The LP compressor blades, or fan blades, are those blades that you can see at the front of the engine. These blades must be strong enough so as not to break up if the engine ingests a bird. Engine bird strikes can do immense damage to the engine, causing a complete failure if the compressor blades break up, and for this reason the blades are made from titanium.
This is where the second stage of air compression takes place. Heat caused by compression comes into effect, but not the extreme heat experienced in the turbine. The high-pressure compressor blades are either made from titanium or in some cases from a nickel alloy.
This is where the compressed air and fuel are mixed, ignited and burned. Because of the high temperatures experienced here, heat-resistant nickel alloys are most commonly used in their construction. The fuel injector stems are usually made from a nickel alloy called Inconel 625 because of its high strength and its ability to withstand high temperatures.
The turbine blades must be able to take the brunt of the pounding of a mixture of very high pressure and temperature together, and they are made from a material called single-crystal nickel. This is formed by a very special process in which the metal grains in the blade are lined up parallel to the blade by a process called directional solidifying.
The cowling is the exterior part of the aircraft engine, which must by aerodynamically shaped and at the same time as light as possible. It does not have to put up with extremes of pressure and temperature and is made up from molded aluminum sheeting. More and more composites are being used in new designs of aircraft engines, especially Kevlar.
