All I’d like to add is never confuse the application of materials used in piston driven aircraft propellers with the blades of a turbojet/fan engines. They are two totally different applications with two totally different requirements.

There is a hell of a lot more involved than cost.
Flex requirements. Vibration absorption/transfer. Gyroscopic issues. Power input/removal rates. Crankshaft power impulses. Torque/Leverage issues…..

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1980 300D - Veggie Burner !