Failure Mechanisms

· Turbine blades experience high tensile loading due to the engine rotation. Aerodynamic clearances need to be low, and creep is a major factor in blade life.
· High melting point metals are needed to reduce the effects of creep which depend on the reduced temperature (T/T_m). Nickel based alloys are used for current turbine blades.
· The control of alloy composition and microstructure is essential to obtaining optimum performance.
· The uniaxially solidified 'single crystal' turbine blade shown is an early example from Pratt and Whitney.