Influence of Aging Temperature on Microstructure and Creep Properties of Hot Continuous Rolled Ti-6Al-4V Alloy

2012 ◽  
Vol 560-561 ◽  
pp. 943-946
Author(s):  
Li Xiao ◽  
Su Gui Tian ◽  
Xian Yu Bao
Keyword(s):  
Strain Rate ◽  
Aging Temperature ◽  
Creep Property ◽  
Solution Treatment ◽  
Continuous Rolling ◽  
Β Phase ◽  
Industrial Manufacture ◽  
Hot Continuous Rolling ◽  
New Processing ◽  
Lower Temperature

Hot continuous rolling technique is a new processing method for preparing Titanium alloy, which may decrease the production cost and realize continuous industrial manufacture. Ti-6Al-4V alloy was prepared by hot continuous rolling (HCR) and solution and aging treated at different temperature. Creep curves of the alloys were measured, microstructure evolution feature of the alloys during creep was observed by SEM and TEM. The influence of aging temperature on the microstructure and creep property of the alloy is briefly discussed. Results show that, the microstructure of HCR alloy after solution treatment at temperature higher than β phase transus point consists of the fully "basket weave" structure. The alloy aged at 750 °C has higher strain rate and shorter creep lifetime, strain rate of the alloy during steady-state creep is measured to be 0.69 × 10-7/s, creep lifetime is measured to be 180h, and strain rate of the alloy aged at 480 °C is measured to be 0.33 × 10-7/s. The alloy aged at lower temperature has longer creep lifetime than the alloy aged at high temperature.

Enhancement of Mechanical Properties of Cast Beta-Type Titanium Alloy by Aging Treatment

2018 ◽  
Vol 929 ◽  
pp. 42-49
Author(s):  
Zuldesmi Mansjur ◽  
Hendro Maxwel Sumual
Keyword(s):  
Mechanical Properties ◽  
Aging Time ◽  
Vickers Hardness ◽  
Aging Temperature ◽  
Dendritic Structure ◽  
Solution Treatment ◽  
Aging Treatment ◽  
High Oxygen Content ◽  
Precision Casting ◽  
Β Phase

Beta type Ti-29Nb-13Ta-4.6Zr alloy (TNTZ) is one of the titanium alloys which have gained much attention in dental applications. Dental precision casting is predominant for fabricating dental prostheses. However, there is a possibility for the mechanical properties of its casting to be degraded because of a α case, shrinkages and pores and a dendrite structure. One of the ways to enhance their mechanical properties is heat treatment process. Therefore, the aim of this study is to investigate the effect of aging treatment on mechanical properties and microstructure of TNTZ cast into magnesia based mold in order to improve its mechanical properties. As results, the Vickers hardness of the cast TNTZ after solution treatment is larger than that of the wrought TNTZ. The aging curve of the cast and the wrought TNTZ at an aging temperature of 673 K and 723 K exhibit almost similar pattern. For each aging time, the higher the aging temperature, the smaller the Vickers hardness for both alloys. Microstructures of cast TNTZ at various aging conditions consist of a dendritic structure and the average diameters of their grain size are around 40 μm. The diffraction peaks of precipitation of α and β phase s are detected in under aging (UA), peak aging (PA) and over aging (OA) conditions for both aging temperatures. However, the diffraction peak of ω phase is observed only in OA condition for cast TNTZ at aging temperature of 673 K. The highest tensile strength of the cast TNTZ and the wrought TNTZ at both aging temperatures are in PA condition and the elongation decrease continuously by increasing aging time. The tensile strengths of cast TNTZ in UA, PA and OA conditions at an aging temperature of 723 K are lower and their elongations are higher in comparison with those of 673 K. The high oxygen content seems to contribute to the poor elongation. SEM fractographs of the cast TNTZ at aging temperatures of 673 and 723 K in UA, PA and OA conditions show the brittle morphology with intergranular fracture that increases with increasing of aging time.

scholarly journals Effects of solution and aging treatment parameters on the microstructure evolution of Ti–10V–2Fe–3Al alloy

2020 ◽  
Vol 39 (1) ◽  
pp. 501-509
Author(s):  
Wan-Liang Zhang ◽  
Wen-Tao Hao ◽  
Wei Xiong ◽  
Guo-Zheng Quan ◽  
Jiang Zhao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aging Temperature ◽  
Treatment Process ◽  
Solution Treatment ◽  
Aging Treatment ◽  
Solution Temperature ◽  
Air Cooling ◽  
Water Cooling ◽  
Β Phase ◽  
Aging Conditions

AbstractThe solution-aging treatment parameters, including solution temperature, cooling rate and aging temperature, have significant influences on the microstructures and comprehensive mechanical properties of titanium alloy. In this work, the detailed microevolution behaviors of Ti–10V–2Fe–3Al alloy under different solution and aging conditions have been investigated through a series of heat-treatment experiments. The results of solution-treatment experiments reveal that the content of αp-phase is reduced to zero as the solution temperature is raised to a certain α → β critical transformation point. Recrystallized β-grains can be observed at the solution temperature of 820°C. In addition, the cooling way (air cooling or water cooling) has little influence on the microevolution behaviors for this alloy during the solution-treatment process. As for the solution-aging-treatment experiments, the results reveal that αs-phases are precipitated from the supersaturated β-phase, and the fraction of αs-phase increases with increasing aging temperature. However, the precipitated α-grains intend to coalesce and coarsen as the aging temperature raises above 510°C. Therefore, the advocated solution-aging-treatment program is solution treatment at 820°C with air cooling followed by aging treatment at 510°C with air cooling.

Effect of high strain rate beta processing on microstructure and mechanical properties of near-β titanium alloy Ti-10V-2Fe-3Al

2015 ◽  
Vol 232 (3) ◽  
pp. 181-190 ◽  
Author(s):  
P Skubisz ◽  
Ł Lisiecki ◽  
M Paćko ◽  
T Skowronek ◽  
P Micek ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Titanium Alloy ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Thermomechanical Processing ◽  
Solution Treatment ◽  
Β Phase ◽  
Phase Range ◽  
Size And Morphology

The article presents microstructures and mechanical properties of near-β Ti-10V-2Fe-3Al titanium wrought alloy after two differentiated processing cycles. The assumed processing paths involved high strain rate hot deformation in β-phase range, followed by solution treatment with variation of cooling rate and subsequent single or double aging. To estimate the effects of the assumed treatment cycles, optical microscopy and scanning electron microscopy microstructure analysis was conducted, with special attention paid to evolution of alpha precipitates in consecutive stages of processing and their role in grain refinement. The correlation between tensile properties and grain size, as well as the amount of precipitates amount was found to be connected with alpha-plates’ size and morphology. It was concluded that in case of Ti-10V-2Fe-3Al titanium alloy, proposed cycles of thermomechanical processing allow reduction of inhomogeneous recrystallization resulting in necklace substructure. On the other hand, high strain rate promotes mechanical properties improvement, as it favors fragmentation of continuous grain-boundary α precipitates.

scholarly journals Effect of High Strain Rate on Adiabatic Shearing of α+β Dual-Phase Ti Alloy

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2044
Author(s):  
Fang Hao ◽  
Yuxuan Du ◽  
Peixuan Li ◽  
Youchuan Mao ◽  
Deye Lin ◽  
...  
Keyword(s):  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Damage Tolerance ◽  
Shear Bands ◽  
Dual Phase ◽  
Ti Alloy ◽  
Hopkinson Pressure Bar ◽  
Β Phase ◽  
Schmid Factor ◽  
Pressure Bar

In the present work, the localized features of adiabatic shear bands (ASBs) of our recently designed damage tolerance α+β dual-phase Ti alloy are investigated by the integration of electron backscattering diffraction and experimental and theoretical Schmid factor analysis. At the strain rate of 1.8 × 104 s−1 induced by a split Hopkinson pressure bar, the shear stress reaches a maximum of 1951 MPa with the shear strain of 1.27. It is found that the α+β dual-phase colony structures mediate the extensive plastic deformations along α/β phase boundaries, contributing to the formations of ASBs, microvoids, and cracks, and resulting in stable and unstable softening behaviors. Moreover, the dynamic recrystallization yields the dispersion of a great amount of fine α grains along the shearing paths and in the ASBs, promoting the softening and shear localization. On the contrary, low-angle grain boundaries present good resistance to the formation of cracks and the thermal softening, while the non-basal slipping dramatically contributes to the strain hardening, supporting the promising approaches to fabricate the advanced damage tolerance dual-phase Ti alloy.

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.

The Superplastic Properties and Microstructures Evolution of High Nb Ti3Al Based Alloy

2016 ◽  
Vol 838-839 ◽  
pp. 568-573 ◽  
Author(s):  
Xiu Quan Han ◽  
Ming Jie Fu
Keyword(s):  
Strain Rate ◽  
Work Hardening ◽  
Deformation Temperature ◽  
Volume Fraction ◽  
Alloy Sheet ◽  
Deformation Condition ◽  
Maximum Elongation ◽  
Β Phase ◽  
Superplastic Properties ◽  
Softening Stage

The superplasticity of high Nb Ti3Al based alloy - Ti-23Al-17Nb (at.%) alloy sheet under the conditions of 940~1000°C and 5.5×10-5s-1~1.7×10-3s-1are studied. The results show the elongation changes as a parabola with the deformation temperature increasing, and the maximum elongation obtained at 960°C and 5.5x10-5s-1 is 1447.5%. Work hardening stage increases much more than softening stage when strain rate is decreased due to the increasing of element Nb. Compared with primary microstructure, the lath-like α2 grains gradually disappeared, the α2 grains became more equiaxed, and the content and size of α2 grains are decreasing with increasing of deformation temperature. The volume fraction ratio of α2 and β phase at the optimum deformation condition is 50:50%. The cavities mechanism at the fracture tip was discussed; it can be defined that the cavities could be avoided when deformation temperature is higher than 940°C.

scholarly journals Effect of strain rate on α-lath thickness of TC17 alloy after deformation and subsequent heat treatment

2020 ◽  
Vol 321 ◽  
pp. 13003
Author(s):  
Zimin Lu ◽  
Jiao Luo ◽  
Miaoquan Li
Keyword(s):  
Heat Treatment ◽  
Strain Rate ◽  
Electron Backscatter Diffraction ◽  
Phase Region ◽  
Subsequent Heat Treatment ◽  
Strain Rates ◽  
Optical Micrograph ◽  
Β Phase ◽  
Electron Backscatter ◽  
Backscatter Diffraction

Effect of strain rate on α-lath thickness of TC17 alloy with a basketweave microstructure was studied in the present work. For this purpose, this alloy was deformed in the β phase region and subsequently soluted and aged in α+β phase region. Moreover, optical micrograph (OM) and electron backscatter diffraction (EBSD) were applied to analyze the change of lath thickness at different strain rates. The result showed that α-lath thickness increased with increasing strain rate. This phenomenon was possibly attributed to the higher degree of variant selection (DVS) at higher strain rate (0.1 s-1). The higher DVS was beneficial for the formation of parallel α-lath colonies during cooling after deformation. And, these parallel α-lath colonies would more easily grow up and coarsen during subsequent heat treatment. Therefore, α-lath at higher strain rate is more thick.

Effect of Solution Treatment on Microstructure and Mechanical Hardness of Ti-6Al-7Nb

2020 ◽  
Vol 860 ◽  
pp. 218-222
Author(s):  
Della Maharani ◽  
Anawati Anawati ◽  
I. Nyoman Jujur ◽  
Damisih
Keyword(s):  
Centrifugal Casting ◽  
Solution Treatment ◽  
Aging Treatment ◽  
Xrd Analysis ◽  
Optical Microscope ◽  
Alloying Element ◽  
Mechanical Hardness ◽  
Β Phase ◽  
Permanent Implant

The metastable β Ti-6Al-4V alloy has been used clinically as a permanent implant material owing to its suitable mechanical properties and biocompatibility. However, the alloying element V was accused of causing toxicity when released to human body fluid. In this work, Nb was used in the alloy to replace V. This study presents the characterization of microstructure and mechanical hardness of as-cast Ti-6Al-7Nb and after solution treatment. The Ti-6Al-7Nb alloy was fabricated by the centrifugal casting method. Solution treatment was carried out at 970°C for 1 hour, followed by oil quenching, and consecutively an aging treatment was applied at 500°C for 8 hours. The microstructure was studied by an optical microscope. The mechanical hardness was measured by microhardness Vickers. The results show that the mechanical hardness of the Ti-6Al-7Nb decreased from 396.2 to 377.2 HV as a result of the solution treatment. Reduction in the hardness was attributed to the phase transformation of α to the β phase during the solution treatment. The XRD analysis showed a reduction in the intensity of α phases at the (011), (012), and (020) planes in the alloy after the solution treatment. The results indicated that the microstructure and mechanical hardness of Ti-6Al7-Nb alloy were affected by the solution treatment.

scholarly journals Microstructure Evolution and Mechanical Properties of AZ80 Mg Alloy during Annular Channel Angular Extrusion Process and Heat Treatment

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4223 ◽  
Author(s):  
Xi Zhao ◽  
Shuchang Li ◽  
Fafa Yan ◽  
Zhimin Zhang ◽  
Yaojin Wu
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Microstructure Evolution ◽  
Solution Treatment ◽  
Aging Treatment ◽  
Annular Channel ◽  
Mg Alloy ◽  
Strengthening Effect ◽  
Β Phase ◽  
Angular Extrusion

Microstructure evolution and mechanical properties of AZ80 Mg alloy during annular channel angular extrusion (350 °C) and heat treatment with varying parameters were investigated, respectively. The results showed that dynamic recrystallization of Mg grains was developed and the dendritic eutectic β-Mg17Al12 phases formed during the solidification were broken into small β-phase particles after hot extrusion. Moreover, a weak texture with two dominant peaks formed owing to the significant grain refinement and the enhanced activation of pyramidal <c + a> slip at relative high temperature. The tension tests showed that both the yield strength and ultimate tensile strength of the extruded alloy were dramatically improved owing to the joint strengthening effect of fine grain and β-phase particles as compared with the homogenized sample. The solution treatment achieved the good plasticity of the alloy resulting from the dissolution of β-phases and the development of more equiaxed grains, while the direct-aging process led to poor alloy elongation as a result of residual eutectic β-phases. After solution and aging treatment, simultaneous bonding strength and plasticity of the alloy were achieved, as a consequence of dissolution of coarse eutectic β-phases and heterogeneous precipitation of a large quantity of newly formed β-phases with both the morphologies of continuous and discontinuous precipitates.

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).

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