Fachbereich 11 - Physik
Institut für Materialphysik
Strengthening and Nanostructure of Metals and Alloys

The effect of precipitate free zones on the yield strength of polycrystals of the
commercial g'-strengthened nickel-base superalloy NIMONIC PE16

The g'-precipitate dispersion and the width w of g'-precipitate free zones (PFZ) along grain boundaries have been varied systematically. The yield strength s_y was found to decrease as w increases provided w exceeds some minimum value. The maximum observed decrease of s_y amounts to 30 %. The dislocation processes in the PFZs have been studied by stretching thin foils inside a transmission electron microscope and observing the glide of dislocations under full load. Softening due to PFZs is mainly caused by the ease with which dislocations are created in the PFZs; this leads to concentrated slip.

Drittmittelgeber:

Deutsche Forschungsgemeinschaft

Beteiligte Wissenschaftler:

Dr. D. Baither, Dipl.-Phys. T. Herding, Dipl.-Phys. T. Krol, Prof. a. D. Dr. E. Nembach (Leiter)

Veröffentlichungen:

Krol, T., D. Baither, E. Nembach: Quantification of the detrimental effects of precipitate free zones on the yield strength of a superalloy, Scripta Mater., 48, 1189, 2003

Baither, D., T. Herding, T. Krol, R. Reichelt, E. Nembach: The effects of precipitation free zones on order strengthening in NIMONIC PE16 bi-crystals, Mat. Sci. Eng., A319-321, 279, 2001