Effect of γ′ content on the mechanical behavior of the WASPALOY alloy system

This article presents the research results of the effects of alloy chemistry, cooling rate and solution temperature on mechanical behavior, especially for the fatigue-crack growth of the WASPALOY alloy system. It is indicated that tensile strengths, both yield strength and ultimate tensile strength, increase with increasing Al+Ti content in the alloys. The solution temperature had almost no effect on the tensile properties of WASPALOY. Cooling rate showed almost no effect on the tensile properties of WASPALOY, but for the alloys with a higher Al+Ti content, the yield strength of the alloys was improved with increasing cooling rate. The increase in precipitation content tremendously improved the stress rupture life of the alloys. The fatigue-crack resistance of the alloys can be improved by increasing the strengthening precipitate volume fraction, in spite of the variation of the cooling rate. The crack growth rates were time-dependent, as expected. The growth rate increased with decreasing loading frequency. However, a higher precipitate content showed a lower time dependence.