turbine blade alloys

Question 1

Principle of propulsion

Answer 1

• accelerate a mass of gas by extracting energy by burning fuel, and the resultant change in momentum provides forward thrust
• Propeller aircraft take a large mass of gas and impart moderate acceleration
• turbojets take a small mass of gas and impart high acceleration.

Question 2

Turbine materials

Answer 2

-high pressure

Question 3

Evolution of Ni-based superalloy turbine blades

Answer 3

1. alloy development
2. processing
3. blade cooling
4. alloy development
5. coatings
6. novel processing

Question 4

Investment casting

Answer 4

• vacuum process, reduces oxide contamination
• huge advances in process cleanliness made past 30 years
• controlled cooling(directional solidification)
• cooling channels cast into blade
• blades heat treated

Question 5

liquid metal cooling

Answer 5

• improves micro structures

- faster solidification (higher throughout and reduced costs)