Titanium Alloy

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

Commercially Pure Alloys: 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. Alpha Alloys: 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. Alpha-Beta Alloys: 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. Beta Alloys: 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.

Typical Physical/Mechanical Properties

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%

Typical Thermal Properties

Thermal Expansion Coefficient: 8-10 × 10-6/K

Titanium Alloy
Name Purpose Grade 99.0 Ti Wrought Commercially Pure 99.1 Ti Wrought Commercially Pure 99.2 Ti Wrought Commercially Pure 99.2Ti-0.2Pd Wrought Commercially Pure 99.5 Ti Wrought Commercially Pure Ti-0.3Mo-0.8Ni Wrought Commercially Pure Ti-10V-2Fe-3Al Wrought Alpha-beta alloy Ti-11.5Mo-6Zr-4.5Sn Wrought Beta alloy Ti-13V-11Cr-3Al Wrought Beta alloy Ti-2.25-Al-11Sn-5Zr-1Mo-0.2Si Wrought Near alpha alloy Ti-3Al-2.5V Wrought Alpha-beta alloy Ti-3Al-8V-6Cr-4Mo-4Zr Wrought Beta alloy Ti-5AI-2Sn-2Zr-4Mo-4Cr Wrought Alpha-beta alloy Ti-5Al-2.5Sn Wrought Alpha alloy Ti-5Al-2.5Sn-ELI (low O2) Wrought Alpha alloy Ti-5Al-5Sn-2Zr-2Mo-0.25Si Wrought Near alpha alloy Ti-6Al-2Nb-1Ta-1Mo Wrought Near alpha alloy Ti-6Al-2Sn-2Zr-2Mo-2Cr-0.25Si Wrought Alpha-beta alloy Ti-6Al-2Sn-4Zr-2Mo Wrought Near alpha alloy Ti-6Al-2Sn-4Zr-6Mo Wrought Alpha-beta alloy Ti-6Al-2Sn-l.5Zr-1Mo-0.35Bi-0.1Si Wrought Near alpha alloy Ti-6Al-4V Wrought Alpha-beta alloy Ti-6Al-4V-ELI (low O2) Wrought Alpha-beta alloy Ti-6Al-6V-2Sn-0.75Cu Wrought Alpha-beta alloy Ti-7AI-4Mo Wrought Alpha-beta alloy Ti-8Al-1Mo-1V Wrought Near alpha alloy Ti-8Mn Wrought Alpha-beta alloy Ti-8Mo-8V-2Fe-3Al Wrought Beta alloy