Microstructure evolution during deformation of a near-α titanium alloy with different initial structures in the two-phase region

2009 ◽  
Vol 61 (4) ◽  
pp. 419-422 ◽  
Author(s):  
Behrang Poorganji ◽  
Makoto Yamaguchi ◽  
Yoshio Itsumi ◽  
Katsushi Matsumoto ◽  
Tomofumi Tanaka ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Microstructure Evolution ◽  
Phase Region ◽  
Two Phase

scholarly journals The High-Temperature Deformation Behavior of As-Cast Ti90 Titanium Alloy

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1630
Author(s):  
Ke Wang ◽  
Yongqing Zhao ◽  
Weiju Jia ◽  
Silan Li ◽  
Chengliang Mao
Keyword(s):  
Titanium Alloy ◽  
Deformation Behavior ◽  
Processing Map ◽  
Electron Backscatter Diffraction ◽  
Phase Region ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Two Phase ◽  
Temperature Range ◽  
Β Phase

Isothermal compressions of as-cast near-α Ti90 titanium alloy were carried out on a Gleeble-3800 simulator in the temperature range of 860–1040 °C and strain rates of 0.001–10 s−1. The deformation behavior of the alloy was characterized based on the analyses of flow curves, the constructions of Arrhenius constitutive equations and the processing map. The microstructure evolution of the alloy was analyzed using the optical microscopic (OM), transmission electron microscope (TEM), and electron backscatter diffraction (EBSD) techniques. The results show that the kinking and dynamic globularization of α lamellae is the dominant mechanism of flow softening in the α + β two-phase region, while the dynamic recovery (DRV) of β phase is the main softening mechanism in the β single-phase region. The dynamic globularization of α lamellae is mainly caused by the wedging of β phase into α laths and the shearing of α laths due to imposed shear strain. The activation of prismatic and pyramidal slip is found to be easier than that of basic slip during the deformation in the α + β two-phase region. In addition, the Schmid factor of equiaxial α is different from that of lamellar α, which also varies with the angle between its geometric orientation and compression direction (CD). Based on the processing map, the low η region within the temperature range of 860–918 °C with a strain rate range of 0.318–10 s−1 should be avoided to prevent the occurrence of deformation instability.

Submicrocrystalline Structure Formation in Ti and Ti-64 Alloy by Warm “abc” Deformation

2007 ◽  
Vol 551-552 ◽  
pp. 183-188 ◽  
Author(s):  
Sergey V. Zherebtsov ◽  
Sergey Mironov ◽  
Gennady A. Salishchev
Keyword(s):  
Grain Size ◽  
Titanium Alloy ◽  
Steady State ◽  
Mechanical Behavior ◽  
Structure Formation ◽  
Microstructure Evolution ◽  
Superplastic Flow ◽  
Steady State Flow ◽  
Two Phase ◽  
State Flow

Mechanical behavior and microstructure evolution of Ti and Ti-64 titanium alloy during warm “abc” deformation has been studied. The “abc” deformation was consisted of successive compression of a sample along three orthogonal directions. Mechanical behavior of each material was described by set of successive σ-ε curves combined into cumulative σ-Σε curve. Microstructure of Ti was found to be refined to a grain size of about 0.4 μm due to formation of deformation-induced boundaries within initial grains. Although a stage like steady state flow was observed at the cumulative σ-Σε curve such mechanical behavior was hardly associated with superplastic flow. In two-phase Ti-64 alloy the structure was found to be refined to a grain size of about 0.4 μm after warm “abc” deformation due to globularization α- and β-particles following breaking down of α-lamellar and β- layers. Microstructure refinement of the alloy was associated with softening and superplastic flow.

Effect of Two-Phase Region Quenching Temperature on Microstructure Evolution and Microhardness of HSLA100 Steel

2012 ◽  
Vol 602-604 ◽  
pp. 380-384
Author(s):  
X. Yan ◽  
G.F. Zhou ◽  
C.M. Zhu ◽  
J.S. Guan
Keyword(s):  
Microstructure Evolution ◽  
Volume Fraction ◽  
High Strength ◽  
Phase Region ◽  
Two Phase ◽  
Quenching Temperature ◽  
Island Structure ◽  
Transmission Electron ◽  
Evolution Characteristics ◽  
Lath Bainite

The microstructure evolution characteristics and those effects on microhardness of HSLA (high strength low alloy) 100 steel secondary quenched in the two-phase region were investigated. The results show that the mixed microstructure of ferrite and the M-A（mastenite-austenite）islands can be obtained in the intercritical quenching region. A small amount of island structure distributing along the lath ferrite quenched at 700°C is observed by transmission electron microscope (TEM). With the quenching temperature increasing, the island structure increases in quantity and coarsens in shape, at the same time, the ferrite gradually transform from single lath morphology to polygonal shape with the dislocation density lowing. When quenched at 820°C, the microstructure reverts to lath bainite. There is a good correlation between Vickers hardness value and the volume fraction of martensite or bainite HSLA100 steel quenched in the two-phase region. The microhardness value of the steel continually increase from 240HV to 320HV quenched at the range of 700°C to 820°C, and then keep a very small fluctuation around 320HV when the temperature exceeds to 820°C.

scholarly journals Deformation and Phase Transformation of Disorder α Phase at (α+γ) two Phase Region in high Nb Containing TiAl alloy

2021 ◽  
Author(s):  
Haitao Zhou ◽  
Fantao Kong ◽  
Yanbo Wang ◽  
Xiangwu Hou ◽  
Ning Cui ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Microstructural Evolution ◽  
Microstructure Evolution ◽  
Tial Alloy ◽  
Temperature Drop ◽  
Alpha Phase ◽  
Phase Region ◽  
Two Phase ◽  
Α Phase ◽  
Assisted Decomposition

In this paper, the deformation and phase transformation of disorder α phase at (α + γ) two phase region in as-forged Ti-44Al-8Nb-(W, B, Y) alloy are investigated by hot compression and hot packed rolling. Detailed microstructural evolution demonstrates that the as-deformed microstructure is significantly affected by deformation conditions. The mircrostructure differences are mainly due to temperature drop and strain rate. The evolution of α lamelae into α grains is detailed descripted. Moreover, the disorder α lamellae can also be decomposed into some new α grains by the assisted decomposition mechanism of γ grains. Microstructure evolution model of current TiAl alloy at 1250 °C during hot rolling is built.

Experimental Study on Heat Yreatment Processing of a New Low Cost Titanium Alloy Used in Aviation Field

2013 ◽  
Vol 747-748 ◽  
pp. 919-925 ◽  
Author(s):  
Guo Qiang Shang ◽  
Xin Nan Wang ◽  
Yue Fei ◽  
Jun Li ◽  
Zhi Shou Zhu ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Low Cost ◽  
Solution Treatment ◽  
Heat Treating ◽  
Optical Microscope ◽  
Phase Region ◽  
Solution Temperature ◽  
Two Phase ◽  
Common Solution ◽  
Strength And Plasticity

The effect of common solution treatment, two-step solution treatment and aging, solution treatment and aging (STA) on the microstructure and mechanical properties of a new low cost titanium alloy used in aviation field were investigated by optical microscope (OM), scanning electron microscopy (SEM) and tensile test. The results show that a typical equiaxed structure can be obtained by common solution treatment leading to a good combination of strength and plasticity. Besides, solution heat treating in the β region and subsequently ageing at a low temperature results in a significant increase in mechanical strength and a little decrease in plasticity. When the solution temperature is at α+β two-phase region (895), the low cost titanium alloy acquires the best combination of strength and ductility.

scholarly journals Numerical and Experimental Study on Microstructure Evolution of Ti-6Al-4V Alloy Shaft Perform in Cross-Wedge Rolling Process

2021 ◽  
Author(s):  
Jiayao Yuan ◽  
Xing Chen ◽  
Zhilong Zhao ◽  
Baoshou Sun ◽  
Xuedao Shu
Keyword(s):  
Grain Size ◽  
Microstructure Evolution ◽  
Phase Region ◽  
Rolling Temperature ◽  
Structure Evolution ◽  
Cross Wedge Rolling ◽  
Two Phase ◽  
Rotating Speed ◽  
Area Reduction ◽  
Average Grain Size

Abstract To seek a fundamental understanding for further improving the Ti-6Al-4V alloy utilization of Cross-Wedge Rolling (CWR) and the comprehensive mechanical properties of shaft parts, the effect of the CWR processing parameters on the microstructure evolution of Ti-6Al-4V alloy shaft preform is studied in this paper. An Arrhenius-type microstructure structure evolution model was employed and implemented into the finite element software DEFORM-3D. The average grain size and dynamic re-crystallization volume fraction distribution in the α+β two-phase region and the β single phase region under different rolling temperature, roller rotating speed and area reduction were analyzed, respectively. It is finding that the area reduction, rolling temperature and roller rotating speed significantly affect the microstructure evolution of Ti-6Al-4V alloy. Meanwhile, the corresponding CWR and Metallographic experiments were conducted to verify the reliability of the FE simulation results. Results showed that the agreement of the process parameters effect on dynamic recrystallization in the α+β two-phase region between simulation and experimental is reasonably good. The difference in average grain size in the β phase region between simulation and experimental is ranged from 5.77% to 18.56%. In addition, the evenly distributed microstructure can be found as the area reduction of 50%, rolling temperature of 950℃ and the speed of 5 r⋅min−1 were employed. After rolling under optimized processing conditions, the tensile strength of Ti-6Al-4V alloy shaft preform increased by 18.57% and the plasticity enhanced significantly due to smaller grain size and bi-model microstructure obtained.

scholarly journals Dynamic Recrystallization Behavior of TA15 Titanium Alloy under Isothermal Compression during Hot Deformation

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Yuanxin Luo ◽  
Yuqing Heng ◽  
Yongqin Wang ◽  
Xingchun Yan
Keyword(s):  
Titanium Alloy ◽  
Dynamic Recrystallization ◽  
Dimensionless Parameter ◽  
Volume Fraction ◽  
Phase Region ◽  
Two Phase ◽  
Ta15 Titanium Alloy ◽  
Dynamic Recrystallization Behavior ◽  
Series Of Experiments ◽  
Sine Equation

In order to improve the understanding of the dynamic recrystallization (DRX) behaviors of TA15 titanium alloy (Ti-6Al-2Zr-1Mo-1V), a series of experiments were conducted on a TMTS thermal simulator at temperatures of 1173 K, 1203 K, 1223 K, and 1273 K with the strain rates of 0.005 s−1, 0.05 s−1, 0.5 s−1, and 1 s−1. By the regression analysis for conventional hyperbolic sine equation, the activation energy of DRX inα+βtwo-phase region isQS=588.7 Kg/moland inβregion isQD=225.8 Kg/mol, and a dimensionless parameter controlling the stored energy was determined asZ/A=ε˙exp(588.7×103)/RT/6.69×1026inα+βtwo-phase region and asZ/A=ε˙exp(225.8×103)/RT/5.13×1011inβregion. The DRX behaviors of TA15 titanium alloy were proposed on the strength of the experiment results. Finally, the theoretical prediction results of DRX volume fraction were shown to be in agreement with experimental observations.

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