An Experimental Investigation Into the High Speed Turning of Ti-6Al-4V Titanium Alloy

2010 ◽  
Author(s):  
Anil K. Srivastava ◽  
Jon Iverson
Keyword(s):  
Titanium Alloy ◽  
Titanium Alloys ◽  
High Speed ◽  
Elevated Temperatures ◽  
Chemical Reactivity ◽  
Specific Strength ◽  
Aerospace Applications ◽  
Layered Coatings ◽  
High Specific Strength ◽  
Cutting Speeds

Titanium and its alloys have seen increased utilization in military and aerospace applications due to combination of high specific strength, toughness, corrosion resistance, elevated-temperature performance and compatibility with polymer composite materials. Titanium alloys are difficult to machine due to their inherent low thermal conductivity and higher chemical reactivity with other materials at elevated temperatures. In general, temperature related machining difficulties are encountered at production speeds in the range of 60 m/min and high-speed machining of these alloys has created considerable interest to researchers, tool manufacturers and end users. This paper provides recent results obtained during turning operation with the aim of improving machinability of titanium alloys. Several tests have been conducted using (i) micro-edge prep geometry of the inserts, (ii) ultra-hard PVD coated, and (iii) nano-layered coated inserts and the effects of speeds and feeds during turning of Ti-6Al-4V titanium alloy are discussed. The initial tests have been conducted under orthogonal (2-D) cutting conditions with no coolant application. Based on these results, several oblique cutting (3-D) tests have been designed and conducted to study the effect of various types of ultra-hard and nano-layered coatings at higher cutting speeds under flooded coolant conditions. The effects of speed and feed on cutting force and tool wear are presented in this paper.

3D Numerical Investigation of Effect of Milling Process Parameters on High Speed Milling of Ti-Al6-V4

2012 ◽  
Author(s):  
J. Ma ◽  
Shuting Lei ◽  
Huaqi Lu
Keyword(s):  
Titanium Alloy ◽  
Titanium Alloys ◽  
Numerical Investigation ◽  
Process Parameters ◽  
High Speed ◽  
Chemical Reactivity ◽  
Milling Process ◽  
Depth Of Cut ◽  
High Speed Milling ◽  
Axial Depth

Titanium alloys are widely used in aerospace industry owing to excellent mechanical properties. While because of high chemical reactivity and low thermal conductivity, titanium alloys are classified as hard-to-cut materials. In this paper, Finite Element Method (FEM) is employed to conduct numerical investigation in the effects of milling process parameters (milling speeds, feed per tooth, and axial depth of cut) on three-dimensional (3D) high speed milling of Titanium alloy (Ti-6Al-4V). The tool material used is Carbide and Johnson-Cook plastic model is employed to model the workpiece due to its capability of modeling large strains, high strain rates, and temperature dependent visco-plasticity. Different milling speeds, feed per tooth, and axial depth of cut are used to explore the effects of the milling process parameters on the cutting temperature, cutting forces, and power required for machining. This model provides fundamental understanding of cutting mechanics of the 3D high speed milling of Titanium alloy (Ti-6Al-4V).

Research Progress of the Surface Oxidation of Titanium and its Alloys

2013 ◽  
Vol 748 ◽  
pp. 188-191
Author(s):  
Hui Jun Yu
Keyword(s):  
Titanium Alloys ◽  
Biomedical Applications ◽  
Influence Factors ◽  
Surface Oxidation ◽  
Research Progress ◽  
Corrosion Resistant ◽  
Specific Strength ◽  
Existing Problems ◽  
High Specific Strength ◽  
Micro Arc Oxidation

Titanium and titanium alloys possess some attractive properties, such as excellent corrosion and erosion resistance, low densities, high specific strength and modulus, enabling them extensively used in aeronautical, marine, chemical and biomedical applications and so on. Nevertheless, Recent years, the corrosion resistance of titanium and titanium alloys is required to elevate in some fields, proper surface modification such as surface oxidation can solve the problems effectively. In this paper, the recent investigations of thermal oxidation and micro-arc oxidation to improve the corrosion resistant of titanium and its alloys are reviewed. The structures, properties and their influence factors of the coatings are analysed systematically. And the existing problems and the future prospect of the further researches is mentioned.

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.

Experimental Study of Tool Wear during Quasi High Speed Turning Titanium Alloy with Large Cutting Depth

2014 ◽  
Vol 800-801 ◽  
pp. 548-552
Author(s):  
Li Fu Xu ◽  
Wei Liang Dong ◽  
Shu Tao Huang ◽  
Bao Lin Dai
Keyword(s):  
Experimental Data ◽  
Titanium Alloy ◽  
High Speed ◽  
Flank Wear ◽  
Rake Face ◽  
Cutting Depth ◽  
Tool Flank Wear ◽  
High Speed Turning ◽  
Flank Face ◽  
Cutting Speeds

The wear morphology of rake face and flank face of tool is investigated by turning titanium alloy TC4 with CBN solid tool. It has been observed that the main wear form of rake face and flank face of tool is groove wear. The relation between tool flank wear and cutting speeds, feed rate, and cutting depth obtained from experimental data is given.

The Influences of Cutting Speed on the Fatigue of Titanium Alloy

2007 ◽  
Vol 10-12 ◽  
pp. 742-746
Author(s):  
Guo Sheng Geng ◽  
Jiu Hua Xu
Keyword(s):  
Titanium Alloy ◽  
Electron Microscope ◽  
High Speed ◽  
Cutting Speed ◽  
Cyclic Stress ◽  
Fatigue Properties ◽  
Stress Strain ◽  
Ta15 Titanium Alloy ◽  
Cutting Speeds ◽  
Scanning Electron

This research is concerned with the influences of cutting speed on the fatigue properties of high speed milled Ti-6.5Al-2Zr-1Mo-1V (TA15) titanium alloy. Four different cutting speeds ranging from 50 to 200m/min were used to mill the specimens for fatigue test, and the fatigue properties of them were studied at two stress levels: 80—800MPa and 90—900MPa. The fatigue lives of the specimens milled under different cutting speeds were compared. The fracture surfaces were analyzed using scanning electron microscope (SEM), and cyclic stress-strain properties of TA15 titanium alloy were investigated with a stress-strain gauge. The results showed that increasing cutting speed can help to improve the fatigue properties of titanium alloy, especially at a relatively low cyclic stress level.

ATI 425® Alloy Formability: Theory and Application

2014 ◽  
Vol 783-786 ◽  
pp. 543-548 ◽  
Author(s):  
David Bryan
Keyword(s):  
Titanium Alloys ◽  
Elevated Temperatures ◽  
Thermomechanical Processing ◽  
Nominal Composition ◽  
Aerospace Applications ◽  
Beta Titanium ◽  
Alpha Beta ◽  
Cp Ti ◽  
Product Forms ◽  
Beta Titanium Alloys

ATI 425® Alloy, nominal composition Ti-4.0Al-2.5V-1.5Fe-0.25O, is a new alpha/beta Ti alloy of significant commercial interest as a viable replacement for Ti-6Al-4V, CP-Ti, and other titanium alloys in a variety of aerospace applications. ATI 425® Alloy offers properties comparable to Ti-6Al-4V alloy with significant improvements in formability, both at room and elevated temperatures. The reasons for the improved formability, particularly at low temperatures, are not well understood. The development of a thorough understanding is complicated by the wide array of phases, microstructures, and deformation paths available via thermomechanical processing in alpha/beta titanium alloys. In this paper, theories of strengthening and dislocation mobility in titanium and HCP metals will be reviewed and applied to better understand why ATI 425® Alloy offers a unique combination of strength and formability not obtainable by conventional alpha/beta titanium alloys. Subsequently, the application of the improved formability to a range of product forms including sheet, tubing, and forgings will be discussed.

On the Catastrophic Shear Instability in High-Speed Machining of an AISI 4340 Steel

1982 ◽  
Vol 104 (2) ◽  
pp. 121-131 ◽  
Author(s):  
R. Komanduri ◽  
T. Schroeder ◽  
J. Hazra ◽  
B. F. von Turkovich ◽  
D. G. Flom
Keyword(s):  
Titanium Alloys ◽  
Shear Zone ◽  
Chip Formation ◽  
High Speed ◽  
Shear Bands ◽  
Shear Instability ◽  
Aisi 4340 Steel ◽  
4340 Steel ◽  
Cutting Speeds ◽  
Aisi 4340

An AISI 4340 Steel (325 BHN) was machined at various speeds up to 2500 m/min (8000 SFPM). Longitudinal midsections of the chips were examined metallurgically to delineate the differences in the chip formation characteristics at various speeds. Chips were found to be continuous at 30 to 60 m/min (100 to 200 SFPM) but discontinuous below this speed. Instabilities in the cutting process, leading to different types of cyclic chip formations, were observed at cutting speeds above 60 m/min (200 SFPM). Fully developed catastrophic shear bands separated by large areas (segments) of relatively less deformed material, similar to that when machining titanium alloys, were observed in the chips at cutting speeds above 275 m/min (800 SFPM). The intense shear bands between the segments appeared to have formed subsequent to the localized intense deformation of the segment in the primary shear zone. As the cutting speed increases, the extent of contact between the segments is found to decrease rapidly. At speeds of 1000 m/min (3200 SFPM) and above, due to rapid intense, localized shear between the segments, these segments were found to separate completely as isolated segments instead of being held intact as a long chip. The speed at which this decohesion occurs was found to depend upon the metallurgical state of the steel machined and its hardness. As in the case of machining titanium alloys, the deformation of the chip as it slides on the tool face, i.e., “secondary shear zone,” appeared to be negligible when machining this AISI 4340 steel at high speed. Based on the metallurgical study of the chip and the similarities of machining this material at high speed and that of titanium alloys at normal speed, a cyclic phenomenon in the primary shear zone is identified as the source of instability responsible for the large-scale heterogeneity and a mechanism of chip formation when machining AISI 4340 steel at high speed is proposed.

Influence of the composition of α-titanium alloys on thermal conductivity

2021 ◽  
pp. 79-86
Author(s):  
I. A. Schastlivaya ◽  
V. P. Leonov ◽  
I. V. Tretyakov ◽  
A. Yu. Askinazi
Keyword(s):  
Thermal Conductivity ◽  
Titanium Alloys ◽  
Nuclear Power ◽  
Power Plants ◽  
Operating Temperature ◽  
Unique Combination ◽  
Specific Strength ◽  
High Specific Strength ◽  
Heat Exchange Equipment ◽  
Materials Used

Among titanium alloys, modern α- and pseudo-α-alloys occupy a special place due to the unique combination of their mechanical properties, corrosion resistance, low density and high specific strength, which determines their effectiveness in various industries. Analysis of structural materials used for heat exchange equipment of nuclear power plants showed that the increase in the efficiency and compactness of tube systems made of a-titanium alloys is constrained by their thermal conductivity characteristic, which does not exceed 89 W/(m·K) at a temperature of 20°C. An exception is the VT1-0 grade alloy, the scope of which is limited to a maximum operating temperature of no more than 250°C. The paper considers the results of studies of a new titanium alloy of the Ti-Zr-Al-O composition with increased thermal conductivity for pipe systems of power equipment. 

INCREASING THE RELIABILITY OF FRICTION UNITS MADE OF TITANIUM ALLOYS

2021 ◽  
Vol 1 (142) ◽  
pp. 100-106
Author(s):  
Egor O. Reshchikov ◽  
◽  
Il’ya V. Romanov ◽  
Roman N. Zadorozhniy ◽  
Keyword(s):  
Wear Resistance ◽  
Titanium Alloy ◽  
Titanium Alloys ◽  
Graphite Electrode ◽  
Research Purpose ◽  
High Wear Resistance ◽  
Specific Strength ◽  
Friction Units ◽  
Fluorescence Spectrometer

The most important advantages of titanium alloys over other structural materials are their high specific strength and heat resistance, combined with high corrosion resistance and low density. Despite all the positive characteristics of titanium alloys, their tribotechnical properties are very poor, which limits the use of these materials in moving joints. (Research purpose) The research purpose is in increasing the wear resistance and reliability of friction units made of titanium alloys by means of electric spark processing. (Materials and methods) For the study there was used samples of disks with a diameter of 60 and a thickness of 5 millimeters made of a hard alloy of the VT20 brand, an EIO "BIG-1M" installation, a Niton XL3t X-ray fluorescence spectrometer, a Surtronic profilometer, a TRB-S-DE-0000 tribometer, and an OLYMPUS GX51 microscope. (Results and discussion) Coatings were applied to samples made of titanium alloy by electric spark treatment with electrodes made of different materials. The tribotechnical characteristics of such coatings were studied in accordance with the ASTM G99 standard. It was found that the roughness of the samples after electric spark treatment significantly exceeds the roughness of the untreated sample. According to the results of the experiments, the most optimal electrode material was selected to increase the wear resistance of the surfaces of titanium alloys. The titanium alloy after electric spark treatment with a graphite electrode has a high wear resistance and a low coefficient of friction; graphite deposited on the surface of the sample does not form a strong coating, but plays the role of a solid lubricant that is gradually consumed during wear. (Conclusions) The surfaces obtained with the graphite electrode have the best wear resistance and the lowest friction coefficient.

Determining High-Temperature Oxidation Resistance of (TI-Al-X-N) Based Coatings for Titanium Alloys

2021 ◽  
Vol 320 ◽  
pp. 66-71
Author(s):  
Konstantins Savkovs ◽  
Margarita Urbaha ◽  
Viktors Feofanovs
Keyword(s):  
Titanium Alloys ◽  
Gas Turbine ◽  
Gas Turbine Engine ◽  
Resistance Testing ◽  
Maximum Efficiency ◽  
Temperature Oxidation ◽  
Turbine Engine ◽  
Specific Strength ◽  
High Specific Strength ◽  
Pressure Part

Basic titanium alloys are successfully used in modern aviation GTE (gas turbine engine). They are used for parts of a compressor and partly in low pressure part of turbine (intermetallic Ti-Al alloys) due to their high specific strength and at the same time low density, high corrosion resistance but can be used only up to 700 °C. The paper deals with the results of heat resistance testing at 750 °C of Ti-Al-(X)+N based thin ion-plasm multilayers coatings, with different priority of monolayers- intermetallic, conglomerate or nitride for gas turbine engine (GTE) blades from titanium alloys. All coatings showed high resistance during the test, with a maximum efficiency 42.8 of coating with a priority of conglomerate after 30 hours of testing.

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