◽  
Vol 449-452 ◽  
pp. 57-60
Author(s):  
I.G. Lee ◽  
A.K. Ghosh
Keyword(s):  
High Temperature ◽  
Strain Rate ◽  
Deformation Mechanism ◽  
Calculation Method ◽  
Deformation Behavior ◽  
Tensile Tests ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Grain Sizes ◽  
Temperature Strain

In order to analyze high temperature deformation behavior of NiAl alloys, deformation maps were constructed for stoichiometric NiAl materials with grain sizes of 4 and 200 µm. Relevant constitute equations and calculation method will be described in this paper. These maps are particularly useful in identifying the location of testing domains, such as creep and tensile tests, in relation to the stress-temperature-strain rate domains experienced by NiAl.

High-Strain-Rate Superplastic Flow Mechanism in ZrO2-30vol% Spinel Two-Phase Composite

2010 ◽  
Vol 433 ◽  
pp. 333-338 ◽  
Author(s):  
Koji Morita ◽  
Keijiro Hiraga ◽  
Byung Nam Kim ◽  
Hidehiro Yoshida
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Flow Behavior ◽  
Recovery Process ◽  
Lattice Diffusion ◽  
Two Phase ◽  
Data Set ◽  
Strain And Strain Rate ◽  
Accommodation Process

High-strain-rate superplasticity (HSRS) can be attained in tetragonal ZrO2-30vol% MgAl2O4 spinel composite. In order to examine the flow behavior of the two-phase composite, the standard rule of the mixture model was employed. The strain rate of the composite can be explained by the isostrain model that is predicted from the data set of Al2O3 doped ZrO2 and spinel polycrystals. For the isostrain model, since the strain and strain rate are the same for ZrO2 and spinel phases, the harder ZrO2 phase carries more of the stress in the composite. In order to preserve homogeneous deformation and material continuity, a concomitant accommodation process within the harder ZrO2 grains is also necessary. For HSRS in the ZrO2-spinel composite, therefore, the rate of deformation may be controlled by the slower dislocation recovery process limited by the lattice diffusion within harder ZrO2 grains rather than within spinel grains.

Hot Deformation Behavior of the 30%Mo/Cu-Al2O3 Composite Prepared by Vacuum Hot-Pressed Sintering

2011 ◽  
Vol 117-119 ◽  
pp. 893-896
Author(s):  
Yong Liu ◽  
Yong Wei Sun ◽  
Bao Hong Tian ◽  
Jiang Feng ◽  
Yi Zhang
Keyword(s):  
High Temperature ◽  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Flow Behavior ◽  
Peak Stress ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Compression Tests ◽  
Hot Deformation Behavior

Hot deformation behavior of the 30%Mo/Cu-Al2O3 composite was investigated by hot compression tests on Gleeble-1500D thermal simulator in the temperature ranges of 450~750°C and the strain rate ranges of 0.01~5s-1, as the total strain is 0.7. The results show that the peak stress increases with the decreased deformation temperature or the increased strain rate. Based on the true stress-strain curves, the established constitutive equation represents the high-temperature flow behavior of the composite, and the calculated flow stresses are in good agreement with the high- temperature deformation experimental results.

scholarly journals HIGH-TEMPERATURE DEFORMATION BEHAVIOR AND HOT-PROCESSING MAP OF 25CrMo4 AXLE STEEL BASED ON FRICTION CORRECTION

2021 ◽  
Vol 55 (6) ◽  
Author(s):  
Keran Liu ◽  
Yuanming Huo ◽  
Tao He ◽  
Cunlong Huo ◽  
Changyuan Jia ◽  
...  
Keyword(s):  
High Temperature ◽  
Strain Rate ◽  
Process Parameters ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Deformation Temperature ◽  
Deformation Process ◽  
Flow Behavior ◽  
Temperature Deformation ◽  
Flow Curves

The deformation behavior and microstructure of 25CrMo4 axle steel was systematically investigated by thermal compression deformation. The hot-compression test of a 25CrMo4 axle steel sample was carried out on a Gleeble-3800 thermal mechanical simulation tester. The flow behavior of the alloy was studied at the deformation temperature (900–1200 °C), strain rates (0.01; 0.1; 1.0) s–1 and the maximum deformation of 60 %. The flow curves under different deformation conditions were obtained, and the effects of the deformation temperature and strain rate on the appearance of the flow curves are discussed. The true stress-strain curve obtained by experiment is modified by friction. Based on the corrected experimental data, the activation energy determined by the regression analysis was Q = 311 kJ/mol, and the constitutive model was constructed. The high-temperature flow behavior of the 25CrMo4 axle steel was described by the Zener-Hollomon parameter. The optimum hot-deformation process parameters were determined based on the hot processing maps, followed by the analysis of the microstructure characteristics of the alloys under optimum hot working. The results show that the suitable hot-deformation process parameters of the alloy are as follows: deformation temperature is 1050–1200 °C, and strain rate is 0.01 s–1 to 0.14 s–1.

A Modified Johnson–Cook Constitutive Model and Its Application to High Speed Machining of 7050-T7451 Aluminum Alloy

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Bing Wang ◽  
Zhanqiang Liu ◽  
Qinghua Song ◽  
Yi Wan ◽  
Xiaoping Ren
Keyword(s):  
Aluminum Alloy ◽  
Constitutive Model ◽  
Strain Rate ◽  
Deformation Behavior ◽  
High Speed ◽  
Dynamic Deformation ◽  
Fe Analysis ◽  
High Speed Machining ◽  
Strain And Strain Rate ◽  
Strain Rate Hardening

Constitutive model is the most commonly used method to describe the material deformation behavior during machining process. This paper aims to investigate the material dynamic deformation during high speed machining of 7050-T7451 aluminum alloy with the aid of split Hopkinson pressure bar (SHPB) system and finite element (FE) analysis. First, the quasi static and dynamic compression behaviors of 7050-T7451 aluminum alloy are tested at different loading conditions with a wide range of strain rates (0.001 s, 4000 s, 6000 s, 8000 s, and 12,000 s) and temperatures (room temperature, 100 °C, 200 °C, 300 °C, and 400 °C). The influences of temperature on strain and strain rate hardening effects are revealed based on the flow stress behavior and microstructural alteration of tested specimens. Second, a modified Johnson–Cook (JCM) constitutive model is proposed considering the influence of temperature on strain and strain rate hardening. The prediction accuracies of Johnson–Cook (JC) and JCM constitutive models are compared, which indicates that the predicted flow stresses of JCM model agree better with the experimental results. Then the established JC and JCM models are embedded into FE analysis of orthogonal cutting for 7050-T7451 aluminum alloy. The reliabilities of two material models are evaluated with chip morphology and cutting force as assessment criteria. Finally, the material dynamic deformation behavior during high speed machining and compression test is compared. The research results can help to reveal the dynamic properties of 7050-T7451 aluminum alloy and provide mechanical foundation for FE analysis of high speed machining.

Beta-Forging of Ti6Al4V Titanium Alloy Powders Consolidated by HIP: Plastic Flow and Strain-Rate Relation

2014 ◽  
Vol 783-786 ◽  
pp. 613-618 ◽  
Author(s):  
Claudio Testani ◽  
Antonino Squillace ◽  
Livan Fratini
Keyword(s):  
Titanium Alloy ◽  
High Temperature ◽  
Strain Rate ◽  
Deformation Behavior ◽  
Tensile Tests ◽  
Statistical Correlation ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Small Scale ◽  
Deformation Tests

Ti6Al4V is probably the best known and studied titanium alloy, not only for aerospace applications. Nevertheless the deformation behavior still represents a challenge if any modification in the deformation process is required or introduced. This work deals with deformation behavior description of Ti6Al4V HIPped powders during high temperature deformation tests carried on in the Beta-region. Laboratory compression and tensile tests have been coupled with relaxation tests in order to achieve robust data about strain rate sensibility m-coefficient and activation energy Q. These results have been fitted for the assessment of a more general exponential deformation law. The final result is a “Dorn model” that takes into account and compare all the results from the three different laboratory techniques: compression, tensile and relaxation with a statistical correlation coefficient Rd2=0,78. The deformation tests have been carried out at temperatures ranging from 1173 K up to 1373 K and strain rate from 0,01 s-1 up to about 1 s-1, trying to describe the high temperature complex shape forging operations.The final results has been used and are in use for modeling the forging precursors and dies-shapes to optimize industrial small scale forging tests.

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

Materials ◽  
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.

Deformation Behavior and Constitutive Equation of 42CrMo Steel at High Temperature

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1614
Author(s):  
Hongqiang Liu ◽  
Zhicheng Cheng ◽  
Wei Yu ◽  
Gaotian Wang ◽  
Jie Zhou ◽  
...  
Keyword(s):  
High Temperature ◽  
Flow Stress ◽  
Strain Rate ◽  
Thermal Processing ◽  
Deformation Behavior ◽  
Reduction Process ◽  
Ann Model ◽  
Forming Process ◽  
Temperature Reduction ◽  
42Crmo Steel

High-temperature reduction pretreatment (HTRP) is a process that can significantly improve the core quality of a billet. The existing flow stress data cannot meet the needs of simulation due to lack of high temperature data. To obtain the hot forming process parameters for the high-temperature reduction pretreatment process of 42CrMo steel, a hot compression experiment of 42CrMo steel was conducted on Gleeble-3500 thermal-mechanical at 1200–1350 °C with the rates of deformation 0.001–10 s−1 and the deformation of 60%, and its deformation behavior at elevated temperature was studied. In this study, the effects of flow stress temperature and strain rate on austenite grain were investigated. Moreover, two typical constitutive models were employed to describe the flow stress, namely the Arrhenius constitutive model of strain compensation and back propagation artificial neural network (BP ANN) model. The performance evaluation shows that BP ANN model has high accuracy and stability to predict the curve. The thermal processing maps under strains of 0.1, 0.2, 0.3, and 0.4 were established. Based on the analysis of the thermal processing map, the optimal high reduction process parameter range of 42CrMo is obtained: the temperature range is 1250–1350 °C, and the strain rate range is 0.01–1 s−1.

Numerical Analysis of Plane-Strain Tension Test for Rate-Dependent Solids

1992 ◽  
Vol 59 (3) ◽  
pp. 485-490 ◽  
Author(s):  
P. Tugˇcu
Keyword(s):  
Numerical Analysis ◽  
Strain Rate ◽  
Plane Strain ◽  
Rate Sensitivity ◽  
Tension Test ◽  
Engineering Strain ◽  
Plane Strain Tension ◽  
Rate Dependent ◽  
Strain And Strain Rate ◽  
Strain Rate Hardening

The plane-strain tension test is analyzed numerically for a material with strain and strain-rate hardening characteristics. The effect of the prescribed rate of straining is investigated for an additive logarithmic description of the material strain-rate sensitivity. The dependency to the imposed strain rate so introduced is shown to have a significant effect on several features of the load-elongation curve such as the attainment of the load maximum, the onset of localization, and the overall engineering strain.

High-Temperature Mechanical Properties and Constitutive Modelling of Ti6Al4V Sheets

2016 ◽  
Vol 879 ◽  
pp. 2020-2025 ◽  
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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