Microstructure Control and Mechanical Property Correlation in Titanium Alloy Ti-6Al-4V Fasteners for Space Applications

2015 ◽  
Vol 830-831 ◽  
pp. 354-357
Author(s):  
S.V.S. Narayana Murty ◽  
Sushant Manwatkar ◽  
P. Ramesh Narayanan
Keyword(s):  
Mechanical Property ◽  
Titanium Alloy ◽  
High Strength ◽  
Beta Phase ◽  
Strength Properties ◽  
Head Region ◽  
Two Phase ◽  
Space Applications ◽  
Β Phase ◽  
Torque Values

High strength fasteners of Titanium alloy Ti-6Al-4V are widely used in both launch vehicle and satellite structures. Ti-6Al-4V fasteners having three different types of microstructures were analysed for mechanical properties to understand the role of two phase α+β or transformed β phase in the head region. Based on the microstructure-mechanical property correlations, it was concluded that the presence of transformed beta phase will not affect the strength properties, but will produce scatter in percentage elongation, percentage reduction in area and failure torque values. Therefore, it is recommended that the microstructure of aerospace titanium alloy Ti-6Al-4V fasteners should contain homogeneous two phase α+β throughout.

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.

scholarly journals Effect of thermal cycling on mechanical and microstructural properties of heat-treated Ti-6Al-4V alloy

2022 ◽  
Author(s):  
Venkata Siva Teja Putti ◽  
S Manikandan ◽  
Kiran Kumar Ayyagari
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Weight Ratio ◽  
High Strength ◽  
Stress Relief ◽  
Strength Properties ◽  
Thermal Cycles ◽  
Β Phase ◽  
Solution Treated ◽  
Heat Treated

Abstract Titanium (Ti-6Al-4V) is an α+β phase-field alloy utilized in many industries due to its high strength-to-weight ratio and near-net shaping capability. Solution treated & aging, and stress relief annealing processes were performed on the samples to increase the strength and % of elongation. The heat-treated samples then thermally cycled for 500 cycles, 1000 cycles, and 1500 cycles to evaluate the microhardness and tensile properties. The presence of martensite and α2 precipitates in the thermally cycled samples was confirmed by scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). In this investigation, at 1000 thermal cycles, all specimens show improvement in both hardness and strength when compared within the cycles. Solution-treated and aging (STA), stress relief annealing (SRA), and without any heat-treatment (WHT) processes have their highest hardness values recorded for 1000 thermal cycles, and the values are 471 HV0.5, 381 HV0.5, and 374.6HV0.5, respectively. For the SRA process, ultimate tensile strength (UTS) of 925 MPa and yield strength (YS) of 896 MPa have resulted in 1000 cycles. Similarly, at 1000 thermal cycle WHT processed samples yielded UTS of 920 MPa and YS of 885 MPa. STA process samples that are heat-treated for 1000 thermal cycles have better strength properties than SRA and WHT and had a UTS of 1530MPa and YS of 1420MPa. From a ductility point of view, a maximum elongation of 29% for the STA process has resulted. Compared to forged titanium alloy (base metal), an increase of 31% elongation and 41% ultimate tensile strength for solution treated and aging process at 1000 cycles has resulted in this investigation.

Effect of Annealing Process on Microstructure and Tensile Properties of TC16 Titanium Alloy after Rapid Heat Treatment

2021 ◽  
Vol 1032 ◽  
pp. 152-156
Author(s):  
Peng Lei ◽  
Shu Cheng Dong ◽  
Guang Yu Ma ◽  
Tuo Cheng ◽  
O.M. Ivasishin
Keyword(s):  
Heat Treatment ◽  
Titanium Alloy ◽  
Tensile Properties ◽  
High Strength ◽  
Optical Microscope ◽  
Annealing Process ◽  
Test Machine ◽  
Two Phase ◽  
Reduction Of Area ◽  
Rapid Heat Treatment

TC16 titanium alloy is a martensite α+β two-phase high strength titanium alloy, which can improve its structure and enhance properties through heat treatment. Effect of annealing process on microstructure and tensile properties of TC16 titanium alloy was investigated using optical microscope, scanning electron microscope and universe tensile test machine. The results show that when annealed at 720°C for 4h then furnace cooling to ambient temperature, the tensile strength of the TC16 alloy reaches nearly 900MPa,the elongation reaches 19.6% and the reduction of area reaches 65%, which present a good comprehensive performance.

Phase Stability of Sigma + Beta Microstructures in the Ternary Nb-Ti-Al System

1990 ◽  
Vol 194 ◽  
Author(s):  
D. T. Hoelzer ◽  
F. Ebrahimi
Keyword(s):  
Phase Stability ◽  
Orthorhombic Phase ◽  
Beta Phase ◽  
Phase Region ◽  
Nominal Composition ◽  
Two Phase ◽  
Σ Phase ◽  
Β Phase ◽  
Heat Treated ◽  
The Stability

AbstractAn alloy with the nominal composition 42Nb-28Ti-30Al (at.%) was heat treated in the sigma + beta phase region. The evolution of σ phase from the metastable β phase and the stability of the two-phase microstructure at various aging temperatures were evaluated using TEM techniques. The results indicate that the β phase in equilibrium with the σ phase at high temperatures decomposes to the orthorhombic phase at temperatures below 1200°C.

scholarly journals Effects of Trace Erbium Addition on Microstructure and Mechanical Properties of Ti6Al4V-xEr Alloys

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 628 ◽  
Author(s):  
Yakun Wu ◽  
Yanhua Guo ◽  
Guanglong Xu ◽  
Hui Chang ◽  
Yuwen Cui
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Earth Element ◽  
Grain Refining ◽  
Microstructural Characteristics ◽  
Two Phase ◽  
Β Phase ◽  
Hardness Tests ◽  
Strength And Plasticity ◽  
Titanium Alloy Ti6al4v

In order to discern the effect of rare earth element Er addition on grain refinement of the most widely used titanium alloy Ti6Al4V, new erbium modified Ti6Al4V alloys with compositions of Ti6Al4V-xEr (x = 0, 0.2, 0.4, 0.6 wt %) were developed and investigated for their microstructural characteristics and mechanical properties in comparison with their unmodified baseline alloy. Microstructural examinations revealed that, by adding Er, (1) the microstructure primarily retained a two-phase structure consisting of α and β, (2) remarkable grain refining occurred, and (3) some Er2O3 and Al2Er disperses were formed largely around the β phase and near the grain boundaries. Mechanical property measurements evidenced an overall enhancement under tension and hardness tests. An increase in both strength and plasticity with increasing Er content was obtained but followed by a drop, while a gradual monotonous improvement in hardness was achieved. The Ti6Al4V-0.2Er alloy exhibits optimal mechanical properties.

scholarly journals Improving of Mechanical Properties of Titanium Alloy VT23 due to Impact-Oscillatory Loading and the Use of Carbon Nano-Solution

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 652
Author(s):  
Mykola Chausov ◽  
Oleg Khyzhun ◽  
Janette Brezinová ◽  
Pavlo Maruschak ◽  
Andrii Pylypenko ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Titanium Alloy ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
High Strength ◽  
Surface Layers ◽  
Two Phase ◽  
X Ray ◽  
Alloy Vt23

Improvement in the mechanical properties of sheet two-phase high-strength titanium alloy VT23 due to impact-oscillatory loading and the use of carbon nanosolutions at room temperature was tested experimentally. It was shown that in addition to obtaining a significant increase in the initial plastic deformation of the alloy, it is possible to strengthen the surface layers of the alloy by a factor of 8.4% at a time via the impulse introduction of energy into the alloy and the use of carbon nanosolutions. Using X-ray photoelectron spectroscopy (XPS), it was first found that strengthening of the surface layers of the titanium alloy at a given load, in line with using a carbon nanosolution, leads to the formation of a mixture of titanium oxide and titanium carbide or oxycarbide of type TiO2−xCx on the surface.

scholarly journals Effect of Heat Treatment on the Mechanical Properties of Two-Phase Titanium Alloy Ti6al7nb/ Wpływ Obróbki Cieplnej Na Własności Mechaniczne Dwufazowego Stopu Tytanu Ti6al7nb

2014 ◽  
Vol 59 (4) ◽  
pp. 1713-1716 ◽  
Author(s):  
R. Dąbrowski
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Titanium Alloy ◽  
Yield Strength ◽  
Cooling Rate ◽  
Strength Properties ◽  
Two Phase ◽  
Impact Tests ◽  
Alloy Heat

Abstract Mechanical properties of the two-phase titanium alloy Ti6Al7Nb, after the heat treatment based on soaking this alloy in the α + β range, cooling in water or oil and ageing at two selected temperatures, were determined in the hereby paper. The alloy mechanical properties were determined in tensile and impact tests, supported by the fractographic analysis of fractures. In addition, its hardness was measured and the analysis of changes occurring in the microstructure was performed for all variants of the alloy heat treatment. Regardless of the applied cooling rate of the alloy, from a temperature of 970°C followed by ageing at 450 and 650°C, none essential changes were noticed in its microstructure. It was shown that applying less intensive cooling medium (oil) instead of water (before tempering) decreases strength properties indicators, i.e. tensile strength and yield strength as well as hardness (only slightly). The decrease of the above mentioned indicators is accompanied by an increase of an elongation and impacts strength. Fractures of tensile and impact tests are of a ductile character regardless of the applied heat treatment.

scholarly journals Effect of Third-Stage Heat Treatments on Microstructure and Properties of Dual-Phase Titanium Alloy

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2776
Author(s):  
Xiqin Mao ◽  
Meigui Ou ◽  
Desong Chen ◽  
Ming Yang ◽  
Wei Long
Keyword(s):  
Tensile Strength ◽  
Titanium Alloy ◽  
Aging Treatment ◽  
Air Cooling ◽  
Phase Zone ◽  
Two Phase ◽  
Β Phase ◽  
Solution Treated ◽  
Α Phase ◽  
Third Stage

Two-phase TC21 titanium alloy samples were solution-treated at 990 °C (β phase zone) and cooled by furnace cooling (FC), air cooling (AC), and water quenching (WQ), respectively. The second solution stage treatment was carried out at 900 °C (α + β phase zone), then aging treatment was performed at 590 °C. The influence of the size and quantity of the α phase on the properties of the sample were studied. The experimental results showed as the cooling rate increased after the first solution stage treatment, wherein the thickness of primary layer α gradually decreased, and the tensile strength and yield strength gradually increased. After the second solution stage treatment, the tensile properties of samples increased due to the quantity of layers α increased. The aging treatment promoted the precipitation of the dispersed α phase and further improved the tensile strength. After the third solution stage treatments, the FC samples with more β-phase had the best comprehensive mechanical properties.

The influence of heat treatment on the formation of the structure and the level of mechanical properties of high-alloyed titanium alloy

2020 ◽  
pp. 28-41
Author(s):  
I. R. Kozlova ◽  
E. V. Chudakov ◽  
N. V. Tretyakova ◽  
Yu. M. Markova ◽  
E. A. Vasilieva
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Titanium Alloy ◽  
Thermal Action ◽  
High Strength ◽  
Heterogeneous Structure ◽  
Two Phase ◽  
Structure Changes ◽  
Hardened State ◽  
Alloyed Titanium

The paper investigates the possibility of increasing the strength of the experimental high-alloyed titanium alloy due to various methods of thermal action, leading to a change in its phase composition and intragrain structure. Changes in mechanical properties in correlation with the change in structure in the annealed, tempered and heat-hardened state are reviewed. It is shown that by controlling phase transformations in highalloyed two-phase titanium alloys, it is possible to realize high-strength state with satisfactory plastic characteristics. The optimal complex of mechanical properties is provided by heat treatment, which leads to the creation of a two-phase heterogeneous structure with a developed bimodal intragrain structure.

scholarly journals The Influences of Process Annealing Temperature on Microstructure and Mechanical Properties of near β High Strength Titanium Alloy Sheet

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1478 ◽  
Author(s):  
Zhaoxin Du ◽  
Yan Ma ◽  
Fei Liu ◽  
Ning Xu ◽  
Yanfei Chen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Titanium Alloy ◽  
Cold Rolling ◽  
Phase Field ◽  
Annealing Temperature ◽  
High Strength ◽  
Goss Texture ◽  
Β Phase ◽  
Cold Rolled ◽  
Process Annealing

The influences of process annealing temperature during cold rolling on microstructure and mechanical properties of Ti-3.5Al-5Mo-6V-3Cr-2Sn-0.5Fe near β high strength titanium alloy sheets have been investigated. Results showed that the alloy mainly included the deformation induced dislocation structures after cold rolling but no obvious band structure, twin crystal or martensite were observed in this work. The texture components, which were affected by process annealing, are mainly γ-fiber, α-fiber and weak Goss texture. The γ-fiber of alloy when process annealed at 780 °C (α/β phase field) is stronger than at 830 °C (β phase field), where the Goss texture of alloy with process annealing temperature of 830 °C is more obvious. Results of annealing heat treatments showed that the recrystallization of the cold rolled was basically completed in a relatively short time of 2 min at 750 °C for 2 min. The refinement of grain size led to a significant increase of plasticity compared to rolled alloy. Results of tensile testing of aged alloy display the excellent combination of strength and plasticity, and the cold rolled alloy with process annealed at α/β phase field exhibits the better mechanical properties than at β phase field.

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