Dynamic softening behavior of TC18 titanium alloy during hot deformation

AbstractIn order to investigate the effect of dynamic recrystallization (DRX) behavior on dynamic softening behavior of wrought Ti-10V-2Fe-3Al titanium alloy, a series of laboratory scale isothermal hot compression tests with a height reduction of 60% were performed in a temperature range of 948 K~1023 K in the (

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Effect of Equal Channel Angular Pressing on the Dynamic Softening Behavior of Ti-6Al-4V Alloy in the Hot Deformation Process

Materials ◽

10.3390/ma14010232 ◽

2021 ◽

Vol 14 (1) ◽

pp. 232

Author(s):

Zhiyong Zhao ◽

Jun Gao ◽

Yaoqi Wang ◽

Yanling Zhang ◽

Hongliang Hou

Keyword(s):

Dynamic Recrystallization ◽

Strain Rate ◽

Equal Channel Angular Pressing ◽

Hot Deformation ◽

Deformation Process ◽

Hot Compression ◽

Deformation Condition ◽

Softening Behavior ◽

Angular Pressing ◽

Dynamic Softening

To investigate the effect of equal channel angular pressing (ECAP) on the deformation of Ti-6Al-4V alloy at a higher temperature, hot compression tests were conducted on alloys having two different initial microstructures (the original alloy (Pre-ECAP) and ECAP-deformed alloy (Post-ECAP)). Post-ECAP, the alloy showed a higher degree of dynamic softening during the hot deformation process due to its finer grain size and higher distortion energy. The flow stress of Post-ECAP alloy was higher than the Pre-ECAP alloy at 500 °C when ε˙= 0.003 s−1. However, the stress of the Post-ECAP alloy decreased rapidly with increasing temperature and strain rate, until the stress value was much lower than that of Pre-ECAP at 700 °C when ε˙= 0.03 s−1. The value of the dynamic softening coefficient revealed that the dynamic softening behavior of Post-ECAP was more pronounced than that of Pre-ECAP in the hot compression deformation process. The main dynamic softening mechanism of Pre-ECAP is dynamic recovery, while the dynamic recrystallization process plays a more important role in the deformation process of Post-ECAP alloy. The microstructures observation results showed that dynamic recrystallization was more likely to occur to Post-ECAP alloys under the same deformation condition. Almost fully dynamic recrystallization had occurred in the deformation process of Post-ECAP at 700 °C and a strain rate of ε˙= 0.01 s−1. The grains of Post-ECAP alloys were further refined. The Post-ECAP alloy exhibits better plastic deformation at temperatures higher than 600 °C due to its significant dynamic recrystallization.

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Dynamic softening behavior and microstructural characterization of TiAl-based alloy during hot deformation

Materials Characterization ◽

10.1016/j.matchar.2017.05.022 ◽

2017 ◽

Vol 130 ◽

pp. 25-32 ◽

Cited By ~ 15

Author(s):

Zhipeng Wan ◽

Yu Sun ◽

Lianxi Hu ◽

Huan Yu

Keyword(s):

Hot Deformation ◽

Microstructural Characterization ◽

Softening Behavior ◽

Dynamic Softening

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Dynamic Softening and Hardening Behavior and the Micro-Mechanism of a TC31 High Temperature Titanium Alloy Sheet within Hot Deformation

Materials ◽

10.3390/ma14216515 ◽

2021 ◽

Vol 14 (21) ◽

pp. 6515

Author(s):

Kexin Dang ◽

Kehuan Wang ◽

Gang Liu

Keyword(s):

Titanium Alloy ◽

High Temperature ◽

Dynamic Recrystallization ◽

Strain Rate ◽

Hot Deformation ◽

Deformation Temperature ◽

Tensile Deformation ◽

Alloy Sheet ◽

Dynamic Softening ◽

Thin Walled

TC31 is a new type of α+β dual phase high temperature titanium alloy, which has a high specific strength and creep resistance at temperatures from 650 °C to 700 °C. It has become one of the competitive candidates for the skin and air inlet components of hypersonic aircraft. However, it is very difficult to obtain the best forming windows for TC31 and to form the corresponding complex thin-walled components. In this paper, high temperature tensile tests were carried out at temperatures ranging from 850 °C to 1000 °C and strain rates ranging from 0.001 s−1 to 0.1 s−1, and the microstructures before and after deformation were characterized by an optical microscope, scanning electron microscope, and electron back-scatter diffraction. The dynamic softening and hardening behaviors and the corresponding micro-mechanisms of a TC31 titanium alloy sheet within hot deformation were systematically studied. The effects of deformation temperature, strain rate, and strain on microstructure evolution were revealed. The results show that the dynamic softening and hardening of the material depended on the deformation temperature and strain rate, and changed dynamically with the strain. Obvious softening occurred during hot tensile deformation at a temperature of 850 °C and a strain rate of 0.001 s−1~0.1 s−1, which was mainly caused by void damage, deformation heat, and dynamic recrystallization. Quasi-steady flowing was observed when it was deformed at a temperature of 950 °C~1000 °C and a strain rate of 0.001 s−1~0.01 s−1 due to the relative balance between the dynamic softening and hardening. Dynamic hardening occurred slightly with a strain rate of 0.001 s−1. Mechanisms of dynamic recrystallization transformed from continuous dynamic recrystallization to discontinuous dynamic recrystallization with the increase in strain when it was deformed at a temperature of 950 °C and a strain rate of 0.01 s−1. The grain size also decreased gradually due to the dynamic recrystallization, which provided an optimal forming condition for manufacturing thin-walled components with the desired microstructure and an excellent performance.

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

Metals ◽

10.3390/met11050789 ◽

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.

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

Materials ◽

10.3390/ma14092456 ◽

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.

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The Effect of α-Al(MnCr)Si Dispersoids on Activation Energy and Workability of Al-Mg-Si-Cu Alloys during Hot Deformation

Advances in Materials Science and Engineering ◽

10.1155/2020/3471410 ◽

2020 ◽

Vol 2020 ◽

pp. 1-12

Author(s):

Xiaoguo Wang ◽

Jian Qin ◽

Hiromi Nagaumi ◽

Ruirui Wu ◽

Qiushu Li

Keyword(s):

Activation Energy ◽

Aluminum Alloys ◽

Constitutive Equation ◽

Hot Deformation ◽

Flow Instability ◽

Void Formation ◽

Activation Energies ◽

Compression Tests ◽

Softening Mechanism ◽

Dynamic Softening

The hot deformation behaviors of homogenized direct-chill (DC) casting 6061 aluminum alloys and Mn/Cr-containing aluminum alloys denoted as WQ1 were studied systematically by uniaxial compression tests at various deformation temperatures and strain rates. Hot deformation behavior of WQ1 alloy was remarkably changed compared to that of 6061 alloy with the presence of α-Al(MnCr)Si dispersoids. The hyperbolic-sine constitutive equation was employed to determine the materials constants and activation energies of both studied alloys. The evolution of the activation energies of two alloys was investigated on a revised Sellars’ constitutive equation. The processing maps and activation energy maps of both alloys were also constructed to reveal deformation stable domains and optimize deformation parameters, respectively. Under the influence of α dispersoids, WQ1 alloy presented a higher activation energy, around 40 kJ/mol greater than 6061 alloy’s at the same deformation conditions. Dynamic recrystallization (DRX) is main dynamic softening mechanism in safe processing domain of 6061 alloy, while dynamic recovery (DRV) was main dynamic softening mechanism in WQ1 alloy due to pinning effect of α-Al(MnCr)Si dispersoids. α dispersoids can not only resist DRX but also increase power required for deformation of WQ1 alloy. The microstructure analysis revealed that the flow instability was attributed to the void formation and intermetallic cracking during hot deformation of both alloys.

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Analysis of Hot Deformation Dynamics of TC18 Titanium Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.747-748.878 ◽

2013 ◽

Vol 747-748 ◽

pp. 878-884 ◽

Cited By ~ 1

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.

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