Fatigue in Single Crystal Nickel Superalloys
Technical progress rept. 16 Apr-15 May 93,
PRATT AND WHITNEY WEST PALM BEACH FL GOVERNMENT ENGINES AND SPACE PROPULSION
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This program investigates the seemingly unusual behavior of single crystal airfoil materials. The fatigue initiation processes in single crystal SC materials are significantly more complicated and involved than fatigue initiation and subsequent behavior of a single macrocrack in conventional, isotropic, materials. To understand these differences it is helpful to review the evolution of high temperature airfoils. Modern gas turbine flight propulsion systems employ single crystal materials for turbine airfoil applications because of thier superior performance in resisting creep, oxidation, and thermal mechanical fatigue TMF. These properties have been achieved by composition and alloying, of course, but also by appropriate crystal orientation and associated anisotropy.
- Properties of Metals and Alloys