scholarly journals A Comparative Study on Arrhenius and Johnson–Cook Constitutive Models for High-Temperature Deformation of Ti2AlNb-Based Alloys

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 123 ◽  
Author(s):  
Zhubin He ◽  
Zhibiao Wang ◽  
Peng Lin
Keyword(s):  
Flow Stress ◽  
Elevated Temperatures ◽  
Constitutive Models ◽  
Superplastic Forming ◽  
Tensile Tests ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Uniaxial Tensile ◽  
Wide Range ◽  
Stress And Deformation

In order to thoroughly understand the quantitative relationships between the flow stress and deformation conditions for Ti2AlNb-based alloys at elevated temperatures, the Arrhenius and Johnson–Cook constitutive models are analyzed and identified on the basis of the uniaxial tensile tests. The Johnson–Cook model is modified so that the referenced temperature range can be randomly adjusted. By experimental verification, the Arrhenius model (including the Backofen model) is suitable for the deformation at relatively low strain-rate deformation, such as the superplastic forming, and the modified J–C model is applicable for the deformation within a wide range of strain rates. For deformation at high temperatures, the constitutive model enables a more precise description of the effect of strain on the flow stress through introducing as train-softening factor exp(sε).

Formability of Ti–29Nb–13Ta–4.6Zr Biomaterial at High Temperatures

2010 ◽  
Vol 443 ◽  
pp. 620-625
Author(s):  
Ming Jen Tan ◽  
Syed Fida Hassan ◽  
Toshikazu Akahori ◽  
Mitsuo Niinomi
Keyword(s):  
High Temperature ◽  
Elevated Temperatures ◽  
Atmospheric Condition ◽  
Tensile Tests ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Uniaxial Tensile ◽  
Elongation To Failure ◽  
Uniaxial Tensile Stress ◽  
High Temperature Tensile

Ti-29Nb-13Ta-4.6Zr has been recently developed as a biomaterial showing most potential. The study here was conducted to investigate the high temperature deformation behavior under uniaxial tensile stress at various temperatures (i.e., 700°C, 800°C and 900°C) with different initial strain rates at atmospheric condition. Results of the high temperature tensile tests show a significant improved elongation-to-failure of this novel biomaterial at elevated temperatures compared to open literature, and hence its formability potential.

Constitutive flow stress formulation for aeronautic aluminum alloy AA7075-T6 at elevated temperature and model validation using finite element simulation

2016 ◽  
Vol 230 (6) ◽  
pp. 994-1004
Author(s):  
Uma Maheshwera Reddy Paturi ◽  
Suresh Kumar Reddy Narala
Keyword(s):  
Finite Element ◽  
Aluminum Alloy ◽  
Flow Stress ◽  
Elevated Temperatures ◽  
Constitutive Models ◽  
Absolute Error ◽  
Machining Process ◽  
Strain Rates ◽  
Average Absolute Error ◽  
Wide Range

A judicious material constitutive model used as input to the numerical codes to denote elastic, plastic, and thermomechanical behavior under elevated temperatures and strain rates is essential to analyze and design a process. This work describes the formulation of different constitutive models, such as Johnson–Cook, Zerilli–Armstrong, Arrhenius, and Norton–Hoff models for high-strength aeronautic aluminum alloy AA7075-T6 under a wide range of deformation temperatures and strain rates. The adeptness of the formulated models is evaluated statistically by comparing the value of the correlation coefficient and average absolute error between experimental and predicted flow stress results, and numerically when simulating AA7075-T6 machining process. Though all the models show a reasonable degree of accuracy of fit, based on the average absolute error of the data and finite element predictions when simulating the AA7075-T6 machining process, Zerilli–Armstrong model can offer an accurate and precise estimate and is very close to the experimental results over the other models.

Mechanical properties of a 20 vol % SiC whisker-reinforced, yttria-stabilized, tetragonal zirconia composite at elevated temperatures

1995 ◽  
Vol 10 (1) ◽  
pp. 113-118 ◽  
Author(s):  
S.E. Dougherty ◽  
T.G. Nieh ◽  
J. Wadsworth ◽  
Y. Akimune
Keyword(s):  
Grain Size ◽  
High Temperature ◽  
Elevated Temperatures ◽  
Tetragonal Zirconia ◽  
Tensile Tests ◽  
Engineering Properties ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Deformation Properties ◽  
Before And After

The high-temperature deformation behavior of a SiC whisker-reinforced, yttria-stabilized, tetragonal zirconia polycrystalline composite containing 20 vol % SiC whiskers (SiC/Y-TZP) has been investigated. Tensile tests were performed in vacuum at temperatures from 1450 °C to 1650 °C and at strain rates from 10−3 to 10−5 s−1. The material exhibits useful high-temperature engineering properties (e.g., ∼100 MPa and 16% elongation at T = 1550 °C and at a strain rate of ∼10−4 s−1). The stress exponent was determined to be n ≍ 2. Scanning electron microscopy was used to characterize the grain size and morphology of the composites, both before and after deformation. The grain size in the composite was initially fine, but coarsened at the test temperatures; both dynamic and static grain growth were observed. The morphology of ceramic reinforcements appears to affect strongly the plastic deformation properties of Y-TZP. A comparison is made between the properties of monolithic Y-TZP, 20 wt. % Al2O3 particulate-reinforced Y-TZP (Al2O3/Y-TZP), and SiC/Y-TZP composites.

Superplasticity in CP-Titanium Alloys

2007 ◽  
Vol 551-552 ◽  
pp. 373-378 ◽  
Author(s):  
X.J. Zhu ◽  
Ming Jen Tan ◽  
K.M. Liew
Keyword(s):  
High Temperature ◽  
Grain Growth ◽  
Initial Strain Rate ◽  
Tensile Tests ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Uniaxial Tensile ◽  
Step Method ◽  
Commercially Pure ◽  
Effects Of Temperature

In this work, studies were carried out to investigate the superplasticity of a commercially pure (CP) titanium alloy during high temperature deformation. Uniaxial tensile tests were carried out at 600, 750 and 800°C with an initial strain rate from 10-1s-1 to 10-4s-1. It was found that the alloy do not show good superplasticity due fast grain growth at high temperature and cavity. The effects of temperature on the grain growth and cavity phenomena as well as the dynamic recrystallization of the alloy were studied and a ‘two-step-method’ was introduced to increase the superplasticity of the alloy.

Superplastic Micro Deep Drawing of Fine-Grained Nickel at Elevated Temperatures

2007 ◽  
Vol 551-552 ◽  
pp. 545-550
Author(s):  
S. Ding ◽  
Kai Feng Zhang ◽  
Guo Feng Wang
Keyword(s):  
Deep Drawing ◽  
Elevated Temperatures ◽  
Superplastic Forming ◽  
Tensile Tests ◽  
Processing Parameters ◽  
Uniaxial Tensile ◽  
Strain Rates ◽  
Micro Deep Drawing ◽  
Average Grain Size ◽  
Forming Temperature

Superplastic deformation behavior of nanocrystalline nickel was investigated under equibiaxial tension at different strain rates and forming temperatures. The nickel sheets with a thickness of 0.1 mm were prepared by pulse electrodeposition process. The average grain size of the as-deposited nickel was 70 nm and equiaxed. To determine the optimum processing parameters relevant to micro deep drawing, uniaxial tensile tests were carried out at temperatures ranging from 370°C to 500°C and strain rates ranging from 10-4 to 10-3s-1. In the selected temperature and strain rate ranges, the elongation value is larger than 200%, which indicates good superplastic formability of the electrodeposited nickel. Equibiaxial forming was subsequently performed at 370°C and 450°C, using a punch with a diameter of 1mm. The effects of forming temperature, punch rates on deep drawing process were experimentally investigated. The results indicated that the nickel specimens can be readily drawn at 450°C and punch rates ranging from 0.1mm• min-1 to 5mm• min-1. TEM and SEM were also used to examine microstructures of the as-deposited nickel sheet and deformed nickel specimens. The observations showed that significant grain growth occurs even at low superplastic forming temperatures. Microstructure was found to depend on the stress state and level of deformation.

scholarly journals A Flow Stress Model of 300M Steel for Isothermal Tension

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 252
Author(s):  
Rongchuang Chen ◽  
Shiyang Zhang ◽  
Xianlong Liu ◽  
Fei Feng
Keyword(s):  
Flow Stress ◽  
Constitutive Model ◽  
Tensile Deformation ◽  
Flow Behavior ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Model Parameters ◽  
Average Deviation ◽  
Cross Sectional ◽  
300M Steel

To investigate the effect of hot working parameters on the flow behavior of 300M steel under tension, hot uniaxial tensile tests were implemented under different temperatures (950 °C, 1000 °C, 1050 °C, 1100 °C, 1150 °C) and strain rates (0.01 s−1, 0.1 s−1, 1 s−1, 10 s−1). Compared with uniaxial compression, the tensile flow stress was 29.1% higher because dynamic recrystallization softening was less sufficient in the tensile stress state. The ultimate elongation of 300M steel increased with the decrease of temperature and the increase of strain rate. To eliminate the influence of sample necking on stress-strain relationship, both the stress and the strain were calibrated using the cross-sectional area of the neck zone. A constitutive model for tensile deformation was established based on the modified Arrhenius model, in which the model parameters (n, α, Q, ln(A)) were described as a function of strain. The average deviation was 6.81 MPa (6.23%), showing good accuracy of the constitutive model.

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.

Experimental Investigation of Ti-6Al-4V with a Biaxial Tensile Test Setup at Elevated Temperature

2014 ◽  
Vol 622-623 ◽  
pp. 273-278 ◽  
Author(s):  
Marion Merklein ◽  
Sebastian Suttner ◽  
Adam Schaub
Keyword(s):  
Elevated Temperature ◽  
Elevated Temperatures ◽  
Tensile Tests ◽  
Advanced Materials ◽  
Uniaxial Tensile ◽  
Plastic Yielding ◽  
Characterization Methods ◽  
Specific Strength ◽  
Biaxial Tensile ◽  
Stress States

The requirement for products to reduce weight while maintaining strength is a major challenge to the development of new advanced materials. Especially in the field of human medicine or aviation and aeronautics new materials are needed to satisfy increasing demands. Therefore the titanium alloy Ti-6Al-4V with its high specific strength and an outstanding corrosion resistance is used for high and reliable performance in sheet metal forming processes as well as in medical applications. Due to a meaningful and accurate numerical process design and to improve the prediction accuracy of the numerical model, advanced material characterization methods are required. To expand the formability and to skillfully use the advantage of Ti-6Al-4V, forming processes are performed at elevated temperatures. Thus the investigation of plastic yielding at different stress states and at an elevated temperature of 400°C is presented in this paper. For this reason biaxial tensile tests with a cruciform shaped specimen are realized at 400°C in addition to uniaxial tensile tests. Moreover the beginning of plastic yielding is analyzed in the first quadrant of the stress space with regard to complex material modeling.

The High Temperature Deformation Behavior of A Cr2Nb Ordered Intermetallic System

1990 ◽  
Vol 213 ◽  
Author(s):  
G. E. Vignoul ◽  
J.M. Sanchez ◽  
J. K. Tien
Keyword(s):  
Deformation Behavior ◽  
Elevated Temperatures ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Deformation Law ◽  
Ordered Intermetallic ◽  
Intermetallic System ◽  
Increasing Temperature ◽  
Stress Term

ABSTRACTA basic characterization of the deformation behavior of Cr2Nb by microindention at ambient and elevated temperatures (up to 1400 °C) was undertaken. The microhardness of this system was seen to decrease with increasing temperature, from 1040 MPa at 25°C to 322 MPa at 1400 °C. Further, the microindention creep behavior of this system was studied by varying time on load at T = 1000 and 1200°C. Analysis of the data showed that m = 24 and Qapp = 477.61 kJ/mole. These unusually high values are indicative of the existence of an effective resisting stress against creep. When the data was fit against a microindention creep deformation law which was modified to incorporate an effective resisting stress term, it was determined that m = 4.5, Qcreep = 357 kJ/mole and the resisting stress term σr = 300 MPa.

Oxidation Effects during High Temperature Deformation of CP Ti Alloy

2007 ◽  
Vol 539-543 ◽  
pp. 3678-3683
Author(s):  
Ming Jen Tan ◽  
X.J. Zhu ◽  
S. Thiruvarudchelvan ◽  
K.M. Liew
Keyword(s):  
High Temperature ◽  
Oxide Film ◽  
High Temperatures ◽  
Pure Titanium ◽  
Initial Strain Rate ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Uniaxial Tensile ◽  
Commercially Pure Titanium ◽  
Commercially Pure

This work reports the influence of oxidation on the superplasticity of commercially pure titanium at high temperatures. Uniaxial tensile tests were conducted at temperatures in the range 600-800°C with an initial strain rate of 10s-1 to 10s-3. This study shows that oxidization at the surface of the alloy causes oxide film on the surface of commercially pure titanium alloy, and the thickness of oxide film increase with increasing exposure time and temperature. XRD analysis shows that the oxide film consists of TiO2. Because this oxide film is very brittle, it can induce clefts and degrade the ductility of the titanium at high temperatures. The mechanism of the initial clefts was investigated and a model for the cleft initiation and propagation during high temperature tensile test was proposed.

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