Alloys-By-Design: Application to nickel-based single crystal superalloys

Design rules are proposed by which the compositions of nickel-based single crystal superalloys can be chosen systematically, using models for the most important characteristics: creep resistance, microstructural stability, castability, density and cost. Application of the rules allows the very large compositional space to be reduced to just a few ideal compositions, which are likely to be close to the optimal ones. The procedures have the potential to remove much of the traditional reliance placed upon empiricism and trial-and-error-based testing. It appears that trade-offs must be accepted, however; for example, the most creep-resistant alloys are more dense, more costly and more inherently susceptible to casting-related defects such as freckles during processing. Compositions suitable for both jet propulsion and land-based applications are proposed, for future experimental testing.