IN-853 is a nickel-base alloy which combines precipitation hardening at low and intermediate temperatures (≲ 1400 F) and dispersion strengthening by Y2O3 at elevated temperatures (≳ 1400 F) with good oxidation resistance.
Rotating beam fatigue tests were conducted in air on IN-853 at room temperature, 1000, 1400, and 1750 F, and on a conventional superalloy with a composition close to that of the IN-853 matrix at room temperature, 1000 and 1400 F. Axial fatigue tests were also conducted on IN-853 at room temperature and 1400 F for minimum stress/maximum stress ratios of +0.1 and -1.0.
At testing temperatures up to 1400 F the 107 cycle fatigue strength of IN-853 was higher than that of the conventional superalloy. At 1750 F the fatigue strength of IN-853 was greater than the ultimate tensile strength measured in a standard (low strain rate) tension test at this temperature.
The modes of crack propagation and fracture have been determined using optical metallography and transmission electron microscopy. The effects of γ́ precipitate, Y2O3 dispersoid, carbides, and grain boundaries on the fatigue damage and failure are presented.