The Change of Processing Maps in Hot Compression Procession for Ti-6.0Al-7.0Nb Biomedical Titanium Alloy

2014 ◽  
Vol 906 ◽  
pp. 254-258
Author(s):  
Yan Hui Liu ◽  
Ze Kun Yao ◽  
Yong Quan Ning ◽  
Hong Zhen Guo ◽  
Zhang Long Zhao
Keyword(s):  
Titanium Alloy ◽  
Power Dissipation ◽  
Flow Instability ◽  
True Strain ◽  
Strain Rates ◽  
Processing Maps ◽  
Compression Tests ◽  
Β Phase ◽  
Different Temperatures ◽  
Biomedical Titanium Alloy

Isothermal compression tests were carried out on Ti-6.0Al-7.0Nb biomedical titanium alloy at the temperatures of 750900°C (all below β phase transition temperature about 1010°C) and strain rates of 0.0011.0s-1. The processing maps were constructed to evaluate the efficiency of power dissipation (η) and recognize the flow instability regimes. True strain takes great effect on the efficiency of power dissipation η under the different temperatures and strain rates. The value of power dissipation η increases from 0.1 to 0.7 in most areas. When the strain is 0.9, the value of power dissipation η in most regimes is from 30% to 40%. There are two instability regimes respectively located around 780°C/1.0s-1 and 860-900°C/0.001-0.01s-1 when the strains are below 0.5. One of the instability regimes disappears when the strains are 0.5-0.7. When the strain is 0.9, there are still two instability regimes. The safe regime located around 780-840°C/0.1-0.01s-1, and hot deformation can be carried out in this area.

scholarly journals Investigation on the Thermal Deformation Behavior of the Nickel-Based Superalloy Strengthened by γ′ Phase

Crystals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 125
Author(s):  
Haiping Wang ◽  
Dong Liu ◽  
Jianguo Wang ◽  
Yongzhao Shi ◽  
Yong Zheng ◽  
...  
Keyword(s):  
Flow Stress ◽  
Power Dissipation ◽  
Deformation Behavior ◽  
Processing Map ◽  
Flow Instability ◽  
True Strain ◽  
Processing Condition ◽  
Strain Rates ◽  
Processing Maps ◽  
Nickel Based Superalloy

The isothermal compression tests of the nickel-based superalloy Waspaloy were carried out under various temperatures from 1040 to 1120 °C and strain rates from 0.01 to 10 s−1 with the height reduction of 60% and the flow stress curves were obtained. The curves show that the flow stress is greatly affected by the temperature and strain rates. Regression analysis of the experimental results was carried out to learn about the deformation behavior through the Arrhenius equation and came to the conclusion that the activation energy of Waspaloy is 669.7 kJ/mol. The constitutive equation of the Waspaloy was constructed. Meanwhile, the processing maps of the Waspaloy for the power dissipation and the flow instability were constructed. The processing map of the power dissipation and the flow instability depicts that the strain plays a major role in the processing maps. The instability zone is prone to appear at higher strain rates with the increasing strains. According to the instability processing map, there are three unsafe regimes around 1040–1120 °C/1.5–10 s−1, 1040–1080 °C/0.02–0.1 s−1 and 1110–1120 °C/0.02–0.3 s−1 that should be avoided during deformation process. The power dissipation maps show that the maximum dissipation is prone to appear at low strain rates (0.01 s−1) when the strain is about 0.1~0.6 while at middle strain rates (0.1–1 s−1) when the strain is over 0.6, and when the true strain is 0.9, the optimum processing condition is around 1060–1120 °C/0.1–1 s−1. The dynamic microstructures under different temperatures and strain rates were also obtained. We concluded that lower strain rates and higher temperatures are more applicable to obtain fully-recrystallized microstructures. Based on the instability maps and the power dissipation maps and the dynamic microstructures, the optimum deformation conditions are determined to be around 1080–1100 °C/0.1–1 s−1 and 1040–1120 °C/0.01 s−1.

Effect of True Strain on Processing Maps for Processed Ni-Based Superalloy below γ΄-Transus Temperature

2014 ◽  
Vol 941-944 ◽  
pp. 1459-1462
Author(s):  
Guo Bao Yang ◽  
Ze Kun Yao ◽  
Yan Hui Liu ◽  
Yang Nan ◽  
Yong Quan Ning
Keyword(s):  
Power Dissipation ◽  
Flow Instability ◽  
True Strain ◽  
Small Strain ◽  
Processing Maps ◽  
Compression Tests ◽  
Homogeneous Microstructure ◽  
Transus Temperature ◽  
Small Decline ◽  
Instability Regime

Isothermal compression tests were carried out on GH4133B superalloy at 940–1060°C (below nominal γ΄-transus temperature of 1080°C) and 0.001–1.0s-1. The processing maps were constructed to evaluate the efficiency of power dissipation (η) and recognize the flow instability regimes. Our investigations demonstrate that true strain takes great effect on processing maps' evolution. At 1020°C/1.0s-1, the efficiency valueηundergoes a small decline at low strains, and then increases linearly from 0.26 to 0.58 at high strains. However, the efficiency value remains high constant (η=0.40) with the increased strain under the condition of 980°C/0.001s-1. As a result, hot deformation can be carried out firstly at 980°C/0.001s-1with small strain about 0.35 and then carried out at 1020°C/1.0s-1to get fine homogeneous microstructure. There are two instability regimes respectively located around 940°C/1.0s-1and 1060°C/0.001s-1when the strains are 0.05–0.40. Moreover, there is another instability regime located around 1060°C/1.0s-1when the strains are 0.45–0.69.

scholarly journals Theoretical-Experimental Analysis of the Workability of the Ni50Cr45N0.6 alloy

2017 ◽  
Vol 62 (1) ◽  
pp. 59-65
Author(s):  
A. Łukaszek-Sołek ◽  
A. Świątoniowski ◽  
K. Celadyn ◽  
J. Sińczak
Keyword(s):  
Strain Rate ◽  
Power Dissipation ◽  
Metal Forming ◽  
Flow Instability ◽  
Deformation Behaviour ◽  
True Strain ◽  
Strain Range ◽  
Rate Sensitivity ◽  
Processing Maps ◽  
Compression Tests

Abstract In this paper, the results of investigations into, and of the analyses of, the hot deformation behaviour of the Ni50Cr45N0.6 alloy were presented. Compression tests were conducted on a Gleeble 3800 thermo-mechanical simulator within the following temperatures range 850-1200°C and within that of the strain rate 1-40 s-1 to the constant true strain of 0.9, for the purpose of fulfilling the objective of obtaining experimental stress date. Those data were taken advantage of for the purpose of calculating the workability parameters, and that means the efficiency of power dissipation η, the flow instability ξ and the strain rate sensitivity m. The processing maps based upon Murty’s criterion were drawn up for the following true strain range: 0.2-0.9, and, subsequently, both processing windows and the flow instability areas were determined. For the alloy being analysed, the most advantageous conditions of metal forming were ascertained within the following range of temperatures: 950-1000°C, and for that of the strain rate amounting to 10-40 s-1, and that because of (occurring at the temperature of 950°C) the peak of the efficiency of power dissipation parameter η, amounting to 22% (in accordance with Murty’s criterion). The flow instability areas identified on the processing maps ought to be avoided in metal forming processes. Experimental rolling tests were also conducted.

Processing Maps of the Ti-6Al-4V Alloy in a Forging Process Design

2015 ◽  
Vol 641 ◽  
pp. 190-197 ◽  
Author(s):  
Aneta Łukaszek-Sołek ◽  
Janusz Krawczyk
Keyword(s):  
Power Dissipation ◽  
True Strain ◽  
Strain Rates ◽  
Processing Maps ◽  
Hollomon Parameter ◽  
Influence Of Process Parameters ◽  
Β Phase ◽  
Wide Range ◽  
Efficiency Parameter ◽  
Power Dissipation Efficiency

The paper presents the results of a complex study of the Ti-6Al-4V alloy, conducted with the application of the dynamic material modelling (DMM) method, in a wide range of temperatures, strain rates and strains. A compression test was carried out in a wide range of temperatures (800 – 1100°C) and strain rates (0.01 – 100 s-1), up to the constant final true strain value of 0.9. The obtained stress-strain curves were a basis for determining deformation activation energy with the use of an Arrhenius plot and a correlation between the Zener-Hollomon parameter and flow stress, for which the constitutive equation proposed by Sellars was used. The power dissipation efficiency parameter was calculated. The maps of power dissipation as the function of temperature and strain rate were plotted in the form of the isoclines of the power dissipation efficiency parameter expressed in %. The processing maps exhibited the range of occurrence and recrystallization of the primary α phase, the degree of the β phase recrystallization progress against the background of the process deformation windows and instability flow domain. An analysis of the influence of process parameters up on the microstructure and hardness changes was conducted.

scholarly journals Dynamic Softening Mechanisms and Microstructure Evolution of TB18 Titanium Alloy during Uniaxial Hot Deformation

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 789
Author(s):  
Qiang Fu ◽  
Wuhua Yuan ◽  
Wei Xiang
Keyword(s):  
Titanium Alloy ◽  
Dynamic Recovery ◽  
True Strain ◽  
Hot Workability ◽  
Compression Tests ◽  
Phase Zone ◽  
Β Phase ◽  
Stability And Instability ◽  
Dynamic Softening ◽  
Transus Temperature

In this study, isothermal compression tests of TB18 titanium alloy were conducted using a Gleeble 3800 thermomechanical simulator for temperatures ranging from 650 to 880 °C and strain rates ranging from 0.001 to 10 s−1, with a constant height reduction of 60%, to investigate the dynamic softening mechanisms and hot workability of TB18 alloy. The results showed that the flow stress significantly decreased with an increasing deformation temperature and decreasing strain rate, which was affected by the competition between work hardening and dynamic softening. The hyperbolic sine Arrhenius-type constitutive equation was established, and the deformation activation energy was calculated to be 303.91 kJ·mol−1 in the (α + β) phase zone and 212.813 kJ·mol−1 in the β phase zone. The processing map constructed at a true strain of 0.9 exhibited stability and instability regions under the tested deformation conditions. The microstructure characteristics demonstrated that in the stability region, the dominant restoration and flow-softening mechanisms were the dynamic recovery of β phase and dynamic globularization of α grains below transus temperature, as well as the dynamic recovery and continuous dynamic recrystallization of β grains above transus temperature. In the instability region, the dynamic softening mechanism was flow localization in the form of a shear band and a deformation band caused by adiabatic heating.

scholarly journals The Investigation on Flow Behavior of Powder Metallurgy Ti-10V-2Fe-3Al Alloy Using the Prasad Stability Criterion

2019 ◽  
Vol 50 (11) ◽  
pp. 5314-5323 ◽  
Author(s):  
Krystian Zyguła ◽  
Marek Wojtaszek ◽  
Oleksandr Lypchanskyi ◽  
Tomasz Śleboda ◽  
Grzegorz Korpała ◽  
...  
Keyword(s):  
Powder Metallurgy ◽  
Power Dissipation ◽  
Hot Deformation ◽  
High Efficiency ◽  
Flow Instability ◽  
Flow Behavior ◽  
Material Model ◽  
Instability Criterion ◽  
Processing Maps ◽  
Compression Tests

Abstract The hot deformation behavior of Ti-10V-2Fe-3Al alloy obtained by the powder metallurgy (PM) method was investigated. Material for the research was produced by blending of elemental powders followed by uniaxial hot pressing. Thermomechanical tests of Ti-10V-2Fe-3Al compacts were carried out to determinate the stress-strain relationships at the temperature range of 800 °C to 1000 °C and strain rate between 0.01 and 10 s−1. Based on the dynamic material model (DMM) theory, processing maps at constant strain value were developed using data obtained from hot compression tests. The processing maps were elaborated for the final strain value, which was 0.9, and with flow instability criterion domains applied to it. Two critical regions associated with the flow behavior of the investigated material were revealed. Microstructural changes during hot deformation at various temperatures and strain rates were discussed. The correlation between calculated efficiency of power dissipation, flow instability criterion, and microstructure evolution was determined. The presence of defects was confirmed in regions predicted by the instability maps. The microstructure of the investigated alloy, corresponding to the high efficiency of power dissipation characterized by the occurrence of dynamic recrystallization (DRX) phenomena, was also shown. Additionally, average hardness values in relation to variable process parameters were designated. Based on the conducted studies and analysis, processing windows for Ti-10V-2Fe-3Al alloy compacts were proposed.

Hot Workability Map for Near-α Titanium Alloy Ti-5.6Al-4.8Sn-2Zr-1Mo-0.35Si-0.7Nd

2012 ◽  
Vol 482-484 ◽  
pp. 1453-1456
Author(s):  
Ming Man Li ◽  
Qui Jian Xun ◽  
Shang Zhou Zhang
Keyword(s):  
Titanium Alloy ◽  
Dynamic Recrystallization ◽  
Power Dissipation ◽  
Processing Map ◽  
Flow Instability ◽  
Shear Bands ◽  
Hot Workability ◽  
Adiabatic Shear Bands ◽  
Β Phase ◽  
Power Dissipation Efficiency

The characterizations of hot working behavior of a near-α titanium alloy using the approach of processing maps are described. Processing map in the α+β region exhibit a domain of the globularization process of lamellar structure and α dynamic recrystallization with a power dissipation efficiency of 0.6-0.9. In the β region the map exhibited a domain centered around 1060°C and 0.1 s-1with a power dissipation efficiency of 0.76 where the β phase undergoes dynamic recrystallization. At higher strain rate flow instability occurs in the α+β region due to adiabatic shear bands formation as well as in the β region due to flow inhomogeneity of β phase.

Processing Map for Hot Deformation of Homogenized AZ61 Mg Alloy

2013 ◽  
Vol 716 ◽  
pp. 240-243 ◽  
Author(s):  
Ching Hao Liao ◽  
Horng Yu Wu ◽  
Shyong Lee ◽  
Cheng Tao Wu ◽  
Chui Hung Chiu
Keyword(s):  
Power Dissipation ◽  
Processing Map ◽  
Flow Instability ◽  
Local Maximum ◽  
Mg Alloy ◽  
Deformation Condition ◽  
Maximum Efficiency ◽  
Processing Maps ◽  
Compression Tests ◽  
Az61 Mg Alloy

Based on the experimental results from the hot compression tests of homogenized cast AZ61 Mg alloy, processing maps were constructed by superimposition of the instability maps over the power dissipation maps. The domain with the efficiency of power dissipation reaching a local maximum and flow instability region were identified in the processing maps. The processing map obtained at a strain of 0.6 exhibited only one domain with local maximum efficiency of power dissipation. The microstructure observations showed that variation in microstructure was related to the deformation condition, which was associated with the variation in efficiency of power dissipation.

Deformation Stability of a Low-Cost Titanium Alloy Used for Petroleum Drilling Pipe

2019 ◽  
Vol 944 ◽  
pp. 887-891
Author(s):  
Long Jiang ◽  
Chun Feng ◽  
Hui Qun Liu ◽  
Le Wang ◽  
Li Hong Han ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Strain Rate ◽  
Flow Instability ◽  
Low Cost ◽  
True Strain ◽  
Strain Rate Range ◽  
Strain Rates ◽  
Arc Melting ◽  
Deformation Stability ◽  
Petroleum Drilling

A new modified low-cost titanium alloy, Ti-Al-X, was designed for petroleum drilling applications. The alloy ingots were prepared by combination of vacuum consumable electrode arc melting, forging/hot rolling, homogenization, and solid-solution/aging treatments. The hot deformation behavior of Ti-Al-X alloy was investigated by a thermal simulation machine Gleeble 1500 at temperature range of 850~1000°C with the strain rate range of 0.001 s-1~1s-1. The deformation resistance significantly decreases with the increase of deformation temperature and the strain rate. The alloy exhibits flow instability under the deformation conditions of strain rates about 0.001 s-1 and temperature above 1000°C, which should be avoided during hot working. In addition, the instability area enlarged in processing map with the increasing of true strain.

scholarly journals Hot Deformation Behavior and Processing Maps of Fe-30Mn-0.11C Steel

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1940 ◽  
Author(s):  
Jianmei Kang ◽  
Yuhui Wang ◽  
Zhimeng Wang ◽  
Yiming Zhao ◽  
Yan Peng ◽  
...  
Keyword(s):  
Dynamic Recrystallization ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
True Strain ◽  
Peak Stress ◽  
Strain Rates ◽  
Processing Maps ◽  
Compression Tests ◽  
Hot Deformation Behavior ◽  
High Deformation

Hot deformation behavior of Fe-30Mn-0.11C steel was investigated. Hot compression tests were carried out at various temperatures ranging from 800 °C to 1200 °C and at different strain rates of 0.01 s−1 to 10 s−1. The constitutive equation based on peak stress was established. Hot processing maps at different strains and recrystallization diagrams were also established and analyzed. The results show that dynamic recrystallization easily occur at high deformation temperatures and low strain rates. Safe and unstable zones are determined at the true strain of 0.6 and 0.7, and the hot deformation process parameters of partial dynamic recrystallization of the tested steel are also obtained.

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