General Information
Titanium is a white metal, and has the best strength to weight ratio among the metals. Titanium is very reactive, and because of this it is often used for alloying and deoxidizing other metals. Titanium is a more powerful deoxidizer of steel than silicon or manganese. Titanium is 40% lighter than steel and 60% heavier than aluminum. This combination of high strength and low weight makes titanium a very useful structural metal. Titanium also features excellent corrosion resistance, which stems from a thin oxide surface film which protects it from atmospheric and ocean conditions as well as a wide variety of chemicals.
Fabrication
Titanium is rather difficult to fabricate because of its susceptibility to oxygen, nitrogen, and hydrogen impurities which cause the titanium to become more brittle. Elevated temperature processing must be used under special conditions in order to avoid diffusion of these gasses into the titanium. Commercially produced titanium products are made in the following mill wrought forms; plate, tubing, sheet, wire, extrusions, and forgings. Titanium can also be cast, which must be done in a vacuum furnace because of titanium's reactive nature.
Applications
Because of its high strength to weight ratio, titanium is used in a variety of applications, including products where weight is of importance such as aircraft, sporting equipment, etc.. Because of its excellent corrosion resistance, titanium is also used for chemical processing, desalination, power generation equipment, valve and pump parts, marine hardware, and prosthetic devices.
Grades
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Commercially Pure Alloys:
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There are five grades of what is known as
commercially pure or unalloyed titanium, ASTM Grades 1 through 4, and 7. Each
grade has a different amount of impurity content, with Grade 1 being the most
pure. Tensile strengths vary from 172 MPa for Grade 1 to 483 MPa for Grade 4.
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Alpha Alloys:
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Titanium alpha alloys are alloys that
typically contain aluminum and tin, though they can also contain molybdenum,
zirconium, nitrogen, vanadium, columbium, tantalum, and silicon. Alpha alloys
do not generally respond to heat treatment, but they are weldable and are
commonly used for cryogenic applications, airplane parts, and chemical
processing equipment.
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Alpha-Beta Alloys:
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Alpha-beta alloys can be strengthened by heat
treatment and aging, and therefore can undergo manufacturing while the
material is still ductile, then undergo heat treatment to strengthen the
material, which is a big advantage. The alloys are used in aircraft and
aircraft turbine parts, chemical processing equipment, marine hardware, and
prosthetic devices.
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Beta Alloys:
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The smallest group of titanium alloys, beta
alloys have good hardenability, good cold formability when they are
solution-treated, and high strength when they are aged. Beta alloys are
slightly more dense than other titanium alloys, having densities ranging from
4840 to 5060 kg/m3. They are the least creep resistant alloys,
they are weldable, and can have yield strengths up to 1345 MPa. They are used
for heavier duty purposes on aircraft.
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Typical Physical/Mechanical Properties
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Density: | 4510 kg/m3 |
Melting Point: | 1668 °C |
Elastic Modulus: | 100-120 GPa |
Poisson's Ratio: | 0.33 |
Tensile Strength: | 234 MPa |
Yield Strength: | 138 MPa |
Percent Elongation: | 54% |
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Thermal Expansion Coefficient: | 8-10 × 10-6/K |
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Titanium Alloy |
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Name
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Purpose
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Grade
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99.0
Ti
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Wrought
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Commercially
Pure
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99.1
Ti
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Wrought
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Commercially
Pure
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99.2
Ti
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Wrought
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Commercially
Pure
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99.2Ti-0.2Pd
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Wrought
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Commercially
Pure
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99.5
Ti
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Wrought
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Commercially
Pure
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Ti-0.3Mo-0.8Ni
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Wrought
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Commercially
Pure
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Ti-10V-2Fe-3Al
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Wrought
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Alpha-beta
alloy
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Ti-11.5Mo-6Zr-4.5Sn
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Wrought
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Beta
alloy
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Ti-13V-11Cr-3Al
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Wrought
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Beta
alloy
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Ti-2.25-Al-11Sn-5Zr-1Mo-0.2Si
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Wrought
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Near
alpha alloy
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Ti-3Al-2.5V
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Wrought
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Alpha-beta
alloy
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Ti-3Al-8V-6Cr-4Mo-4Zr
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Wrought
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Beta
alloy
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Ti-5AI-2Sn-2Zr-4Mo-4Cr
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Wrought
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Alpha-beta
alloy
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Ti-5Al-2.5Sn
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Wrought
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Alpha
alloy
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Ti-5Al-2.5Sn-ELI
(low O2)
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Wrought
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Alpha
alloy
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Ti-5Al-5Sn-2Zr-2Mo-0.25Si
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Wrought
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Near
alpha alloy
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Ti-6Al-2Nb-1Ta-1Mo
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Wrought
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Near
alpha alloy
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Ti-6Al-2Sn-2Zr-2Mo-2Cr-0.25Si
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Wrought
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Alpha-beta
alloy
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Ti-6Al-2Sn-4Zr-2Mo
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Wrought
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Near
alpha alloy
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Ti-6Al-2Sn-4Zr-6Mo
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Wrought
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Alpha-beta
alloy
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Ti-6Al-2Sn-l.5Zr-1Mo-0.35Bi-0.1Si
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Wrought
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Near
alpha alloy
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Ti-6Al-4V
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Wrought
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Alpha-beta
alloy
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Ti-6Al-4V-ELI
(low O2)
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Wrought
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Alpha-beta
alloy
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Ti-6Al-6V-2Sn-0.75Cu
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Wrought
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Alpha-beta
alloy
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Ti-7AI-4Mo
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Wrought
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Alpha-beta
alloy
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Ti-8Al-1Mo-1V
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Wrought
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Near
alpha alloy
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Ti-8Mn
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Wrought
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Alpha-beta
alloy
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Ti-8Mo-8V-2Fe-3Al
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Wrought
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Beta
alloy
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