DEFORMATION MECHANISMS IN NI-BASE DISK SUPERALLOYS AT HIGHER TEMPERATURES

This paper presents results from a research initiative aimed at investigating high temperature creep deformation mechanisms in Ni-base superalloys through a combination of creep experiments, TEM deformation mechanism characterization, and state of the art modeling techniques. The effect of microstructure on dictating creep rate controlling deformation mechanisms was revealed for specimens with a bimodal �� size distribution that possessed different secondary �� size, tertiary �� volume fraction, and � channel width spacing. It was found that the less creep resistant microstructure was the one with a greater secondary �� size, wider � channel width, and higher volume fraction of tertiary �� . Deformation in this microstructure commences by way of

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