Materials
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The materials used in current gas turbines are very similar to the ones used originally. It is impossible to list the exact alloys used because they are a closely guarded trade secret, but the general materials are as follows:
-Low Pressure Compressor: Non ferromagnetic- usually an aluminum alloy.
-High Pressure Compressor: Ferromagnetic- usually a type of steel with a strengthening alloy.
-Combustion Chamber: A type of non-ferrous stainless steel.
-High Pressure and Low Pressure Turbines: All are non-ferrous stainless-steel alloys that vary as you go from high to low pressure. Factors to consider are temperature, blade length, and the loading of the blade roots (where the blades attach to the wheel).
In new generation engines-high bypass- more exotic materials are used, such as hastelloy (typically a nickel alloy).
For the high pressure turbines the alloys are secret. The fan sections were and are titanium, a low density material. It is very tough and ductile so it will bend in bird strikes but will not break causing catastrophic failure. In the recent past an even lighter material has been developed. We know it as aramid fibre. It is made up of layers of carbon fibres and graphite fibres in the form of a cloth-like material, impregnated with resins, and shaped into structural elements such as fan blades or controls (flight). Note that all shafts are ferromagnetic steel due to its ability to withstand high-torque loads.
-Low Pressure Compressor: Non ferromagnetic- usually an aluminum alloy.
-High Pressure Compressor: Ferromagnetic- usually a type of steel with a strengthening alloy.
-Combustion Chamber: A type of non-ferrous stainless steel.
-High Pressure and Low Pressure Turbines: All are non-ferrous stainless-steel alloys that vary as you go from high to low pressure. Factors to consider are temperature, blade length, and the loading of the blade roots (where the blades attach to the wheel).
In new generation engines-high bypass- more exotic materials are used, such as hastelloy (typically a nickel alloy).
For the high pressure turbines the alloys are secret. The fan sections were and are titanium, a low density material. It is very tough and ductile so it will bend in bird strikes but will not break causing catastrophic failure. In the recent past an even lighter material has been developed. We know it as aramid fibre. It is made up of layers of carbon fibres and graphite fibres in the form of a cloth-like material, impregnated with resins, and shaped into structural elements such as fan blades or controls (flight). Note that all shafts are ferromagnetic steel due to its ability to withstand high-torque loads.