scholarly journals Hot Deformation Behavior and Processing Maps of a New Ti-6Al-2Nb-2Zr-0.4B Titanium Alloy

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2456
Author(s):  
Zhijun Yang ◽  
Weixin Yu ◽  
Shaoting Lang ◽  
Junyi Wei ◽  
Guanglong Wang ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Flow Stress ◽  
Constitutive Equation ◽  
Deformation Mechanism ◽  
Power Dissipation ◽  
Hot Deformation ◽  
Dissipation Rate ◽  
Dynamic Recovery ◽  
Processing Maps ◽  
Temperature Range

The hot deformation behaviors of a new Ti-6Al-2Nb-2Zr-0.4B titanium alloy in the strain rate range 0.01–10.0 s−1 and temperature range 850–1060 °C were evaluated using hot compressing testing on a Gleeble-3800 simulator at 60% of deformation degree. The flow stress characteristics of the alloy were analyzed according to the true stress–strain curve. The constitutive equation was established to describe the change of deformation temperature and flow stress with strain rate. The thermal deformation activation energy Q was equal to 551.7 kJ/mol. The constitutive equation was ε ˙=e54.41[sinh (0.01σ)]2.35exp(−551.7/RT). On the basis of the dynamic material model and the instability criterion, the processing maps were established at the strain of 0.5. The experimental results revealed that in the (α + β) region deformation, the power dissipation rate reached 53% in the range of 0.01–0.05 s−1 and temperature range of 920–980 °C, and the deformation mechanism was dynamic recovery. In the β region deformation, the power dissipation rate reached 48% in the range of 0.01–0.1 s−1 and temperature range of 1010–1040 °C, and the deformation mechanism involved dynamic recovery and dynamic recrystallization.

scholarly journals Microstructure Evolution of Allotropic Materials during Thermomechanical Processing

2012 ◽  
Vol 710 ◽  
pp. 93-100 ◽  
Author(s):  
Cecilia Poletti ◽  
Fernando Warchomicka ◽  
Martina Dikovits ◽  
Simon Großeiber
Keyword(s):  
Phase Transformation ◽  
Dynamic Recrystallization ◽  
Constitutive Equations ◽  
Power Dissipation ◽  
Hot Deformation ◽  
Power Efficiency ◽  
Dynamic Recovery ◽  
Carbon Steels ◽  
Processing Maps ◽  
Strain And Strain Rate

The microstructure developed during hot deformation is the result of deformation mechanisms such as dynamic recovery and dynamic recrystallization. Hot deformation can also result in damage and flow localisation, especially in multiphase metal based materials. Several models have been proposed to correlate the parameters of the deformation process (temperature, strain and strain rate) with the flow behaviour such as the processing maps. They were developed based on the dynamic materials model (DMM) and later a modified DMM introduced some changes in the calculation of the processing maps. The correlation of the relevant microstructural changes with thermodynamic parameters are tested and discussed. The data was obtained by using the Gleeble simulator with in situ quenching facilities. Microstructural studies related to the hot deformation of metals were carried out based on alpha-beta and near beta titanium alloys and on low carbon steels. The results are correlated with the efficiency of power dissipation, and the constitutive equations. In diffusion controlled processes such as dynamic recovery, dynamic recrystallization, phase transformation and pore coarsening are related to high power efficiency, and to low n exponent. The efficiency of power dissipation is more sensitive to the deformation parameters than the constitutive equations for materials with phase transformation.

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.

Processing Maps for TC18 Titanium Alloy Deformed in α+β Region

2012 ◽  
Vol 490-495 ◽  
pp. 3423-3426 ◽  
Author(s):  
Xin Zhao ◽  
Hong Zhao ◽  
Rui Zhang
Keyword(s):  
Titanium Alloy ◽  
Strain Rate ◽  
Power Dissipation ◽  
Strain Rate Range ◽  
Hot Working ◽  
Maximum Efficiency ◽  
Processing Maps ◽  
Compression Tests ◽  
Rate Range ◽  
Temperature Range

The hot deformation characteristics of TC18 titanium alloy were studied in the temperature range 750-850°C and strain rate range 0.001-1 s-1 by using hot compression tests. Processing maps for hot working are developed on the basis of the variations of efficiency of power dissipation with temperature and strain rate. The results reveal that the flow stress of TC18 is sensitive to strain rate. Processing map at stain of 0.6 reveals two domains: one is centered at 750°C and 0.001s-1; another is centered at 850°C and 0.001s-1. The maximum efficiency is more than 60%. According to the maps, the zone with the temperature range of 750-850°C and strain rate range of 0.01-0.001s-1 may be suitable for hot working

Construction of Flow Stress Constitutive Equation for 3Cr1Mo0.25V Steel

2012 ◽  
Vol 567 ◽  
pp. 244-249
Author(s):  
Yu Hua Zhang ◽  
Guang Yu Tan ◽  
Shu Cai Yang
Keyword(s):  
Flow Stress ◽  
Constitutive Equation ◽  
Dynamic Recovery ◽  
Rate Variation ◽  
Strain Rates ◽  
Compression Tests ◽  
Temperature Range ◽  
Softening Mechanism ◽  
Dynamic Softening ◽  
Increasing Temperature

The flow stress change of 3Cr1Mo0.25V steel was researched in this paper through hot compression tests performed in a temperature range from 800 to 900oC and with a strain rate variation from 0.01 to 10s-1. Flow stress constitutive equation was constructed according to true stress-strain curves of 3Cr1Mo0.25V steel. Results indicate that the dynamic recovery is the dynamic softening mechanism of 3Cr1Mo0.25V steel. The flow stress increases with increasing strain rates and decreases with increasing temperature. The rheological behavior of 3Cr1Mo0.25V steel can be characterized by the parameter of Zener-Hollomon in a high temperature range. As for 3Cr1Mo0.25V steel, the activation energy of Q evaluated by the linear regression is about 142.9 kJ/mol.

Constitutive and Processing Map Analyses of Stainless Steel 316 under Hot Compression

2013 ◽  
Vol 378 ◽  
pp. 178-183
Author(s):  
Chui Hung Chiu ◽  
Horng Yu Wu ◽  
Cheng Tao Wu
Keyword(s):  
Stainless Steel ◽  
Flow Stress ◽  
Constitutive Equation ◽  
Strain Rate ◽  
Power Dissipation ◽  
Hot Deformation ◽  
Processing Map ◽  
Constitutive Law ◽  
Hyperbolic Sine ◽  
Stainless Steel 316

Hot deformation characteristics of stainless steel 316 were investigated at elevated temperatures. Hot compressive tests were carried out in the temperature and strain rate ranges from 800 to 1100 °C and 0.001 to 1 s1, respectively. The flow behaviors showed that the softening mechanisms were related to the dynamic recovery (DRV) and dynamic recrystallization (DRX). The constitutive equation relating flow stress, temperature, and strain rate was obtained based on the peak stress. Constitutive equation was constructed according to the hyperbolic sine constitutive law. The flow stress of stainless steel 316 was fitted well by the constitutive equation of the hyperbolic sine function. The constitutive analysis suggested that the hot deformation mechanism of the stainless steel was dislocation creep. The processing map obtained at a strain of 0.5 exhibited two domains with local maximum efficiency of power dissipation. Variation in efficiency of power dissipation was associated with the variation in ZenerHollomon parameter (Z).

Flow Behavior and Workability of a Zn-8Cu-0.2Cr Alloy during Hot Deformation

2012 ◽  
Vol 538-541 ◽  
pp. 1257-1261
Author(s):  
Sheng Li Guo ◽  
Peng Du ◽  
Xiao Ping Wu ◽  
De Fu Li
Keyword(s):  
Constitutive Equation ◽  
Strain Rate ◽  
Hot Deformation ◽  
Flow Instability ◽  
Flow Behavior ◽  
Strain Rate Range ◽  
Processing Maps ◽  
Compression Tests ◽  
Rate Range ◽  
Temperature Range

The hot deformation behavior of Zn91.8-Cu8-Cr0.2 (in wt.%) was investigated by means of hot compression tests in the temperature range of 230-380 °C and strain rate range of 0.01 - 10 s-1. The constitutive equation and processing maps were developed. The influence of strain on the flow stress was studied by considering the effect of the strain on material constants. The stress-strain curves obtained by the constitutive equation are in good agreement with experimental results. The proposed constitutive equations can be used for the analysis problem of hot forming processes. The processing maps have exhibited a domain, which is optimum processing window for hot working, in the temperature range of 310 - 380 °C and strain rate range of 0.01-1 s-1 corresponding to the higher efficiency of power dissipation. The large regime of flow instability is observed at high strain rate. The instability regime should be avoided during hot deformation processing.

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.

Analysis of Hot Deformation Dynamics of TC18 Titanium Alloy

2013 ◽  
Vol 747-748 ◽  
pp. 878-884 ◽  
Author(s):  
Qing Rui Wang ◽  
Ai Xue Sha ◽  
Xing Wu Li ◽  
Li Jun Huang
Keyword(s):  
Titanium Alloy ◽  
Phase Transformation ◽  
Flow Stress ◽  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Temperature ◽  
Relationship Model ◽  
Deformation Dynamics ◽  
Deformation Mechanics ◽  
Versus Strain

The effect of strain rate and deformation temperature on flow stress of TC18 titanium alloy was studied through heat simulating tests in 760~960 with temperature interval and the strain rate interval in 0.01~10s-1. Relationship model of flow stress versus strain was established and hot deformation mechanics of TC18 titanium alloy was analyzed. The results show that the flow stress reduces obviously as the deformation temperature increases or the strain rate decreases. Dynamic recovery occurs at high strain rate above phase transformation point, while dynamic recrystallization occurs at low strain rate as well as at the temperature below phase transformation point.

Hot working of SP-700 titanium alloy with lamellar α + β starting structure using a processing map

2020 ◽  
Vol 111 (4) ◽  
pp. 297-306
Author(s):  
Amir Hosein Sheikhali ◽  
Maryam Morakkabati
Keyword(s):  
Titanium Alloy ◽  
Strain Rate ◽  
Hot Deformation ◽  
Processing Map ◽  
Microstructural Analysis ◽  
Shear Bands ◽  
Alpha Phase ◽  
Strain Rates ◽  
Compression Tests ◽  
Temperature Range

Abstract In this study, hot deformation behavior of SP-700 titanium alloy was investigated by hot compression tests in the temperature range of 700-9508C and at strain rates of 0.001, 0.1, and 1 s-1. Final mechanical properties of the alloy (hot compressed at different strain rates and temperatures) were investigated using a shear punch testing method at room temperature. The flow curves of the alloy indicated that the yield point phenomenon occurs in the temperature range of 800- 9508C and strain rates of 0.1 and 1 s-1. The microstructural analysis showed that dynamic globularization of the lamellar α phase starts at 7008C and completes at 8008C. The alpha phase was completely eliminated from b matrix due to deformation- induced transformation at 8508C. The microstructure of specimens compressed at 8508C and strain rates of 0.001 and 0.1 s-1showed the serration of beta grain boundaries, whereas partial dynamic recrystallization caused a necklace structure by increasing strain rate up to 1 s-1. The specimen deformed at 7008C and strain rate of 1 s-1was located in the instability region and localized shear bands formed due to the low thermal conductivity of the alloy. The processing map of the alloy exhibited a peak efficiency domain of 54% in the temperature range of 780-8108C and strain rates of 0.001- 0.008 s-1. The hot deformation activation energy of the alloy in the α/β region (305.5 kJ mol-1) was higher than that in the single-phase β region (165.2 kJ mol-1) due to the dynamic globularization of the lamellar a phase.

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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