Effect of microstructure on fatigue strangth of an oxide dispersion strengthened ni-base superalloy at high temperature

摘要

The effect of microstructure relevantto thermo-mechanical treatments on the fatiguestrength in an oxide dispersion strengthened Ni-base alloy, MA 758, was studied at temperaturesranged from room to 950°C. The microstructure wasshown to have a pronounced effect on the fatiguestrength, which did not obey a simple correlationwith the tensile strength. The optimummicrostructure to extract the capability of thematerial was found and discussed from theviewpoint of the fatigue crack initiation andpropagation behavior depending on temperature. Anunique role of oxdation film, to which it wasworthy to pay special attention, was alsoidentified in the crack initiation at high temperature.