scholarly journals Texture evolution during Isothermal compression process of Ti-22Al-25Nb alloy in B2 phase region

2020 ◽  
Vol 321 ◽  
pp. 12036
Author(s):  
Haoyuan Ma ◽  
Weidong Zeng ◽  
Xiongxiong Gao ◽  
Youping Zheng
Keyword(s):  
Dynamic Recrystallization ◽  
Hot Deformation ◽  
Dynamic Recovery ◽  
Texture Evolution ◽  
Phase Region ◽  
Fiber Axis ◽  
Isothermal Compression ◽  
Compression Process ◽  
Compression Direction ◽  
Grain Orientations

In the present work, the hot deformation behavior, dynamic recovery, dynamic recrystallization and texture evolution of Ti-22Al-25Nb alloy on the conditions of 1100°C with four different thickness reductions (35%, 50%, 65% and 80%) are investigated by isothermal compression testing on Gleeble-3500 thermo-mechanical simulator. The strain rate is 0.1mm/s-1. Subsequently, metallographic observation and EBSD analysis are carried out. The results show that during the hot deformation, the dynamic recovery (DRV) and dynamic recrystallization (DRX) strongly affect the microstructure and texture evolution. It is observed that with the strain increasing, the intensity of ηbcc-fiber increases firstly (crystallographic fiber axis <100> parallel to the compression direction). When the thickness reduction reaches to 80%, the intensity of <001> pole becomes stronger expectedly. Whereas the ηbcc-fiber transform into cube components ({100} <001>) unexpectedly. In addition, as the strain increases through 35%-80%, the fraction of large misorientation grain boundaries and fraction of DRX grains gradually increase due to continuous recrystallization. The evolution mechanism of grain orientations and texture during the DRX process will be discussed.

scholarly journals Effect of Supra-Transus Deformation Conditions on Recrystallization of Beta Ti Alloy

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1278
Author(s):  
Chao Voon Samuel Lim ◽  
Yang Liu ◽  
Chen Ding ◽  
Aijun Huang
Keyword(s):  
Hot Deformation ◽  
Static Recrystallization ◽  
Dynamic Recovery ◽  
Texture Evolution ◽  
High Strength ◽  
Ex Situ ◽  
Mechanical Processing ◽  
Ti Alloy ◽  
Electron Backscattered Diffraction ◽  
Beta Ti Alloy

There is increasing usage of high strength Beta Ti alloy in aerospace components. However, one of the major challenges is to obtain homogeneous refined microstructures via the thermo-mechanical processing. To overcome this issue, an understanding of the hot deformation conditions effect on the microstructure, prior to and after annealing, is needed. In this work, the effect of strain levels, which is more precise than percentage of reduction, and strain rate under supra-transus deformation temperature on beta annealing are studied using a double cone sample. The Electron Backscattered Diffraction (EBSD) is used to determine the deformed microstructure and texture evolution, as well as the static recrystallized grains evolution using the ex situ annealing approach. This work provides evidence that the mechanisms of dynamic recovery and recrystallization, along with texture evolution, are affected by the deformation conditions, which in turn affected the subsequent static recrystallization during annealing. It will also be shown that high levels of strain do not necessarily lead to an increase in the rate of recrystallization. Finally, the results obtained provided several examples of guidance in designing the TMP processes for obtaining not only a refine microstructure, but a more homogeneous beta microstructure during the beta processing of Beta Ti alloy.

scholarly journals High-Temperature Deformation Behavior and Microstructural Characterization of Ti-35421 Titanium Alloy

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3623 ◽  
Author(s):  
Danying Zhou ◽  
Hua Gao ◽  
Yanhua Guo ◽  
Ying Wang ◽  
Yuecheng Dong ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Deformation Temperature ◽  
Phase Region ◽  
Temperature Deformation ◽  
Β Phase ◽  
Α Phase

A self-designed Ti-35421 (Ti-3Al-5Mo-4Cr-2Zr-1Fe wt%) titanium alloy is a new type of low-cost high strength titanium alloy. In order to understand the hot deformation behavior of Ti-35421 alloy, isothermal compression tests were carried out under a deformation temperature range of 750–930 °C with a strain rate range of 0.01–10 s−1 in this study. Electron backscatter diffraction (EBSD) was used to characterize the microstructure prior to and post hot deformation. The results show that the stress–strain curves have obvious yielding behavior at a high strain rate (>0.1 s−1). As the deformation temperature increases and the strain rate decreases, the α phase content gradually decreases in the α + β phase region. Meanwhile, spheroidization and precipitation of α phase are prone to occur in the α + β phase region. From the EBSD analysis, the volume fraction of recrystallized grains was very low, so dynamic recovery (DRV) is the dominant deformation mechanism of Ti-35421 alloy. In addition to DRV, Ti-35421 alloy is more likely to occur in continuous dynamic recrystallization (CDRX) than discontinuous dynamic recrystallization (DDRX).

scholarly journals Study of the Dynamic Recrystallization Process of the Inconel625 Alloy at a High Strain Rate

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 510 ◽  
Author(s):  
Zhi Jia ◽  
Zexi Gao ◽  
Jinjin Ji ◽  
Dexue Liu ◽  
Tingbiao Guo ◽  
...  
Keyword(s):  
Dynamic Recrystallization ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Volume Fraction ◽  
Electron Backscatter Diffraction ◽  
Texture Evolution ◽  
True Strain ◽  
Recrystallization Process ◽  
Compression Process

High-temperature compression and electron backscatter diffraction (EBSD) techniques were used in a systematic investigation of the dynamic recrystallization (DRX) behavior and texture evolution of the Inconel625 alloy. The true stress–true strain curves and the constitutive equation of Inconel625 were obtained at temperatures ranging from 900 to 1200 °C and strain rates of 10, 1, 0.1, and 0.01 s−1. The adiabatic heating effect was observed during the hot compression process. At a high strain rate, as the temperature increased, the grains initially refined and then grew, and the proportion of high-angle grain boundaries increased. The volume fraction of the dynamic recrystallization increased. Most of the grains were randomly distributed and the proportion of recrystallized texture components first increased and then decreased. Complete dynamic recrystallization occurred at 1100 °C, where the recrystallized volume fraction and the random distribution ratios of grains reached a maximum. This study indicated that the dynamic recrystallization mechanism of the Inconel625 alloy at a high strain rate included continuous dynamic recrystallization with subgrain merging and rotation, and discontinuous dynamic recrystallization with bulging grain boundary induced by twinning. The latter mechanism was less dominant.

Effect of β Annealing and near β Zone Hot Deformation on the Microstructure and Texture of TC18 Alloy

2016 ◽  
Vol 849 ◽  
pp. 226-231
Author(s):  
Yi Min Cui ◽  
Wei Wei Zheng ◽  
Feng Zhang ◽  
Ai Xue Sha
Keyword(s):  
Grain Boundary ◽  
Dynamic Recrystallization ◽  
Small Angle ◽  
Hot Deformation ◽  
Static Recrystallization ◽  
Dynamic Recovery ◽  
Fiber Texture ◽  
Dual Phase ◽  
Phase Zone ◽  
Β Phase

Forged TC18 alloy billets with strong <100> texture were selected to investigate the effects of β annealing and near β zone hot deformation on the microstructure and texture by means of optical microscopy, XRD and EBSD techniques. The results showed that the original <100> fiber texture can’t be eliminated through β annealing although completed static recrystallization happened during annealing. After deforming in near β phase zone, the microstructures were composed of elongated β grains. A lot of small angle boundaries were observed near the original β grain boundaries, indicating that dynamic recovery controlled the deformation. Dynamic recrystallization grains can only be seen at the original β grain boundary at the strain of 50%. <100>//TD and <111>//TD texture were generated during the near β zone hot deformation. Annealing at dual phase zone after hot deformation can effectively reduce the proportion of grains with <111> orientation, but the <100>//TD texture still existed.

Flow behavior and microstructure evolution of PM Ti-5553 alloy during 0.1 s−1 hot deformation

2019 ◽  
Vol 34 (01n03) ◽  
pp. 2040026
Author(s):  
Qinyang Zhao ◽  
Fei Yang ◽  
Rob Torrens ◽  
Leandro Bolzoni
Keyword(s):  
Hot Deformation ◽  
Deformation Behavior ◽  
Dynamic Recovery ◽  
Flow Behavior ◽  
Intermediate Strain Rate ◽  
Isothermal Compression ◽  
Flow Localization ◽  
Hot Deformation Behavior ◽  
Deformation Degree ◽  
Dynamic Morphology

The hot deformation behavior of powder metallurgy Ti-5Al-5V-5Mo-3Cr (Ti-5553) alloy was investigated by isothermal compression test at the wide temperature range of [Formula: see text]–[Formula: see text]C, under an intermediate strain rate of 0.1 s[Formula: see text], and with the sample deformation degree of 30%, 50% and 70%. Results suggested that the flow stress was very sensitive to the deformation variables and it decreased with increasing the deformation temperature. Flow localization occurred when the temperature was lower than [Formula: see text]C, accompanied by the dynamic morphology changing of [Formula: see text] phase. Dynamic recovery (DRV) features appeared when the temperature was over [Formula: see text]C, while dynamic recrystallization (DRX) took a more important role than DRV for the alloy compressed at [Formula: see text]–[Formula: see text]C.

Research on Superplastic Forming of Supplied LY12 Aluminum Alloy for Fishing Spools

2007 ◽  
Vol 551-552 ◽  
pp. 245-248
Author(s):  
Yong Shun Yang ◽  
Guo Qing Chen ◽  
X. Yang
Keyword(s):  
Dynamic Recrystallization ◽  
Grain Refinement ◽  
Early Stage ◽  
Superplastic Forming ◽  
Service Performance ◽  
Isothermal Compression ◽  
Compression Process ◽  
High Deformation ◽  
Process Dynamic ◽  
Deformation Speed

The superplasticity of LY12 alloy was reviewed in this paper. Complex component was extruded by taking advantage of the superplasticity of supplied LY12 alloy. The research demonstrates that in isothermal compression process dynamic recrystallization may occur in supplied LY12 alloy. In superplastic forming test grain refinement was combined with initial extrusion step utilizing dynamic recrystallization to complete grain refinement, which ensured the superplasticity in supplied LY12. In the early stage of extrusion, using high deformation speed and large amount of deformation can result in grain refinement, which primarily satisfied the demand of the superplasticity. In the final stage, the forming speed decreased sharply so that the optimum strain rate was satisfied and the complicated component can be extruded successfully. The resulted product has reasonable flowing traces, which improves its service performance.

Dynamic Recrystallization of Ferrite in a Low Carbon Nb-Microalloyed Steel

2005 ◽  
Vol 475-479 ◽  
pp. 149-152 ◽  
Author(s):  
Long Fei Li ◽  
Wang Yue Yang ◽  
Zu Qing Sun
Keyword(s):  
Dynamic Recrystallization ◽  
Hot Deformation ◽  
Microalloyed Steel ◽  
Phase Region ◽  
Ferrite Phase ◽  
Recrystallization Process ◽  
Low Carbon ◽  
Promoting Effect ◽  
Nb Microalloyed Steel ◽  
Average Size

The hot deformation behavior of a low carbon Nb-microalloyed steel is investigated by hot compression test in the ferrite phase region compared with a low carbon steel with similar compositions, and the effect of Nb on dynamic recrystallization of ferrite is analyzed. Results indicate that during hot deformation in the ferrite phase region, the effect of Nb solely depends on the size of NbC precipitates. Tiny particles which average size is about 7.5nm have a retarding effect on dynamic recrystallization process of ferrite, on the contrary, coarser particles which average size is about 30.6nm have a promoting effect and are of benefit to the refinement of recrystallized grains.

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