Use of titanium and titanium alloys started in the early
1950s. Soon, it becomes very popular with the aerospace, energy, and
chemical industries around the globe. Titanium and its alloys are the best
material choice for various critical applications because of their high
strength-to-weight ratio, excellent mechanical properties, and corrosion
resistance features. Titanium alloys are used for many critical hi-tech
applications, such as rotating and static gas turbine engine components and
parts of aircraft engines.
Other application areas of titanium alloys are :
| Nuclear power plants |
Food processing plants |
Oil refinery heat exchangers |
| Marine components |
Medical protheses |
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Almost 80% of all the titanium produced worldwide is used in the aerospace
industries.
Buying
Tips
Dimensions, performance features, and production processes are
three things that should be analyzed properly before selecting
titanium and titanium alloys.
- Dimensions: Outer diameter (OD), inner diameter (ID), overall
length, and overall thickness are important dimensions.
- Performance features: It include resistance to corrosion,
heat, and wear.
- Production processes: Most materials are cast, wrought,
extruded, forged, cold-finished, hot-rolled, or formed by
compacting powdered metals or alloys.
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Advantages of Titanium Alloys
Titanium is a light, strong, lustrous, corrosion-resistant transition
nonferrous metal. It can be easily alloyed with other elements/metals
including iron, aluminum, vanadium, molybdenum and others, for producing
strong lightweight alloys for aerospace and other demanding applications.
Titanium's advantages can be summarized as follows:
- Elevated temperature 350°F-1000°F service capability
- Excellent fatigue and fracture resistance
- Excellent strength-to-weight ratio
- Compatibility with carbon/epoxy materials
- It is used as part of the containers of batteries and as anode in
alkaline batteries.
- Biocompatibility
- Superior oxidation and corrosion resistance
- Non-magnetic character
- Fire resistance
- Short radioactive half life
Types of Titanium Alloys
Titanium alloys are classified as Alpha (a), Alpha-Beta (a-ß), and
Beta (ß) alloys on the basis of alloying elements they contain. The
following table explains and compares these three titanium alloys:
| Alpha Alloys (a) |
Alpha-Beta Alloys (a-ß)
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Beta Alloys (ß)
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| Alpha alloys commonly have
creep resistance superior to beta alloys. Alpha alloys are suitable
for somewhat elevated temperature applications. They are also
sometimes used for cryogenic applications. Alpha alloys have
adequate strength, toughness, and weldability for various
applications, but are not as readily forged as many beta alloys.
Alpha alloys cannot be strengthened by heat treatment. |
Alpha-Beta alloys have
chemical compositions that result in a mixture of alpha and beta
phases. The beta phase is normally in the range of 10 to 50% at room
temperature. Alloys with beta contents less than 20% are weldable.
The most commonly used titanium alloy is Ti-6Al-4V, an alpha + beta
alloy. While Ti-6Al-4V is fairly difficult to form other alpha +
beta alloys normally have better formability. |
Beta alloys have good
forging capability. Beta alloy sheet is cold formable when in the
solution treated condition. Beta alloys are prone to a ductile to
brittle transition temperature. Beta alloys can be strengthened by
heat treatment. Typically beta alloys are solutioned followed by
aging to form finely dispersed particles in a beta phase matrix. |
Followings are the few common titanium alloys according to the above
classifications:
| Alpha Alloys (a) |
Alpha-Beta Alloys (a-ß) |
Beta Alloys (ß) |
| Ti-2.5Cu |
Ti-6Al-4V |
Ti-13V-11Cr-3Al |
| Ti-5Al-2.5Sn |
Ti-6Al-6V-2Sn |
Ti-8Mo-8V-2Fe-3Al |
| Ti-8Al-1V-1Mo |
Ti-6Al-2Sn-2Zr-2Cr-2Mo |
Ti-10V-2Fe-3Al |
| Ti-6242 |
Ti-3Al-2.5V |
Ti-15-3 |
| Ti-6Al-2Nb-1Ta-0.8 Mo |
Ti-8Al-1Mo-1V |
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| Ti-5Al-5Sn-2Zr-2Mo |
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