Study of changes in the properties of titanium alloys subjected to neutron irradiation

2020 ◽  
pp. 181-187
Author(s):  
V. V. Larionov ◽  
V. A. Varlachev
Keyword(s):  
Titanium Alloy ◽  
Titanium Alloys ◽  
Neutron Irradiation ◽  
Gamma Rays ◽  
Neutron Shield

A change in the natural composition of titanium subjected to neutron irradiation with energies up to 0.1 MeV is shown. The process is accompanied by the formation of hydrogen and radioactive scandium. Gamma rays with energies of 889 and 1120 keV are observed. The effect of changing the natural composition of the titanium alloy and the presence of gamma studies should be taken into account when creating structural products and when creating a neutron shield based on titanium.

Study of the Key Issues of Friction Stir Welding of Titanium Alloy

2010 ◽  
Vol 638-642 ◽  
pp. 1185-1190 ◽  
Author(s):  
Hui Jie Liu ◽  
Li Zhou ◽  
Yong Xian Huang ◽  
Qi Wei Liu
Keyword(s):  
Titanium Alloy ◽  
Friction Stir Welding ◽  
Melting Point ◽  
Titanium Alloys ◽  
Welding Process ◽  
High Strength ◽  
Liquid Cooling ◽  
Friction Stir ◽  
Key Issues ◽  
Aluminum And Magnesium Alloys

As a new solid-state welding process, friction stir welding (FSW) has been successfully used for joining low melting point materials such as aluminum and magnesium alloys, but the FSW of high melting point materials such as steels and titanium alloys is still difficult to carry out because of their strict requirements for the FSW tool. Especially for the FSW of titanium alloys, some key technological issues need to solve further. In order to accomplish the FSW of titanium alloys, a specially designed tool system was made. The system was composed of W-Re pin tool, liquid cooling holder and shielding gas shroud. Prior to FSW, the Ti-6Al-4V alloy plates were thermo-hydrogen processed to reduce the deformation resistance and tool wear during the FSW. Based on this, the thermo-hydrogen processed Ti-6Al-4V alloy with different hydrogen content was friction stir welded, and the microstructural characterizations and mechanical properties of the joints were studied. Experimental results showed that the designed tool system can fulfill the requirements of the FSW of titanium alloys, and excellent weld formation and high-strength joint have been obtained from the titanium alloy plates.

scholarly journals Experimental Study of tool Wear Mechanisms in Conventional and High Pressure Coolant Assisted Machining of Titanium Alloy Ti17

2013 ◽  
Vol 554-557 ◽  
pp. 1961-1966 ◽  
Author(s):  
Yessine Ayed ◽  
Guenael Germain ◽  
Amine Ammar ◽  
Benoit Furet
Keyword(s):  
High Pressure ◽  
Titanium Alloy ◽  
Tool Wear ◽  
Titanium Alloys ◽  
Tool Life ◽  
Wear Mechanisms ◽  
Cutting Forces ◽  
Cutting Edge ◽  
Rake Face ◽  
High Pressure Coolant

Titanium alloys are known for their excellent mechanical properties, especially at high temperature. But this specificity of titanium alloys can cause high cutting forces as well as a significant release of heat that may entail a rapid wear of the cutting tool. To cope with these problems, research has been taken in several directions. One of these is the development of assistances for machining. In this study, we investigate the high pressure coolant assisted machining of titanium alloy Ti17. High pressure coolant consists of projecting a jet of water between the rake face of the tool and the chip. The efficiency of the process depends on the choice of the operating parameters of machining and the parameters of the water jet such as its pressure and its diameter. The use of this type of assistance improves chip breaking and increases tool life. Indeed, the machining of titanium alloys is generally accompanied by rapid wear of cutting tools, especially in rough machining. The work done focuses on the wear of uncoated tungsten carbide tools during machining of Ti17. Rough and finish machining in conventional and in high pressure coolant assistance conditions were tested. Different techniques were used in order to explain the mechanisms of wear. These tests are accompanied by measurement of cutting forces, surface roughness and tool wear. The Energy-dispersive X-ray spectroscopy (EDS) analysis technique made it possible to draw the distribution maps of alloying elements on the tool rake face. An area of material deposition on the rake face, characterized by a high concentration of titanium, was noticed. The width of this area and the concentration of titanium decreases in proportion with the increasing pressure of the coolant. The study showed that the wear mechanisms with and without high pressure coolant assistance are different. In fact, in the condition of conventional machining, temperature in the cutting zone becomes very high and, with lack of lubrication, the cutting edge deforms plastically and eventually collapses quickly. By contrast, in high pressure coolant assisted machining, this problem disappears and flank wear (VB) is stabilized at high pressure. The sudden rupture of the cutting edge observed under these conditions is due to the propagation of a notch and to the crater wear that appears at high pressure. Moreover, in rough condition, high pressure assistance made it possible to increase tool life by up to 400%.

Preparation of Titanium Alloy Parts by Powder Compact Extrusion of a Powder Mixture and Scaled up Manufacture

2016 ◽  
Vol 704 ◽  
pp. 75-84 ◽  
Author(s):  
Fei Yang ◽  
Brian Gabbitas ◽  
Ajit Pal Singh ◽  
Stella Raynova ◽  
Hui Yang Lu ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Powder Metallurgy ◽  
Titanium Alloys ◽  
Powder Mixture ◽  
Powder Compact ◽  
Blended Elemental ◽  
Pilot Plant Scale ◽  
Near Net Shape ◽  
Titanium Processing ◽  
The University

Blended Elemental Powder Metallurgy (BE-PM) is a very attractive method for producing titanium alloys, which can be near-net shape formed with compositional freedom. However, a minimization of oxygen pick-up during processing into manufactured parts is a big challenge for powder metallurgy of titanium alloys. In this paper, different approaches for preparing titanium alloy parts by powder compact extrusion with 0.05-0.1wt.% of oxygen pick-up during manufacturing are discussed. The starting materials were a powder mixture of HDH titanium powder, other elemental powders and a master alloy powder. Different titanium alloys and composites, such as Ti-6Al-4V, Ti-4Al-4Sn-4Mo-0.5Si, Ti-5Al-5V-5Mo-3Cr, and Ti-5Al-5V-5Mo-3Cr-5vol%TiB, with different profiles such as round and rectangular bars, a wedge profile, wire and tubes have been successfully manufactured on a laboratory and pilot-plant scale. Furthermore, a possible route for scaling up the titanium processing capabilities in the University of Waikato has also been discussed.

Increasing the titanium alloys durability due to modifications by vibro-abrasive processing of the strengthened surface layer

2021 ◽  
pp. 301-308
Author(s):  
V.V. Altukhova ◽  
R.F. Krupsky ◽  
A.A. Krivenok ◽  
O.G. Shakirova
Keyword(s):  
Titanium Alloy ◽  
Surface Layer ◽  
Nitric Acid ◽  
Titanium Alloys ◽  
Surface Hardening ◽  
World Science ◽  
Impact Surface ◽  
Current State ◽  
State Of Research ◽  
Defective Surface

It is shown that vibroabrasive treatment of hardened titanium alloy specimens contributes to an increase in their durability. This effect is explained by the removal of a defective surface layer containing microcracks and subject to the influence of residual tensile stresses. It is shown that the proposed stage of vibro-abrasive processing with ceramic granules makes it possible to almost completely remove iron introduced after vibro-impact surface hardening, which makes it possible to exclude the operation of etching in nitric acid from the technological process. The current state of research on durability in world science is briefly presented.

Study of Metal, Silicon Carbide Crystals and Ceramic Bond Transfer to the Surface of Titanium Alloy during Grinding

2021 ◽  
Vol 316 ◽  
pp. 515-520
Author(s):  
Vladimir A. Nosenko ◽  
Alexander V. Fetisov ◽  
Nikita D. Serdyukov
Keyword(s):  
Silicon Carbide ◽  
Titanium Alloy ◽  
Titanium Alloys ◽  
Morphological Analysis ◽  
Abrasive Tool ◽  
Adhesive Interaction ◽  
Dual Beam ◽  
Ceramic Bond ◽  
Wear Products ◽  
Brittle Destruction

The high adhesive activity of titanium alloys in interaction with abrasive materials is the main cause of poor grinding treatment. The most common abrasive material for grinding titanium alloys is silicon carbide. Silicon carbide wheels operate primarily in self-sharpening mode. Wear of the abrasive tool in the self-sharpening mode occurs as a result of brittle destruction of the fret. The purpose of the study was to determine experimentally the crystalline wear products of an abrasive tool, made of silicon carbide, on the treated surface during grinding of a titanium alloy. Samples of VT9 titanium alloy were processed by flat mortise grinding by a wheel of silicon carbide with the use of VOLTES coolant and the characteristic of the abrasive tool - 64CF80L7V. The treated surface was examined on the electron microscope Versa 3D Dual Beam. The condition of the treated surface testifies to the intensive adhesive interaction of the titanium alloy with the abrasive tool. The thickness of the metal deposits reaches 3 microns. As a result of morphological analysis, objects are identified on the treated surface, the appearance of which allows us to attribute them to crystals. The chemical composition of the selected objects was determined by a microprobe analysis in a microscope camera. On the basis of the conducted researches, a presence on the grinded surface of silicon carbide crystals of various sizes and a ceramic ligament is established.

Martensite decomposition during post-heat treatments and the aging response of near-α Ti–6Al–2Sn–4Zr–2Mo (Ti-6242) titanium alloy processed by selective laser melting (SLM)

2021 ◽  
pp. 2050018
Author(s):  
Haiyang Fan ◽  
Yahui Liu ◽  
Shoufeng Yang
Keyword(s):  
Titanium Alloy ◽  
High Temperature ◽  
Titanium Alloys ◽  
Selective Laser Melting ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Aging Treatment ◽  
Water Quenching ◽  
Laser Melting ◽  
Aging Response

Ti–6Al–2Sn–4Zr–2Mo (Ti-6242), a near-[Formula: see text] titanium alloy explicitly designed for high-temperature applications, consists of a martensitic structure after selective laser melting (SLM). However, martensite is thermally unstable and thus adverse to the long-term service at high temperatures. Hence, understanding martensite decomposition is a high priority for seeking post-heat treatment for SLMed Ti-6242. Besides, compared to the room-temperature titanium alloys like Ti–6Al–4V, aging treatment is indispensable to high-temperature near-[Formula: see text] titanium alloys so that their microstructures and mechanical properties are pre-stabilized before working at elevated temperatures. Therefore, the aging response of the material is another concern of this study. To elaborate the two concerns, SLMed Ti-6242 was first isothermally annealed at 650[Formula: see text]C and then water-quenched to room temperature, followed by standard aging at 595[Formula: see text]C. The microstructure analysis revealed a temperature-dependent martensite decomposition, which proceeded sluggishly at [Formula: see text]C despite a long duration but rapidly transformed into lamellar [Formula: see text] above the martensite transition zone (770[Formula: see text]C). As heating to [Formula: see text]C), it produced a coarse microstructure containing new martensites formed in water quenching. The subsequent mechanical testing indicated that SLM-built Ti-6242 is excellent in terms of both room- and high-temperature tensile properties, with around 1400 MPa (UTS)[Formula: see text]5% elongation and 1150 MPa (UTS)[Formula: see text]10% elongation, respectively. However, the combination of water quenching and aging embrittled the as-built material severely.

Erosion-Resistant PVD ZrAlCuN Coating for Titanium Alloy

2010 ◽  
Vol 150-151 ◽  
pp. 51-55 ◽  
Author(s):  
Jun Du ◽  
Ping Zhang ◽  
Jun Jun Zhao ◽  
Zhi Hai Cai
Keyword(s):  
Mechanical Properties ◽  
Titanium Alloy ◽  
Titanium Alloys ◽  
Vapor Deposition ◽  
Physical Vapor Deposition ◽  
Erosion Resistance ◽  
Zirconium Nitride ◽  
Erosion Rates ◽  
Sand Erosion ◽  
Nitride Coatings

Titanium alloys are susceptible to sand erosion, hard zirconium nitride coatings have been deposited onto titanium alloys by Physical vapor deposition (PVD) in order to improve erosion resistance. Al and Cu were added into ZrN coatings to strength and toughing the coating. The microstructure and mechanical properties of ZrAlCuN coating were studied. Erosion tests were conducted to evaluate anti-erosion ability. Erosion rates were measured and characteristic damage features were identified on the surface of eroded specimens. The mechanisms of erosion are discussed in order to explain the promising performance of materials in erosive conditions. It was found that there is an significant increase of erosion resistance because of the increase of hardness and toughness.

scholarly journals Simulation and Experimental Study of Dynamical Recrystallization Kinetics of TB8 Titanium Alloys

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4429
Author(s):  
Wenwei Zhang ◽  
Qiuyue Yang ◽  
Yuanbiao Tan ◽  
Min Ma ◽  
Song Xiang ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Titanium Alloys ◽  
Volume Fraction ◽  
Effective Strain ◽  
Processing Parameters ◽  
Good Prediction ◽  
Fem Method ◽  
Central Regions ◽  
Dynamical Recrystallization ◽  
3D Software

The dynamic recrystallization (DRX) behavior in the hot working of TB8 titanium alloy was studied by using the experiment and finite element simulation (FEM) method. The results showed that the DRX behavior of TB8 titanium alloys was drastically affected by the hot processing parameters. The rising deformation temperature and reducing strain rate led to an augmentation in the grain size (dDRX) and volume fraction (XDRX) of DRX grains. In view of the true stress–strain curves gained from the experiment, the dDRX and XDRX models of DRX grains were constructed. Based on the developed models for DRX of TB8 titanium alloy, the isothermal forging process of the cylindrical samples was simulated by the DEFORM-3D software. The distributions of the effective strain and XDRX for DRX were analyzed. A comparison of the dDRX and XDRX of DRX grains in the central regions of the samples between the experimental and FEM results was performed. A good correlation between the experimental and simulation results was obtained, indicating that the established FEM model presented good prediction capabilities.

scholarly journals A Review on Diffusion Bonding between Titanium Alloys and Stainless Steels

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
De-feng Mo ◽  
Ting-feng Song ◽  
Yong-jian Fang ◽  
Xiao-song Jiang ◽  
Charles Q. Luo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Titanium Alloy ◽  
Titanium Alloys ◽  
Stainless Steels ◽  
Diffusion Bonding ◽  
Low Cost ◽  
Phase Interface ◽  
Intermetallic Phases ◽  
Voids Growth

High-quality joints between titanium alloys and stainless steels have found applications for nuclear, petrochemical, cryogenic, and aerospace industries due to their relatively low cost, lightweight, high corrosion resistance, and appreciable mechanical properties. This article reviews diffusion bonding between titanium alloys and stainless steels with or without interlayers. For diffusion bonding of a titanium alloy and a stainless steel without an interlayer, the optimized temperature is in the range of 800–950°C for a period of 60–120 min. Sound joint can be obtained, but brittle FeTi and Fe-Cr-Ti phases are formed at the interface. The development process of a joint mainly includes three steps: matching surface closure, growth of brittle intermetallic compounds, and formation of the Kirkendall voids. Growth kinetics of interfacial phases needs further clarification in terms of growth velocity of the reacting layer, moving speed of the phase interface, and the order for a new phase appears. The influence of Cu, Ni (or nickel alloy), and Ag interlayers on the microstructures and mechanical properties of the joints is systematically summarized. The content of FeTi and Fe-Cr-Ti phases at the interface can be declined significantly by the addition of an interlayer. Application of multi-interlayer well prevents the formation of intermetallic phases by forming solid solution at the interface, and parameters can be predicted by using a parabolic diffusion law. The selection of multi-interlayer was done based on two principles: no formation of brittle intermetallic phases and transitional physical properties between titanium alloy and stainless steel.

scholarly journals An experimental research on the machinability of a high temperature titanium alloy BTi-6431S in turning process

2018 ◽  
Vol 5 ◽  
pp. 12
Author(s):  
Yanfeng Gao ◽  
Yongbo Wu ◽  
Jianhua Xiao ◽  
Dong Lu
Keyword(s):  
Titanium Alloy ◽  
High Temperature ◽  
Tool Wear ◽  
Titanium Alloys ◽  
Cutting Forces ◽  
Shear Bands ◽  
Cutting Parameters ◽  
Aircraft Manufacturing ◽  
Mechanical And Physical Properties ◽  
Alpha Titanium

Titanium alloys are extensively applied in the aircraft manufacturing due to their excellent mechanical and physical properties. At present, the α + β alloy Ti6Al4V is the most commonly used titanium alloy in the industry. However, the highest temperature that it can be used only up to 300 °C. BTi-6431S is one of the latest developed high temperature titanium alloys, which belongs to the near-α alloy group and has considerably high tensile strength at 650 °C. This paper investigates the machinability of BTi-6431S in the terms of cutting forces, chip formation and tool wear. The experiments are carried out in a range of cutting parameters and the results had been investigated and analyzed. The investigation shows that: (1) the specific cutting forces in the machining of BTi-6431S alloy are higher than in the machining of Ti6Al4V alloy; (2) the regular saw-tooth chips more easily formed and the shear bands are narrower in the machining of BTi-6431S; (3) SEM and EDS observations of the worn tools indicate that more cobalt elements diffuse into the workpiece from tool inserts during machining of BTi-6431S alloy, which significantly aggravates tool wear rate. The experimental results indicate that the machinability of BTi-6431S near alpha titanium alloy is significantly lower than Ti-6Al-4V alloy.

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