Ti-6Al-4V

Last updated

Ti-6Al-4V (UNS designation R56400), also sometimes called TC4, Ti64, [1] or ASTM Grade 5, is an alpha-beta titanium alloy with a high specific strength and excellent corrosion resistance. It is one of the most commonly used titanium alloys and is applied in a wide range of applications where low density and excellent corrosion resistance are necessary such as e.g. aerospace industry and biomechanical applications (implants and prostheses).

Contents

Studies of titanium alloys used in armors began in the 1950s at the Watertown Arsenal, which later became a part of the Army Research Laboratory. [2] [3]

A 1948 graduate of MIT, Stanley Abkowitz (1927-2017) was a pioneer in the titanium industry and is credited for the invention of the Ti-6Al-4V during his time at the US Army’s Watertown Arsenal Laboratory in the early 1950s. [4]

Titanium/Aluminum/Vanadium alloy was hailed as a major breakthrough with strategic military significance. It is the most commercially successful titanium alloy and is still in use today, having shaped numerous industrial and commercial applications. [5]

Increased use of titanium alloys as biomaterials is occurring due to their lower modulus, superior biocompatibility and enhanced corrosion resistance when compared to more conventional stainless steels and cobalt-based alloys. [6] These attractive properties were a driving force for the early introduction of α (cpTi) and α+β (Ti—6Al—4V) alloys as well as for the more recent development of new Ti-alloy compositions and orthopaedic metastable b titanium alloys. The latter possess enhanced biocompatibility, reduced elastic modulus, and superior strain-controlled and notch fatigue resistance. [7] However, the poor shear strength and wear resistance of titanium alloys have nevertheless limited their biomedical use. Although the wear resistance of b-Ti alloys has shown some improvement when compared to a#b alloys, the ultimate utility of orthopaedic titanium alloys as wear components will require a more complete fundamental understanding of the wear mechanisms involved.

Chemistry

(in wt. %) [8]

V Al Fe O C N H Y Ti Remainder EachRemainder Total
Min3.65.6------------------
Max6.78.7.2.08.08.019.008Balance.2.4

Physical and mechanical properties

One possible microstructure of Ti-6Al-4V alloy with equiaxed alpha grains and discontinuous beta phase Ti64 20s rub krolls rod crossection.png
One possible microstructure of Ti-6Al-4V alloy with equiaxed alpha grains and discontinuous beta phase

Ti-6Al-4V titanium alloy commonly exists in alpha, with hcp crystal structure, (SG : P63/mmc) and beta, with bcc crystal structure, (SG : Im-3m) phases. While mechanical properties are a function of the heat treatment condition of the alloy and can vary based upon properties, typical property ranges for well-processed Ti-6Al-4V are shown below. [9] [10] [11] Aluminum stabilizes the alpha phase, while vanadium stabilizes the beta phase. [12] [13]

DensityYoung's ModulusShear ModulusBulk ModulusPoisson's RatioTensile Yield StressTensile Ultimate StressHardnessUniform Elongation
Min4.429 g/cm3 (0.160 lb/cu in)104 GPa (15.1×10^6 psi)40 GPa (5.8×10^6 psi)96.8 GPa (14.0×10^6 psi)0.31880 MPa (128,000 psi)900 MPa (130,000 psi)36 Rockwell C (Typical)5%
Max4.512 g/cm3 (0.163 lb/cu in)113 GPa (16.4×10^6 psi)45 GPa (6.5×10^6 psi)153 GPa (22.2×10^6 psi)0.37920 MPa (133,000 psi)950 MPa (138,000 psi)--18%

Ti-6Al-4V has a very low thermal conductivity at room temperature of 6.7 to 7.5 W/m·K, [14] [15] which contributes to its relatively poor machinability. [15]

The alloy is vulnerable to cold dwell fatigue. [16] [17]

Heat treatment of Ti-6Al-4V

Mill anneal, duplex anneal, and solution treatment and aging heat treatment processes for Ti-6Al-4V. Exact times and temperatures will vary by manufacturer. Common Ti-6Al-4V Heat Treatment Processes.svg
Mill anneal, duplex anneal, and solution treatment and aging heat treatment processes for Ti-6Al-4V. Exact times and temperatures will vary by manufacturer.

Ti-6Al-4V is heat treated to vary the amounts of and microstructure of and phases in the alloy. The microstructure will vary significantly depending on the exact heat treatment and method of processing. Three common heat treatment processes are mill annealing, duplex annealing, and solution treating and aging. [18]

Applications

Specifications

Related Research Articles

<span class="mw-page-title-main">Stainless steel</span> Steel alloy resistant to corrosion

Stainless steel, also known as inox, corrosion-resistant steel (CRES) and rustless steel, is an alloy of iron that is resistant to rusting and corrosion. It contains iron with chromium and other elements such as molybdenum, carbon, nickel and nitrogen depending on its specific use and cost. Stainless steel's resistance to corrosion results from the 10.5%, or more, chromium content which forms a passive film that can protect the material and self-heal in the presence of oxygen.

<span class="mw-page-title-main">Titanium</span> Chemical element, symbol Ti and atomic number 22

Titanium is a chemical element; it has symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion in sea water, aqua regia, and chlorine.

Beryllium copper (BeCu), also known as copper beryllium (CuBe), beryllium bronze, and spring copper, is a copper alloy with 0.5–3% beryllium. Copper beryllium alloys are often used because of their high strength and good conductivity of both heat and electricity. It is used for its ductility, weldability in metalworking, and machining properties. It has many specialized applications in tools for hazardous environments, musical instruments, precision measurement devices, bullets, and some uses in the field of aerospace. Beryllium copper and other beryllium alloys are harmful carcinogens that present a toxic inhalation hazard during manufacturing.

Refractory metals are a class of metals that are extraordinarily resistant to heat and wear. The expression is mostly used in the context of materials science, metallurgy and engineering. The definition of which elements belong to this group differs. The most common definition includes five elements: two of the fifth period and three of the sixth period. They all share some properties, including a melting point above 2000 °C and high hardness at room temperature. They are chemically inert and have a relatively high density. Their high melting points make powder metallurgy the method of choice for fabricating components from these metals. Some of their applications include tools to work metals at high temperatures, wire filaments, casting molds, and chemical reaction vessels in corrosive environments. Partly due to the high melting point, refractory metals are stable against creep deformation to very high temperatures.

In modern Western body piercing, a wide variety of materials are used. Some cannot be autoclaved, and others may induce allergic reactions, or harbour bacteria. Certain countries, such as those belonging to the EU, have legal regulations specifying which materials can be used in new piercings.

Titanium alloys are alloys that contain a mixture of titanium and other chemical elements. Such alloys have very high tensile strength and toughness. They are light in weight, have extraordinary corrosion resistance and the ability to withstand extreme temperatures. However, the high cost of both raw materials and processing limit their use to military applications, aircraft, spacecraft, bicycles, medical devices, jewelry, highly stressed components such as connecting rods on expensive sports cars and some premium sports equipment and consumer electronics.

<span class="mw-page-title-main">Microstructure</span> Very small scale structure of material

Microstructure is the very small scale structure of a material, defined as the structure of a prepared surface of material as revealed by an optical microscope above 25× magnification. The microstructure of a material can strongly influence physical properties such as strength, toughness, ductility, hardness, corrosion resistance, high/low temperature behaviour or wear resistance. These properties in turn govern the application of these materials in industrial practice.

Titanium powder metallurgy (P/M) offers the possibility of creating net shape or near net shape parts without the material loss and cost associated with having to machine intricate components from wrought billet. Powders can be produced by the blended elemental technique or by pre-alloying and then consolidated by metal injection moulding, hot isostatic pressing, direct powder rolling or laser engineered net shaping.

Dr. Ramulu Mamidala is a mechanical engineering professor at University of Washington. Usually goes by the name 'Ram', or 'M.R.', he is recognized for his leadership and outstanding record in promoting collaborative education and research with industry. He is currently the director of Manufacturing Science and Technology Laboratory (MSTL) at Mechanical Engineering Department, University of Washington. He has designed and developed manufacturing methods for a wide range of systems, from the B2 bomber to the Boeing 787. Additionally, in collaboration with industry, he established and directed two interdisciplinary graduate educational programs in engineering and management and a certificate program in composites tooling and manufacturing. His exemplary collaborative efforts motivated working engineers to pursue doctoral studies and he is a leader in using emerging technologies in distance education to reach non-traditional students.

<span class="mw-page-title-main">Aluminium alloy</span> Alloy in which aluminium is the predominant metal

An aluminium alloy (UK/IUPAC) or aluminum alloy is an alloy in which aluminium (Al) is the predominant metal. The typical alloying elements are copper, magnesium, manganese, silicon, tin, nickel and zinc. There are two principal classifications, namely casting alloys and wrought alloys, both of which are further subdivided into the categories heat-treatable and non-heat-treatable. About 85% of aluminium is used for wrought products, for example rolled plate, foils and extrusions. Cast aluminium alloys yield cost-effective products due to the low melting point, although they generally have lower tensile strengths than wrought alloys. The most important cast aluminium alloy system is Al–Si, where the high levels of silicon (4–13%) contribute to give good casting characteristics. Aluminium alloys are widely used in engineering structures and components where light weight or corrosion resistance is required.

6061 aluminium alloy is a precipitation-hardened aluminium alloy, containing magnesium and silicon as its major alloying elements. Originally called "Alloy 61S", it was developed in 1935. It has good mechanical properties, exhibits good weldability, and is very commonly extruded. It is one of the most common alloys of aluminium for general-purpose use.

7075 aluminium alloy (AA7075) is an aluminium alloy with zinc as the primary alloying element. It has excellent mechanical properties and exhibits good ductility, high strength, toughness, and good resistance to fatigue. It is more susceptible to embrittlement than many other aluminium alloys because of microsegregation, but has significantly better corrosion resistance than the alloys from the 2000 series. It is one of the most commonly used aluminium alloys for highly stressed structural applications and has been extensively used in aircraft structural parts.

In metallurgy, solid solution strengthening is a type of alloying that can be used to improve the strength of a pure metal. The technique works by adding atoms of one element to the crystalline lattice of another element, forming a solid solution. The local nonuniformity in the lattice due to the alloying element makes plastic deformation more difficult by impeding dislocation motion through stress fields. In contrast, alloying beyond the solubility limit can form a second phase, leading to strengthening via other mechanisms.

Titanium Beta C refers to Ti Beta-C, a trademark for an alloy of titanium originally filed by RTI International. It is a metastable "beta alloy" which was originally developed in the 1960s; Ti-3Al-8V-6Cr-4Mo-4Zr, nominally 3% aluminum, 8% vanadium, 6% chromium, 4% molybdenum, 4% zirconium and balance (75%): titanium.

An Electrochemical Fatigue Crack Sensor (EFCS) is a type of low cost electrochemical nondestructive dynamic testing method used primarily in the aerospace and transportation infrastructure industries. The method is used to locate surface-breaking and slightly subsurface defects in all metallic materials. In bridge structures, EFCS is used at known fatigue susceptible areas, such as sharp-angled coped beams, stringer to beam attachments, and the toe of welds. This dynamic testing can be a form of short term or long-term monitoring, as long as the structure is undergoing dynamic cyclic loading.

Ti-6Al-2Sn-4Zr-2Mo, also known as Ti 6-2-4-2, is a near alpha titanium alloy known for its high strength and excellent corrosion resistance. It is often used in the aerospace industry for creating high-temperature jet engines and the automotive industry to create high performance automotive valves.

<span class="mw-page-title-main">Inconel 625</span> Nickel-based superalloy

Inconel Alloy 625 is a nickel-based superalloy that possesses high strength properties and resistance to elevated temperatures. It also demonstrates remarkable protection against corrosion and oxidation. Its ability to withstand high stress and a wide range of temperatures, both in and out of water, as well as being able to resist corrosion while being exposed to highly acidic environments makes it a fitting choice for nuclear and marine applications.

Ti-6Al-7Nb is an alpha-beta titanium alloy first synthesized in 1977 containing 6% aluminum and 7% niobium. It features high strength and has similar properties as the cytotoxic vanadium containing alloy Ti-6Al-4V. Ti-6Al-7Nb is used as a material for hip prostheses.

Titanium adhesive bonding is an engineering process used in the aerospace industry, medical-device manufacture and elsewhere. Titanium alloy is often used in medical and military applications because of its strength, weight, and corrosion resistance characteristics. In implantable medical devices, titanium is used because of its biocompatibility and its passive, stable oxide layer. Also, titanium allergies are rare and in those cases mitigations like Parylene coating are used. In the aerospace industry titanium is often bonded to save cost, touch times, and the need for mechanical fasteners. In the past, Russian submarines' hulls were completely made of titanium because the non-magnetic nature of the material went undetected by the defense technology at that time. Bonding adhesive to titanium requires preparing the surface beforehand, and there is not a single solution for all applications. For example, etchant and chemical methods are not biocompatible and cannot be employed when the device will come into contact with blood and tissue. Mechanical surface roughness techniques like sanding and laser roughening may make the surface brittle and create micro-hardness regions that would not be suitable for cyclic loading found in military applications. Air oxidation at high temperatures will produce a crystalline oxide layer at a lower investment cost, but the increased temperatures can deform precision parts. The type of adhesive, thermosetting or thermoplastic, and curing methods are also factors in titanium bonding because of the adhesive's interaction with the treated oxide layer. Surface treatments can also be combined. For example, a grit blast process can be followed by a chemical etch and a primer application.

Aluminium 7050 alloy is a heat treatable alloy. It has high toughness, high strength. It has high stress corrosion cracking resistance. It has electric conductivity of value having 40 percent of copper. 7050 aluminium is known as a commercial aerospace alloy.

References

  1. ↑ Paul K. Chu; XinPei Lu (15 July 2013). Low Temperature Plasma Technology: Methods and Applications. CRC Press. p. 455. ISBN   978-1-4665-0991-7.
  2. ↑ "Founding of ARL". www.arl. army.mil. Army Research Laboratory. Retrieved 6 June 2018.
  3. ↑ Gooch, William A. "The Design and Application of Titanium Alloys to U.S. Army Platforms -2010" (PDF). U.S. Army Research Laboratory. Retrieved 6 June 2018.
  4. ↑ "Stan Abkowitz, '48 – MIT Technology Review". 18 October 2016.
  5. ↑ "Stanley Abkowitz, 90; Titanium Industry Pioneer - International Titanium Association".
  6. ↑ Long, M.; Rack, H.J. (1998). "Titanium alloys in total joint replacement—a materials science perspective". Biomaterials. 18 (19): 1621–1639. doi:10.1016/S0142-9612(97)00146-4. PMID   9839998.
  7. ↑ Gutmanas, E.Y.; Gotman, I. (2004). "PIRAC Ti nitride coated Ti–6Al–4V head against UHMWPE acetabular cup–hip wear simulator study". Journal of Materials Science: Materials in Medicine. 15 (4): 327–330. doi:10.1023/B:JMSM.0000021096.77850.c5. PMID   15332594. S2CID   45437647.
  8. ↑ Standard Specification for Wrought Titanium-6Aluminum-4Vanadium Alloy for Surgical Implant Applications (UNS R56400)
  9. ↑ "Titanium Ti-6Al-4V (Grade 5), Annealed". asm.matweb.com. ASM Aerospace Specification Metals, Inc. Retrieved 14 March 2017.
  10. ↑ "Titanium Alloy Ti 6Al-4V Technical Data Sheet". cartech.com. Carpenter Technology Corporation. Retrieved 14 March 2017.
  11. ↑ "AZoM Become a Member Search... Search Menu Properties This article has property data, click to view Titanium Alloys - Ti6Al4V Grade 5". www.azom.com. AZO Materials. 30 July 2002. Retrieved 14 March 2017.
  12. ↑ Wanhill, Russell; Barter, Simon (2012), "Metallurgy and Microstructure", Fatigue of Beta Processed and Beta Heat-treated Titanium Alloys, Springer Netherlands, pp. 5–10, doi:10.1007/978-94-007-2524-9_2, ISBN   9789400725232
  13. ↑ Donachie, Matthew J. (2000). Titanium : a technical guide (2nd ed.). Materials Park, OH: ASM International. pp.  13–15. ISBN   9781615030620. OCLC   713840154.
  14. ↑ "ASM Material Data Sheet". asm.matweb.com. Retrieved 2020-06-20.
  15. 1 2 Yang, Xiaoping; Liu, C. Richard (1999-01-01). "Machining Titanium and Its Alloys". Machining Science and Technology. 3 (1): 107–139. doi:10.1080/10940349908945686. ISSN   1091-0344.
  16. ↑ BEA (September 2020). "AF066 crash investigation results" (PDF).
  17. ↑ Pilchak, Adam L.; Hutson, Alisha; Porter, W. John; Buchanan, Dennis; John, Reji (2016). "On the Cyclic Fatigue and Dwell Fatigue Crack Growth Response of Ti-6Al-4V". Proceedings of the 13th World Conference on Titanium. pp. 993–998. doi:10.1002/9781119296126.ch169. ISBN   9781119296126.
  18. ↑ ASM Committee (2000). "The Metallurgy of Titanium". Titanium: A Technical Guide. ASM International. pp. 22–23.
  19. ↑ Hawk, Jeff (May 25, 2005). The Boeing 787 Dreamliner: More Than an Airplane (PDF). AIAA/AAAF Aircraft Noise and Emissions Reduction Symposium. American Institute of Aeronautics and Astronautics . Archived from the original (PDF) on August 8, 2007. Retrieved July 15, 2007.
  20. ↑ Guy Hellard (2008). "Composites in Airbus - A Long Story of Innovations and Experiences" (PDF). Global Investor Forum. Airbus. Archived from the original (PDF) on 4 October 2016. Retrieved 30 January 2019.
  21. ↑ "Ti6Al4V Titanium Alloy" (PDF). Arcam. Archived from the original (PDF) on 2020-02-15. Retrieved 2015-12-16.
  22. ↑ "Ti64 Titanium Alloy Powder". Tekna.
  23. ↑ SAE AMS4928W, Titanium Alloy Bars, Wire, Forgings, Rings, and Drawn Shapes 6Al - 4V Annealed, Warrendale, PA: SAE International, retrieved 28 September 2022
  24. ↑ "§1.1.5", ASTM B265-20a, Standard Specification for Titanium and Titanium Alloy Strip, Sheet, and Plate, West Conshohocken, PA: ASTM International, 2020, doi:10.1520/B0265-20A , retrieved 13 August 2020
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.