Titanium Alloys for Aeroengine and Airframe Applications

Topics Covered

Background

Aircraft Engines

Airframes

Titanium Alloys for Aircraft Applications

Background

The high strength and low density of titanium and its alloys have from the first ensured a positive role for the metal in aero-engine and airframe applications. It is difficult to imagine how current levels of performance, engine power to weight ratios, airframe strength, aircraft speed and range and other critical factors could be achieved without titanium.

Aircraft Engines

Titanium alloys capable of operating at temperatures from sub zero to 600°C are used in engines for discs, blades, shafts and casings from the front fan to the last stage of the high pressure compressor, and at the rear end of the engine for lightly loaded fabrications such as plug and nozzle assemblies.

Airframes

Alloys with strength up to 1200MPa are used in a wide variety of airframe applications from small fasteners weighing a few grams to landing gear trucks and large wing beams weighing up to 1 ton. Currently titanium makes up to 10% of empty weight of aircraft such as the Boeing 777.

Titanium Alloys for Aircraft Applications

Some of the alloys available for aircraft applications are outlined in the following tables. The alloys are grouped by their ralative usages.

Table 1. More widely used titanium alloys in aircraft applications.

Alloy

Attributes/Applications

Ti6Al4V

Workhorse, general purpose high strength alloy

Ti6Al2Sn4Zr2Mo (6-2-4-2)

Creep and oxidation resistant engine alloy

Ti6Al2Sn4Zr6Mo (6-2-4-6)

Creep and oxidation resistant engine alloy

Ti3Al8V6Cr4Zr4Mo (Beta C)

Beta alloy with established spring applications

Ti10V2Fe3Al (10-2-3)

Beta forging alloy used for 777 landing gear

Ti15V3Cr3Sn3Al (15-3-3-3)

High strength heat treatable beta sheet alloy

Ti3Al2.5V

Medium strength alloy used for hydraulic tubing

Ti4Al4Mo2Sn (550)

Higher strength heat treatable airframe and engine alloy

Ti5.5Al3.5Sn3Zr1Nb (829)

Advanced engine alloy, creep and oxidation resistant

Ti5.8Al4Sn3.5Zr0.7Nb (834)

Advanced engine alloy, creep and oxidation resistant

Ti5Al2Sn4Mo2Zr4Cr (Ti17)

Advanced engine alloy, creep and oxidation resistant

Ti15Mo3Nb3Al0.2Si (21S)

Oxidation and corrosion resistant beta sheet alloy

Table 2. Titanium alloys of increasing importance in aircraft applications.

Alloy

Attributes/Applications

Ti6Al2Zr2Sn2Mo2Cr0.25Si (6.22.22)

Airframe alloy for F22 and JSF projects

Ti4.5Al4Mo4Sn0.5Si (SP 700)

Competitor for Ti6Al4V for SPF and general use

Table 3. Less widely used titanium alloys in aircraft applications, but alloys that may be critical in their application to specific fully validated components.

Alloy

Attributes/Applications

Ti2Cu

Heat treatable sheet alloy

Ti4Al4Mo4Sno.5Si (551)

High strength airframe alloy, very limited availability

Ti8Al1Mo1V

Early alloy now mainly used for spares and replacements

Ti-6-6-2

High strength alloy with specific earlier applications

Ti11Sn5Zr2.5Al1Mo0.2Si (679)

Earlier engine alloy rarely specified in new programmes

Ti6Al5Zr0.5MoO.25Si (685)

Engine alloy now mainly for spares and replacements

 

Source: Titanium Information Group

 

For more information on this source please visit Titanium Information Group.

 

Date Added: Aug 13, 2002 | Updated: Jun 11, 2013
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