scholarly journals Hot deformation behaviour of bamboo leaf ash–silicon carbide hybrid reinforced aluminium based composite

2020 ◽  
Vol 7 ◽  
pp. 17
Author(s):  
Kenneth Kanayo Alaneme ◽  
Saheed Adeoye Babalola ◽  
Lesley Heath Chown ◽  
Michael Oluwatosin Bodunrin
Keyword(s):  
Activation Energy ◽  
Flow Stress ◽  
Dynamic Recovery ◽  
Deformation Behaviour ◽  
Strain Rates ◽  
Dominant Deformation Mechanism ◽  
Bamboo Leaf Ash ◽  
Gleeble 3500 ◽  
Hot Deformation Behaviour ◽  
Microstructural Examination

Isothermal compression testing of BLA-SIC hybrid reinforced Aluminium composites was performed on Gleeble 3500 thermomechanical simulator under different deformation temperatures (300–400 °C) and strain rates (0.01–1 s‑1). The flow behaviour and the softening mechanisms were established using the trend of the stress-strain curves, activation energy and microstructural examination. The results showed that flow stress increased with decreasing temperature; but was not entirely strain rate sensitive − a characteristic identified in some Al 6XXX based metallic systems. Also, uncharacteristic flow stress oscillations were observed at strain rates of 0.01 and 0.1 s‑1 while steady state flow stress was observed at 1 s‑1. The hot working activation energy was ∼290.5 kJ/mol which was intermediate to the range of 111–509 kJ/mol reported in literature for various Al based composites. It was proposed that at strain rates of 0.01 and 0.1 s‑1, dynamic recrystallization and/or dislocations-reinforcements interactions were the dominant deformation mechanism(s), while at 1 s‑1, dynamic recovery was predominant.

Prediction of Microstructure During High Temperature Forming of Ti-6Al-4V Alloy

2004 ◽  
Vol 449-452 ◽  
pp. 189-192 ◽  
Author(s):  
You Hwan Lee ◽  
T.J. Shin ◽  
Jong Taek Yeom ◽  
Nho Kwang Park ◽  
S.S. Hong ◽  
...  
Keyword(s):  
Activation Energy ◽  
Finite Element Analysis ◽  
Finite Element ◽  
High Temperature ◽  
Flow Stress ◽  
Rate Sensitivity ◽  
Strain Rates ◽  
Element Analysis ◽  
Strain Data ◽  
Final Microstructure

Prediction of final microstructures after high temperature forming of Ti-6Al-4V alloy was´attempted in this study. Using two typical microstructures, i.e., equiaxed and Widmanstätten microstructures, compression test was carried out up to the strain level of 0.6 at various temperatures (700 ~ 1100°C) and strain rates (10-4 ~ 102/s). From the flow stress-strain data, parameters such as strain rate sensitivity (m) and activation energy (Q) were calculated and used to establish constitutive equations for both microstructures. Then, finite element analysis was performed to predict the final microstructure of the deformed body, which was well accorded with the experimental results.

Deformation Behavior and Microstructure Evolution of 6063 Alloy during Hot Compression

2018 ◽  
Vol 913 ◽  
pp. 63-68 ◽  
Author(s):  
Zhu Hua Yu ◽  
Da Tong Zhang ◽  
Wen Zhang ◽  
Cheng Qiu
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Shear Bands ◽  
Hot Compression ◽  
Al Alloy ◽  
Strain Rates ◽  
Compression Tests ◽  
Softening Effect ◽  
6063 Al Alloy ◽  
Gleeble 3500

Hot compression tests of homogenized 6063 Al alloy were carried out in the temperatures range from 390°C to 510°C and strain rates from 1s-1 to 20s-1 on a Gleeble-3500 thermal simulation machine. The results showed that the flow stress decreased with increasing deformation temperature or decreasing strain rate. The dynamic softening effect was more obvious when the alloy was deformed at strain rate of 20 s-1. The Arrhenius-type constitutive equation with strain compensation can accurately describe the flow stress of 6063 aluminum alloy during hot compression. Shear bands appeared in grains interior when the alloy deformed at high strain rates, corresponding to high Zenner-Hollomon (Z) parameters. When deformed under the conditions with low Z parameters, the dynamic recrystallization started occurred.

Hot Deformation Behavior of As-Cast Mg-9Gd-2.5Y-Nd-0.5Zr Mg Alloy

2014 ◽  
Vol 788 ◽  
pp. 45-51
Author(s):  
Yong Biao Yang ◽  
Zhi Min Zhang ◽  
Feng Li Ren ◽  
Qiang Wang
Keyword(s):  
Flow Stress ◽  
Magnesium Alloy ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Dynamic Recovery ◽  
Strain Rates ◽  
Hot Deformation Behavior ◽  
Hollomon Parameter ◽  
Temperature Range ◽  
Parameter Function

The elevated temperature flow stress behavior of Mg-9Gd-2.5Y-1Nd-0.5Zr magnesium alloy was carried out by Gleeble-1500 thermal mechanical simulator in the temperature range of 460-520°C and in strain rates of 0.0005~1s-1 at a strain of 0.6. The optical microscopy was used for microstructure characterization. The results showed that the flow stress increases with increasing strain rates and decreasing temperature. All the deformed magnesium alloy specimens show a dynamic recovery characters in the temperature range from 460~500°C, and show dynamic recrystallization characters at 520°C. The flow stress of this alloy can be represented by Zener-Hollomon parameter function, and values of related parameters A, α and n, are 2.24×1013s-1、0.027MPa-1 and 2.93, respectively. Its activation energy for hot deformation Q is 212.6kJ/mol.

High-Temperature Deformation of Yba2Cu307-8 With Ag Additions

1989 ◽  
Vol 169 ◽  
Author(s):  
J.L. Routbort ◽  
K.C. Goretta ◽  
J.P. Singh
Keyword(s):  
Activation Energy ◽  
Steady State ◽  
High Temperature ◽  
Flow Stress ◽  
Compressive Strain ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Strain Rates ◽  
Steady State Flow ◽  
Ag Additions

AbstractThe steady‐state flow stress of YBa2Cu3O7‐δ containing 15 to 30 vol.% Ag has been measured in air at nearly constant compressive strain rates between 5 x 10‐6 and 1 x 10‐4 s‐1 from 830 to 900°C. Addition of Ag dramatically decreases the flow stress compared to that of the pure superconductor, but the stress exponents and the activation energy for deformation remain unchanged.

Modelling the High Temperature Deformation of Ti-6Al-4V

2010 ◽  
Vol 654-656 ◽  
pp. 879-882 ◽  
Author(s):  
Ji Kang Zhong ◽  
Matthew S. Dargusch ◽  
Chris H.J. Davies
Keyword(s):  
Volume Fraction ◽  
Deformation Behaviour ◽  
Constitutive Models ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Strain Rates ◽  
Initial Sample ◽  
Soft Phase ◽  
Hot Deformation Behaviour ◽  
Good Agreement

The hot deformation behaviour of the alpha / beta Ti-6Al-4V alloy was investigated at various temperatures and strain rates by means of compression and torsion tests. As expected, the peak flow stress increased with increasing strain rate and decreased as the initial sample temperature was increased. The different flow behaviours observed are discussed in terms of the volume fraction of each phase. The dual phase Ti-6Al-4V alloy was assumed to be a composite material containing a soft phase and a hard phase. By taking into consideration the phase-to-phase interaction and volume fraction change with temperature, constitutive models are proposed to simulate the deformation behaviours. By application of the rule of mixtures the modelled yield stresses showed good agreement with the experiment results.

scholarly journals A Comparative Study on Modified Johnson–Cook and Arrhenius-Type Constitutive Models to Predict the Hot Deformation Behaviour of Molybdenum-Hafnium-Carbide Alloy

2021 ◽  
Author(s):  
Athar Safari ◽  
Muhammad Imran ◽  
Sabine Weiss
Keyword(s):  
High Temperature ◽  
Flow Stress ◽  
Constitutive Equations ◽  
Hot Deformation ◽  
Deformation Behaviour ◽  
Experimental Results ◽  
Temperature Deformation ◽  
Computational Time ◽  
Strain Rates ◽  
Material Constants

AbstractMolybdenum alloys are commonly used as tool material for high-temperature deformation processes like forming or forging. For these types of application, the material has to withstand static load at elevated temperatures. To investigate the high-temperature performance of the material, uniaxial hot tensile tests were performed on a Mo-1.2% Hf-0.1% C alloy (MHC) over the temperature range of 1173-1473 K with intervals of 100 K and strain rates of 0.001, 0.01 and 0.1 s−1 up to the fracture of the specimen. The flow stress decreases with increase in temperature and the reduction in strain rate. This behaviour could be related to the increasing rate of restoration mechanisms, i.e. dynamic recrystallization or recovery as well as to the decrease in the strain hardening rate. Microstructure of the two most critical hot deformation conditions were shown and compared. Based on modified Johnson–Cook and strain-compensated Arrhenius-type models, constitutive equations were established to predict the high-temperature flow stress of the respective MHC alloy. The accuracy of both models was evaluated by comparing the predicted stress values and the values obtained from experiments. Correlation coefficient, average absolute relative error, the number of material constants involved and the computational time required for evaluating the constants were calculated to quantify and compare the precision of both models. The flow stress values predicted by the constitutive equations are in good agreement with the experimental results. At lower strain rates (0.001 and 0.01 s−1), distinct deviation from the experimental results can be observed for the modified Johnson–Cook model. Despite the longer evaluation time and the larger number of material constants, the deformation behaviour, tracked by the Arrhenius-type model is more accurate throughout the entire deformation process.

Deformation Behavior of AZ31 Magnesium Alloy at Elevated Temperature

2013 ◽  
Vol 652-654 ◽  
pp. 1976-1979
Author(s):  
Ya Lin Lu ◽  
Xing Cheng Li ◽  
Hong Jin Wang ◽  
Xiao Ping Li
Keyword(s):  
Elevated Temperature ◽  
Flow Stress ◽  
Magnesium Alloy ◽  
Process Parameters ◽  
Deformation Behavior ◽  
Deformation Process ◽  
Strain Rates ◽  
Hot Compression Test ◽  
Dynamic Recrystallisation ◽  
Gleeble 3500

Hot compression test for AZ3l magnesium alloy at deformation temperatures of 523-723K and strain rates of 0.01-10s-1 were carried out using Gleeble-3500 thermo-mechanical simulator. The experimental results show that the flow stress and microstructure vary apparently with deformation process parameters. Microstructure observations show that dynamic recrystallisation (DRX) takes place during the deformation. The characteristic with the dynamic recrystallization change with the process parameters.

Hot Deformation Behaviour and Microstructure in Al-Cu-Li Alloy Containing Small Amount of Ag and Mg

2006 ◽  
Vol 519-521 ◽  
pp. 1925-1930 ◽  
Author(s):  
Zhi Guo Chen ◽  
Zi Qiao Zheng ◽  
Dong Feng Han
Keyword(s):  
Flow Stress ◽  
Hot Deformation ◽  
Deformation Temperature ◽  
Deformation Behaviour ◽  
Flow Characteristics ◽  
Hollomon Parameter ◽  
Transmission Electron ◽  
Deformation Behaviors ◽  
Hot Deformation Behaviour ◽  
Peak Value

The hot deformation behaviors and microstructure in Al-Cu-Li alloy containing small amount of Ag and Mg were investigated by transmission electron microscopy and isothermal compression tests.When the strain rate is 0.1, 0.01 and 0.001s-1(the deformation temperature within the range of 360-520􀀀 ) and 1 s-1(deformation temperature 520 􀀀 )respectively, the flow stress decreases after a peak value, showing dynamic recrystallization,while the steady-state flow characteristics exist on the other deformation conditions. The flow stress of Al-Cu-Li-Mg-Ag alloy during hot deformation can be expressed by a Zener-Hollomon parameter in the hyperbolic-sine function with the hot deformation activation energyDH of 250.45kJ/mol. The dislocations may climb with support from many vacancies generated during hot deformation, thus forming lots of helical dislocations. The dynamic precipitation and successive dynamic particles coarsening during hot compression have been assumed to be responsible for further flow softening when deformed at low strain rates.

scholarly journals Hot Deformation Behaviour of Mn–Cr–Mo Low-Alloy Steel in Various Phase Regions

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1255 ◽  
Author(s):  
Ivo Schindler ◽  
Petr Opěla ◽  
Petr Kawulok ◽  
Jaroslav Sojka ◽  
Kateřina Konečná ◽  
...  
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Behaviour ◽  
True Strain ◽  
Coarse Grained ◽  
Peak Strain ◽  
Compression Tests ◽  
Wide Range ◽  
Hot Deformation Behaviour

The deformation behaviour of a coarse-grained as-cast medium-carbon steel, alloyed with 1.2% Mn, 0.8% Cr and 0.2% Mo, was studied by uniaxial compression tests for the strain rates of 0.02 s−1–20 s−1 in the unusually wide range of temperatures (650–1280 °C), i.e., in various phase regions including the region with predominant bainite content (up to the temperature of 757 °C). At temperatures above 820 °C, the structure was fully austenitic. The hot deformation activation energies of 648 kJ·mol−1 and 364 kJ·mol−1 have been calculated for the temperatures ≤770 °C and ≥770 °C, respectively. This corresponds to the significant increase of flow stress in the low-temperature bainitic region. Unique information on the hot deformation behaviour of bainite was obtained. The shape of the stress-strain curves was influenced by the dynamic recrystallization of ferrite or austenite. Dynamically recrystallized austenitic grains were strongly coarsened with decreasing strain rate and growing temperature. For the austenitic region, the relationship between the peak strain and the Zener–Hollomon parameter has been derived, and the phenomenological constitutive model describing the flow stress depending on temperature, true strain rate and true strain was developed. The model can be used to predict the forming forces in the seamless tubes production of the given steel.

Effect of SN Additions on Superplasticity in Al-Mg-Mn-Sc Alloys

1999 ◽  
Vol 601 ◽  
Author(s):  
C. H. Henager ◽  
J. S. Vetrano ◽  
V. Y. Gertsman ◽  
S. M. Bruemmer
Keyword(s):  
Activation Energy ◽  
Flow Stress ◽  
Strain Rate ◽  
Stress And Strain ◽  
Strain Rates ◽  
Fine Grain ◽  
Heat Treated ◽  
Main Effect ◽  
Stress And Strain Rate ◽  
Stress Activation

AbstractIdentical Al-Mg-Mn-Sc alloys without and with 0.034-wt% Sn additions were fabricated, heat-treated, and tensile tested in a fine-grain (d < 6 pm) condition at four strain rates from 10−2 to 10−4 s−1 and at temperatures from 723K to 823K. Alloys with Sn additions exhibited reduced failure strains at 723K but higher failure strains at 823K for the slowest strain rates. The effect of Sn on flow stress, activation energy for flow stress, and strain rate exponent was explored and was found to be small. The main effect of Sn was suggested to be in reducing cavitation by allowing a redistribution of stress at critical hetero-junctions in the alloys.

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