Stress Rupture Behavior of a Dispersion Strengthened Superalloy

A dispersion strengthened nickel-base superalloy, designated IN-853, has been made by a new process called “Mechanical Alloying.” This provides a long sought combination of properties typical of dispersion strengthened and precipitation hardened materials. The alloy has flat rupture curves over a wide temperature range. Rupture stress/temperature curves for the alloy show a transition separating the low temperature regime where precipitation hardening controls the strength, and the high temperature range where dispersion strengthening predominates. The slope of a Larson-Miller plot of stress rupture test data also decreases at high values of that parameter. At high temperatures rupture stress is less sensitive to temperature changes than is the case with conventional nickel-base superalloys. At a fixed stress level the rupture life of the dispersion strengthened superalloy is more sensitive to temperature changes.