Jet engines work at a higher temperature that the melting point of Titanium Superalloy so how do they not melt?
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As others have said, the high pressure turbine blades have air passing through them, and they are usually made of Inconel, a nickel based alloy.
Not to mention , the blade is not directly in the flame, but some way down stream of it (in context of an engine). So it is not in the hottest part of the engine. Engineers spend a lot of time working on the shape of the flame as well to stop it touching the side of the combustion chamber. Sometimes things block and you end up with a misshapen flame that melts things it’s not supposed to.
Metallurgy and an extremely clever manipulation of airflow through the engine to cool the blades
From the jet fuel? They aren’t made of steel beam.
I was responsible for the initial melting process of this component. The nickel based alloy goes through a rigorous triple melt process. VIM melting (void of atmosphere) , VAR and ESR remelting takes place after initial melt. Add in heat processing and very strict inspection process downstream.
2 things: Cooling and alloy. As the others have stated, air is bled from the “cold” side and used to cool the turbine blades. They are made of a nickel super alloy that is one single crystal and can withstand temperatures in excess of 1000 degrees celcius.
Mentioned here but wanted to reiterate, modern turbine blades are usually a single crystal. There are no crystal boundaries that could cause a fracture to propagate. Kinda mind blowing that we humans figured out how to do that and mass produce it. In CFM’s Leap engine they are ceramic.
The flame from the combustion chamber does not touch metal. A great majority of air that goes into the combustion chamber is called cooling air. By the time it reaches the turbine blades it is not nearly as hot as the flame. if you see flames shooting out of the back of a jet engine, without an afterburner, it is melting.
this fellow on youtube has a bunch of great videos about turbine engines
https://www.youtube.com/@AgentJayZ/videos
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