Turbine Blade

Turbine Blade. BBC How to Build A jumbo Jet Engine.

Turbine Blade. 96 turbine blades. The blade exists in a harsh environment, it has to rotate about 10000 R.P.M. The components itself operates at 300 degree above the melting point of the alloy.

Jet engines work by sucking air into the core and through multiple-compressors. Squashed to a 50th of its volume, this air is forced into the combustion  chamber where it explodes with the fuel to create a ferocious gas jet.  This jet is met head on by the turbine blades spinning them so fast that each blade delivers the same horsepower as the Formula One engine.

The bottom of the blade is fir tree area which held the blade into the disc. You can see aerofoils with the peppering of cooling holes.

Grain Boundary

If you take a normal piece of metal and solidify it from being molten. Lots of different crystals all in different directions. That's not very strong. Because the joins and the boundaries between crystals cause weakness. So they aim to do is create a single crystal. Single crystal, no crystal boundaries. Therefore, it's awful stronger. The blade is made by growing a single crystal of metal into the correct shape.

The secret part is the way the molten metal is cooled  through a spiral tube at the base of the mold. The tube prevents all but one crystal of solid metal from passing through. Allowing that single crystal to grow throughout the mold.