The Effect of Casting Variables and Section Size on the Stress-Rupture Life of a High Temperature Nickel Base Alloy

A study was conducted to determine the effect of the many foundry variables, inherent in the investment casting industry, on the stress-rupture life of Lycoming alloy M3608-a representative state-of-the-art nickel base superalloy. Particular emphasis was placed on the roll of test specimen geometry and its relationship to cast turbine blade hardware. Trends are discussed in terms of rupture life, microstructure, and microdiscontinuities.

Knowledge of the effect of casting parameters and component section size on rupture life will enable the designer and materials engineer to design and fabricate new hardware with greater assurance that it will do the job intended.