High temperature strength of ODS superalloys due to dispersoid-dislocation interaction

Abstract

The microstructure of the oxide-dispersion strengthened (ODS) superalloy Inconel MA 6000 was studied by TEM after creep and high-temperature low-cycle fatigue. The micrographs suggest that an attractive interaction between dislocations and dispersoid particles exists at high temperatures, which makes the detachment of the dislocations from the dispersoids the strength-determining process. These observations are shown to be compatible with a newly developed theory incorporating an attractive interaction in the treatment of particle bypass by dislocation climb. Preliminary comparison between theoretical predictions and experimentally measured "threshold stresses" for creep exhibits promising agreement.