Study on Hot Processing Maps and Flow Instability of 1235 Al Alloy Treated by Different Methods of Purification

2011 ◽  
Vol 399-401 ◽  
pp. 1870-1877
Author(s):  
Gao Sheng Fu ◽  
Wen Duan Yan ◽  
Hong Ling Chen ◽  
Gui Qing Chen ◽  
Chao Zeng Cheng
Keyword(s):  
Strain Rate ◽  
Power Dissipation ◽  
Flow Instability ◽  
Al Alloy ◽  
Processing Maps ◽  
Hot Workability ◽  
Optimum Processing ◽  
Lower Strain ◽  
Power Dissipation Efficiency ◽  
Higher Temperature

Based on the theory of processing map proposed by PRASAD, the power dissipation maps, the hot deformation instability maps and the hot processing maps of 1235 Al alloys treated by different methods of purification were built, and the effects of purification and deformation conditions at elevated-temperature on hot workability of 1235 Al alloy were analyzed. At the same time the optimum processing region and flow instability region were determined. The results show that the hot processing map of 1235 Al alloy has two instability zones in the temperature range of 300-500°C and in the strain rate ranging from 0.01s-1to 10.0s-1up to a true strain of 0.7, that is, one zone lying in the range of lower temperature and higher strain rate, the other zone in the range of higher temperature and mid strain rate. The purification effect has significant impact on hot workability of the alloy. It is found that the optimum processing region of 1235 Al alloy treated by high-efficient purification treatment is present in the range of higher temperature and lower strain rate zone, and its power dissipation efficiency is about 46%; while the optimum processing region of 1235 Al alloys treated by conventional refining treatment is present in the range of mid-temperature and lower strain rate zone or in the range of higher temperature and strain rate zone, and its power dissipation efficiency is about 23-29%. The results of observation of the deformation microstructure of 1235 Al alloy are in accordance with that of the hot processing maps of the alloy, thus showing that the calculation results of the hot processing maps are reliable.

Hot Workability Analysis of Extruded Mg-Zn-Mn-Y Magnesium Alloys with Different Phases

2012 ◽  
Vol 184-185 ◽  
pp. 1010-1016
Author(s):  
Wei Wei He ◽  
Kun Zhang ◽  
Min Huang ◽  
Sheng Long Dai
Keyword(s):  
Strain Rate ◽  
Magnesium Alloys ◽  
Power Dissipation ◽  
Rate Sensitivity ◽  
Processing Maps ◽  
Hot Workability ◽  
Compression Tests ◽  
Secondary Phases ◽  
Forming Process ◽  
Power Dissipation Efficiency

Workability, an important parameter in magnesium alloys forming process, can be evaluated by means of processing maps on the basis of dynamic materials model, constructed from experimentally generated flow stress variation with respect to strain, strain rate and temperature. To obtain the processing maps of extruded Mg-Zn-Mn-Y magnesium alloy with different secondary phases (I-phase and W-phase), hot compression tests were performed over a range of temperatures 523–673 K and strain rates 0.001~10s-1. The response of strain-rate sensitivity (m-value), power dissipation efficiency (ζ-value) and instability parameter (n-value) to temperature and strain rate were evaluated. By the superimposition of the power dissipation and the instability maps, the dynamic recrystallization (DRX) and instability zones were identified and validated through micrographs. The observations were performed in order to describe the behavior of the material under hot forming operation in terms of material damage and micro-structural modification.

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.

Development of Processing Maps for 3003 Al Alloy

2011 ◽  
Vol 291-294 ◽  
pp. 306-310 ◽  
Author(s):  
Gui Qing Chen ◽  
Gao Sheng Fu ◽  
Wen Duan Yan ◽  
Chao Zeng Cheng ◽  
Ze Chang Zou
Keyword(s):  
Strain Rate ◽  
Flow Instability ◽  
Hot Working ◽  
Al Alloy ◽  
Processing Maps ◽  
Isothermal Compression ◽  
Instability Domain ◽  
Optimum Parameters ◽  
Dynamic Materials ◽  
Dynamic Materials Model

The 3003 Al alloy was deformed by isothermal compression in the range of deformation temperature 300-500 °C at strain rate 0.0l-10.0 s-1 with Gleeble-1500 thermal simulator. Processing maps at a strain of 0.6 for hot working were developed on a dynamic materials model. The maps exhibit a flow instability domain at about 300 °C-380 °C and 1.0-10.0 s-1. DRX occurs extensively in the temperature range of 450-500 °C and at the strain rate of 10.0 s-1. The optimum parameters of hot working for 3003 Al alloy at the strain of 0.6 are confined at 500 °C and 10.0 s-1 with the highest efficiency (37%).

scholarly journals Characterization of Microstructural Evolution for a Near-α Titanium Alloy with Different Initial Lamellar Microstructures

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1045 ◽  
Author(s):  
Hui Li ◽  
Zhanglong Zhao ◽  
Yongquan Ning ◽  
Hongzhen Guo ◽  
Zekun Yao
Keyword(s):  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Microstructural Evolution ◽  
Power Dissipation ◽  
Flow Instability ◽  
Lamellar Microstructure ◽  
Rate Sensitivity ◽  
Lamellar Thickness ◽  
Processing Maps ◽  
Deformation Behaviors

The effects of initial lamellar thickness on microstructural evolution and deformation behaviors of a near-α Ti-5.4Al-3.7Sn-3.3Zr-0.5Mo-0.4Si alloy were investigated during isothermal compression in α + β phase field. Special attention was paid to microstructural conversion mechanisms for α lamellae with different initial thicknesses. The deformation behaviors, including flow stress, temperature sensitivity, and strain rate sensitivity, and processing maps and their dependence on initial lamellar thickness were discussed. The detailed microstructural characterizations in different domains of the developed processing maps were analyzed. The results showed that the peak efficiency of power dissipation decreased with increasing initial lamellar thickness. The interaction effects with different extents of globularization, elongating, kinking, and phase transformation of lamellar α accounted for the variation in power dissipation. The flow instability region appeared to expand more widely for thicker initial lamellar microstructures during high strain rate deformation due to flow localization and local lamellae kinking. The electron backscatter diffraction (EBSD) analyses revealed that the collaborative mechanism of continuous dynamic recrystallization (CDRX) and discontinuous dynamic recrystallization (DDRX) promoted the rapid globularization behavior for the thinnest acicular initial microstructure, whereas in case of the initial thick lamellar microstructure, CDRX leading to the fragmentation of lamellae was the dominant mechanism throughout the deformation process.

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.

scholarly journals Microstructure Evolution and Hot Deformation Behavior of a CuNiSn Alloy

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 451
Author(s):  
Yexin Jiang ◽  
Xu Wang ◽  
Zhou Li ◽  
Zhu Xiao ◽  
Xiaofei Sheng ◽  
...  
Keyword(s):  
Flow Stress ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Power Dissipation ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Flow Instability ◽  
True Strain ◽  
Hot Deformation Behavior ◽  
Power Dissipation Efficiency

The hot deformation behavior of Cu-20.0Ni-5.0Sn-0.25Zn-0.22Mn was investigated using a Gleeble-3500 thermal simulator with a temperature range from 720 °C to 880 °C and a strain rate range from 0.001 s−1 to 1 s−1. The results show that the flow stress increased with the increase of the strain rate and the decrease of the temperature. The constitutive equation of the alloy was established based on the peak flow stress. Figures of the power dissipation efficiency and flow instability with the variable of the true strain from 0.2 to 0.8 displayed the dynamic change of power dissipation efficiency and the instability area. The domain of 730–770 °C and 0.001–0.01 s−1 possessed a power dissipation efficiency over 40% throughout the whole deformation. The flow instability always appeared at a high strain rate from 0.1 s−1 to 1 s−1 during the whole deformation process. The nucleation site of the dynamic recrystallization generally appeared along the grain boundaries, indicating the discontinuous dynamic recrystallization mechanism. The appropriate conditions for deformation with a true strain of 0.9 is in a safe domain (820–860 °C with a strain rate of 0.001–0.01 s−1). There were four kinds of variation tendencies of the power dissipation efficiency with the increase of the true strain under various conditions, suggesting a changing situation for the main softening mechanisms.

Characterization of Hot Deformation of Nb-V-Ti Microalloyed Steel Using Processing Map

2009 ◽  
Vol 79-82 ◽  
pp. 1439-1442
Author(s):  
Song Xiang ◽  
Guo Quan Liu
Keyword(s):  
Strain Rate ◽  
Power Dissipation ◽  
Hot Deformation ◽  
Microalloyed Steel ◽  
Rate Sensitivity ◽  
Strain Rate Range ◽  
Processing Maps ◽  
Peak Efficiency ◽  
Power Dissipation Efficiency ◽  
Working Parameters

The hot deformation behavior of Nb-V-Ti microalloyed steel in the temperature range of 850°C～1100°C and the strain rate range of 0.001s-1～30s-1 was investigated by establishing the processing maps. The strain rate sensitivity (m), power dissipation efficiency (η) and instability parameter were calculated based on the experimental compression data and are plotted in the temperature–strain rate plane to obtain power dissipation and instability maps. The processing maps exhibit that the deformation at 1000°C and 2s-1 is one peak efficiency of power dissipation of 21%, the deformation at 1050°C and 0.01~0.001 s-1 is another peak efficiency of power dissipation of 45%. The optical microstructure observations show that they represent two dynamic recrystallization domains. Based on the above processing maps, the hot working parameters were optimized.

scholarly journals Hot Workability of 300M Steel Investigated by In Situ and Ex Situ Compression Tests

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 880 ◽  
Author(s):  
Rongchuang Chen ◽  
Haifeng Xiao ◽  
Min Wang ◽  
Jianjun Li
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Hot Working ◽  
Ex Situ ◽  
Lower Strain Rate ◽  
Hot Workability ◽  
Compression Tests ◽  
300M Steel ◽  
Lower Strain

In this work, hot compression experiments of 300M steel were performed at 900–1150 °C and 0.01–10 s−1. The relation of flow stress and microstructure evolution was analyzed. The intriguing finding was that at a lower strain rate (0.01 s−1), the flow stress curves were single-peaked, while at a higher strain rate (10 s−1), no peak occurred. Metallographic observation results revealed the phenomenon was because dynamic recrystallization was more complete at a lower strain rate. In situ compression tests were carried out to compare with the results by ex situ compression tests. Hot working maps representing the influences of strains, strain rates, and temperatures were established. It was found that the power dissipation coefficient was not only related to the recrystallized grain size but was also related to the volume fraction of recrystallized grains. The optimal hot working parameters were suggested. This work provides comprehensive understanding of the hot workability of 300M steel in thermal compression.

scholarly journals Hot Deformation Behaviour and Processing Map of Cast Alloy 825

2021 ◽  
Author(s):  
Munir Al-Saadi ◽  
Christopher Hulme-Smith ◽  
Fredrik Sandberg ◽  
Pär G. Jönsson
Keyword(s):  
Strain Rate ◽  
Vickers Hardness ◽  
Power Dissipation ◽  
Hot Deformation ◽  
Processing Map ◽  
Cast Alloy ◽  
True Strain ◽  
Processing Conditions ◽  
Temperature Range ◽  
Power Dissipation Efficiency

AbstractAlloy 825 is a nickel-based alloy that is commonly used in applications where both high strength and corrosion resistance are required, such as tanks in the chemical, food and petrochemical industries and oil and gas pipelines. Components made from Alloy 825 are often manufactured using hot deformation. However, there is no systematic study to optimise the processing conditions reported in literature. In this study, a processing map for as-cast Alloy 825 is established to maximise the power dissipation efficiency of hot deformation in the temperature range of 950 to 1250 °C at an interval of 50 °C and strain rate range of $$0.01\, {\text{s}}^{ - 1}$$ 0.01 s - 1 to $$10.0\, {\text{s}}^{ - 1}$$ 10.0 s - 1 to a true strain of $$0.7$$ 0.7 using a Gleeble-3500 thermomechanical simulator. The processing conditions are also correlated to the Vickers hardness of the final material, which is also characterised using optical microscopy and scanning electron microscopy, including electron backscattered diffraction. The true stress-true strain curves exhibit peak stresses followed by softening due to occurrence of dynamic recrystallization. The activation energy for plastic flow in the temperature range tested is approximately $$450\,{\text{ kJ mol}}^{ - 1}$$ 450 kJ mol - 1 , and the value of the stress exponent in the (hyperbolic sine-based) constitutive equation, $$n = 5.0$$ n = 5.0 , suggests that the rate-limiting mechanism of deformation is dislocation climb. Increasing deformation temperature led to a lower Vickers hardness in the deformed material, due to increased dynamic recrystallization. Raising the strain rate led to an increase in Vickers hardness in the deformed material due to increased work hardening. The maximum power dissipation efficiency is over $$35\%$$ 35 % , obtained for deformation in the temperature range 1100-1250 °C and a strain rate of $$0.01\, {\text{s}}^{ - 1}$$ 0.01 s - 1 -$$0.1\, {\text{s}}^{ - 1}$$ 0.1 s - 1 . These are the optimum conditions for hot working.

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.

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