scholarly journals Understanding the Role of β Recrystallization on β Microtexture Evolution in Hot Processing of a Near-β Titanium Alloy (Ti-10V-2Fe-3Al)

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1397
Author(s):  
Dayu Shu ◽  
Li Wang ◽  
Qiang Chen ◽  
Yi Yao ◽  
Minghui Li ◽  
...  
Keyword(s):  
Grain Size ◽  
Titanium Alloy ◽  
Strain Rate ◽  
Strain Rate Range ◽  
Slip Systems ◽  
Recrystallization Behavior ◽  
Β Phase ◽  
Crystal Rotation ◽  
Average Grain Size ◽  
Tb6 Titanium Alloy

The present study evaluated the β recrystallization behavior and deformation microtexture evolution of TB6 titanium alloy (Ti-10V-2Fe-3Al) taking place during isothermal compression. The hot deformation tests were carried out in the temperature range below the β phase transition temperature and spanned a wide strain rate range of 0.0001~1 s−1. Microstructure evolution on β phase, including its recrystallization behavior and microtexture formation, is sensitive to the strain rates, whereas the average grain size of equiaxed α phase exhibits a slight increase with the strain rate decreasing. Moreover, β recrystallization is not homogeneous among the prior β grains, and is characterized by: (I) enriched β sub-grains, (II) sporadically or chain-like distributed recrystallized β grains with a grain size far less than the prior β grains, and (III) wave-shaped β grain boundaries. The β recrystallization is inadequate and its orientation takes on the inheritance characteristic, which makes the β microtexture significant after deformation. At a lower strain rate, the high activity of the {11−2}<111> and {12−3}<111> slip systems induced the crystal rotation around <101>, but such crystal rotation did not destroy the Burgers orientation relationship (BOR), which could be accounted for by the generation of a strong microtexture of <001>//RD. The divergences on β recrystallization fraction, the operation of slip systems, and initial crystal orientations explain the different microtexture components with varied intensities under different deformation conditions.

Recrystallization and Grain Growth Behavior of Alloy 718 Casting during Hot Working

2007 ◽  
Vol 345-346 ◽  
pp. 57-60 ◽  
Author(s):  
Jong Won Yoon ◽  
Nam Yong Kim ◽  
Jeoung Han Kim ◽  
Jong Taek Yeom ◽  
Nho Kwang Park
Keyword(s):  
Grain Size ◽  
Strain Rate ◽  
Grain Growth ◽  
Growth Behavior ◽  
Area Fraction ◽  
Alloy 718 ◽  
Recrystallization Behavior ◽  
Temperature Range ◽  
Average Grain Size ◽  
Grain Growth Behavior

Recrystallization and grain growth behavior of alloy 718 casting were investigated to obtain homogeneous microstructure during hot forging. For this purpose, compression tests were carried out for cylindrical specimens at the temperature range of 1000 to 1150°C and the strain rate of 10-1 and 10sec-1. The dynamic recrystallization behavior caused by the hot compression was investigated in terms of the recrystallized area fraction and average grain size. Reheating was followed to the hot compressed samples at the temperature range of 1050 to 1150°C for 100, 600 and 1800sec, and the static recrystallization behavior caused by the reheating was also investigated. As hot deformation temperature increased from 1000 to 1150°C, both the area fraction and average grain size of dynamically recrystallized grains increased. When higher strain rate of 10 sec-1 was used, the area fraction of dynamically recrystallized grains increased substantially, but the average grain size was not affected. When reheating the hot compressed samples at 1050°C for 100, 600 and 1800sec, respectively, microstructural change including grain growth was not noticed. On the other hand, when reheating the samples at higher temperatures, 1100°C and 1150°C, both the area fraction and the average grain size of the statically recrystallized grains increased considerably as the holding time increased from 100 to 1800sec.

Effect of Grain Size on Deformation Twinning Behavior of Ti6Al4V Alloy

2015 ◽  
Vol 830-831 ◽  
pp. 337-340
Author(s):  
Ashish Kumar Saxena ◽  
Manikanta Anupoju ◽  
Asim Tewari ◽  
Prita Pant
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Strain Rate ◽  
Deformation Behavior ◽  
Deformation Behaviour ◽  
Air Cooling ◽  
Specific Strength ◽  
Aerospace Applications ◽  
Β Phase ◽  
Plastic Deformation Behavior

An understanding of the plastic deformation behavior of Ti6Al4V (Ti64) is of great interest because it is used in aerospace applications due to its high specific strength. In addition, Ti alloys have limited slip systems due to hexagonal crystal structure; hence twinning plays an important role in plastic deformation. The present work focuses upon the grain size effect on plastic deformation behaviour of Ti64. Various microstructures with different grain size were developed via annealing of Ti64 alloy in α-β phase regime (825°C and 850°C) for 4 hours followed by air cooling. The deformation behavior of these samples was investigated at various deformation temperature and strain rate conditions. Detailed microstructure studies showed that (i) smaller grains undergoes twinning only at low temperature and high strain rate, (ii) large grain samples undergo twinning at all temperatures & strain rates, though the extent of twinning varied.

Superplastic Behavior of a Cu-Cr-Zr Alloy Subjected to ECAP

2016 ◽  
Vol 838-839 ◽  
pp. 404-409
Author(s):  
Roman Mishnev ◽  
Iaroslava Shakhova ◽  
Andrey Belyakov ◽  
Rustam Kaibyshev
Keyword(s):  
Grain Size ◽  
Dislocation Density ◽  
Strain Rate ◽  
Temperature Interval ◽  
Rate Sensitivity ◽  
Tensile Tests ◽  
Superplastic Behavior ◽  
Average Grain Size ◽  
Gauge Section ◽  
Zr Alloy

A Cu-0.87%Cr-0.06%Zr alloy was subjected to equal channel angular pressing (ECAP) at a temperature of 400 °C up to a total strain of ~ 12. This processing produced ultra-fine grained (UFG) structure with an average grain size of 0.6 μm and an average dislocation density of ~4×1014 m-2. Tensile tests were carried out in the temperature interval 450 – 650 °C at strain rates ranging from 2.8´10-4 to 0.55 s-1. The alloy exhibits superplastic behavior in the temperature interval 550 – 600 °C at strain rate over 5.5´10-3 s-1. The highest elongation-to-failure of ~300% was obtained at a temperature of 575 °C and a strain rate of 2.8´10-3 s-1 with the corresponding strain rate sensitivity of 0.32. It was shown the superplastic flow at the optimum conditions leads to limited grain growth in the gauge section. The grain size increases from 0.6 μm to 0.87 μm after testing, while dislocation density decreases insignificantly to ~1014 m-2.

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).

Effect of high-power ion beams on the surface topography and structure of submicrocrystalline titanium alloy subsurface layers

2018 ◽  
pp. 82-91
Author(s):  
M. V. Zhidkov ◽  
A. E. Ligachev ◽  
Yu. R. Kolobov ◽  
G. V. Potemkin ◽  
G. E. Remnev
Keyword(s):  
Grain Size ◽  
Titanium Alloy ◽  
High Power ◽  
Ion Beam ◽  
Structural Phase ◽  
Subsurface Layer ◽  
Ion Beams ◽  
Uniform Structure ◽  
Average Grain Size ◽  
Subsurface Layers

The study covers the topography and structural phase state of VT1-0 and VT6 submicrocrystalline titanium alloy subsurface layers irradiated by high power pulsed carbon ion beams (ion energy is 250 keV, pulse duration is ~100 ns, pulse current density is 150–200 A/cm2; surface energy density of a single pulse is j ~ 3 J/cm2 when irradiating VT1-0 titanium alloy samples and j ~ 1 J/cm2 when processing VT6 titanium alloy samples; pulse number is 1, 5, 10, and 50). The surface of samples was subjected to preliminary mechanical grinding and polishing before irradiation. It was shown that surface defects are formed on the surface of the alloys after irradiation, namely craters of different shapes and geometries with a diameter from fractions of a micron to 80–100 μm. At the same time, the grain structure in the subsurface layer becomes more homogeneous in terms of grain size and equiaxial properties. The initial state of titanium alloys is characterized by a fairly homogeneous structure with an average grain size of ~0,31 μm for VT1-0 and ~0,9 μm for VT6. After one irradiation pulse, grain growth to 0,54 μm in the transverse direction is observed in the subsurface layer of the VT1-0 alloy (j ~ 3 J/cm2), while grain size decreases to ~ 0,54 μm in the VT6 alloy (j ~ 1 J/cm2). After 50 pulses, the average grain size in the subsurface layer reaches ~2,2 μm for the VT1-0 alloy and ~1,6 μm for VT6. It should be noted that a rather uniform structure with equiaxed grains is formed as early as after treating with 1 high power ion beam pulse.

Effect of Deformation Route and Sc and Zr Addition on Ultra-Fine Grain Formation and Superplasticity in Al-Mg Alloys

2006 ◽  
Vol 519-521 ◽  
pp. 847-852
Author(s):  
Suk Bong Kang ◽  
Jae Woon Kim ◽  
Hyoung Wook Kim
Keyword(s):  
Grain Size ◽  
Strain Rate ◽  
Deformation Process ◽  
Mg Alloys ◽  
Fine Grained ◽  
Loading Direction ◽  
Zr Addition ◽  
Average Grain Size ◽  
Multiple Deformation ◽  
Al Mg Alloys

Recently the method for obtaining ultra-fine grained metallic materials has developed using severe plastic deformation (SPD), such as equal channel angular pressing (ECAP), accumulative roll bonding (ARB), torsion straining, and warm multiple deformation (WMD) etc. In order to enhance thermal stability of ultra-fine grained aluminum alloys manufactured by SPD process, the addition of Sc and Zr elements has been considered to devise fine Al3Sc, Al3Zr and Al3(Scx Zr1-x) precipitates for inhibiting the grain growth. In this study, the microstructure evolution has been investigated in Al-Mg alloys with and without Sc and Zr addition during the warm multiple deformation process. In addition Al-Mg alloys were compressed at a strain rate of 10-1 sec-1 by two different routes, that is, route A and route B. Route A is to rotate the specimen throughout 90o around the vertical axis of loading direction at every pass. Route B is to rotate the specimen throughout 90o around the parallel axis of loading direction and then rotate it again as route A. The specimen deformed by route B had finer grain size and more uniform distribution of grains than those deformed by route A. When the warm multiple deformation process repeated up to 8 passes at 673 K, the specimen consisted of ultra-fine grained structure with the average grain size less than 3 μm. The superplastic behavior can also be observed at the high strain rate and low temperature regime.

Deformation Behavior and Processing Map of High Temperature of TC21 Titanium Alloy

2013 ◽  
Vol 274 ◽  
pp. 427-431 ◽  
Author(s):  
Ying Gong
Keyword(s):  
Titanium Alloy ◽  
Flow Stress ◽  
Strain Rate ◽  
Deformation Behavior ◽  
Processing Map ◽  
True Strain ◽  
Strain Rate Range ◽  
Peak Region ◽  
Working Zone ◽  
Dynamic Materials

The compression test on TC21 titanium alloy was carried out in the temperature range of 860~940oC and the strain rate range of 0.01~10s-1 on Gleeble-1500D hot simulation machine. And the hot deformation behavior was studied. The processing map was calculated and analyzed according the dynamic materials model. It is found that the flow stress of TC21 decreases with the increasing of the temperature and the decreasing of the strain rate. The flow stress curves are characterized by steady state at low strain rate( s-1）but discontinuous yield at high strain rate( s-1). The processing map established at the true strain of 0.4 shows that there are three regions, instability and safe and peak region, and the efficiencies of power dissipation are 0~25%，31%~37% and 43%~49% respectively. The peak region is the optimum hot working zone of TC21 titanium alloy.

Deformation Heating and Its Effect on the Processing Maps of Ti-15-3 Titanium Alloy

2013 ◽  
Vol 712-715 ◽  
pp. 58-64
Author(s):  
Jing Qi Zhang ◽  
Hong Shuang Di ◽  
Xiao Yu Wang
Keyword(s):  
Titanium Alloy ◽  
Strain Rate ◽  
Rate Sensitivity ◽  
Strain Rate Range ◽  
Processing Maps ◽  
Compression Tests ◽  
Temperature Range ◽  
Deformation Heating ◽  
Instability Criteria ◽  
Flow Stress Data

In the present study, deformation heating generated by plastic deformation and its effect on the processing maps of Ti-15-3 titanium alloy were investigated. For this purpose, hot compression tests were performed on a Gleeble-3800 thermo-mechanical simulator in the temperature range of 850-1150 °C and strain rate range of 0.001-10 s1. The temperature rise due to deformation heating was calculated and the as-measured flow curves were corrected for deformation heating. Using the as-measured and corrected flow stress data, the processing maps for Ti-15-3 titanium alloy at a strain of 0.5 were developed on the basis Murty‘s and Babu’s instability criteria. The results show that both the instability maps based the two instability criteria are essentially similar and are characterized by an unstable region occurring at strain rates higher than 0.1 s1for almost the entire temperature range tested. The unstable regions are overestimated from the as-measured data due to the effect of deformation heating, indicating a better workability after correcting the effect of deformation heating. This is further conformed by the analysis based on strain rate sensitivity.

Finite Element Modeling of Grain Size Effect on the Mechanical Properties and Deformability of Titanium Alloy in Equal Channel Angular Pressure

2015 ◽  
Vol 661 ◽  
pp. 91-97
Author(s):  
Cho-Pei Jiang ◽  
Zong Han Huang
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Finite Element ◽  
Titanium Alloy ◽  
Tensile Test ◽  
Annealing Treatment ◽  
Cross Sectional ◽  
Squeeze Pressure ◽  
Brittle Behavior ◽  
Β Phase

The aim of this research is to investigate the effect of grain size on the mechanical properties and deformability of titanium alloy in equal channel and cross-sectional reduction channel angular pressing process. Specimens made of grade 2 titanium alloy with diameter 5 mm are annealed to temperature of 500 °C to 1000 °C resulting in different initial grain sizes, thus underwent tensile test for obtaining mechanical properties. Molds for both processes are designed to carry out serve plastic deformation. Finite element models are created and simulated the deformation behavior according to the mechanical properties of tensile test. Experimental results show that small α-phase grain starts to form in 700 °C homogenization treatment and its grain size increases as an increasing of annealing temperature. The β-phase microstructure precipitates resulting in brittle behavior in 850 °C annealing treatment. Simulation result show that squeeze load of ECAP is larger than 100 ton but it can be reduced when exit angle of channel is larger than entrance. Outer corner of ECAP with 90 ̊ generate lower squeeze pressure than that of 40 ̊.

Deformation Stability of a Low-Cost Titanium Alloy Used for Petroleum Drilling Pipe

2019 ◽  
Vol 944 ◽  
pp. 887-891
Author(s):  
Long Jiang ◽  
Chun Feng ◽  
Hui Qun Liu ◽  
Le Wang ◽  
Li Hong Han ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Strain Rate ◽  
Flow Instability ◽  
Low Cost ◽  
True Strain ◽  
Strain Rate Range ◽  
Strain Rates ◽  
Arc Melting ◽  
Deformation Stability ◽  
Petroleum Drilling

A new modified low-cost titanium alloy, Ti-Al-X, was designed for petroleum drilling applications. The alloy ingots were prepared by combination of vacuum consumable electrode arc melting, forging/hot rolling, homogenization, and solid-solution/aging treatments. The hot deformation behavior of Ti-Al-X alloy was investigated by a thermal simulation machine Gleeble 1500 at temperature range of 850~1000°C with the strain rate range of 0.001 s-1~1s-1. The deformation resistance significantly decreases with the increase of deformation temperature and the strain rate. The alloy exhibits flow instability under the deformation conditions of strain rates about 0.001 s-1 and temperature above 1000°C, which should be avoided during hot working. In addition, the instability area enlarged in processing map with the increasing of true strain.

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