Abstract: The interactions between high temperatures creep and low cycle fatigue in an Fe-25Ni-15Cr based alloy GH132 has been studied under three different loading schedules: (a) continuous cyclic creep, (b) prior creep followed by fatigue, and (c) prior fatigue followed by creep. It is found that the interaction appears nearly linear for all the three schedules. The behavior of interaction in GH132 alloy is different from that previously observed in a GH30 alloy (Nimonic 75 type), in which although the interaction at schedules (a) and (c) was linear, a pronounced negative interaction occurred at the schedule (b), i.e., prior creep followed by fatigue. This difference is found to be associated with the difference in the evolution of microstructure. In the GH132 alloy, no cell structure is formed during the tests, while in the GH30 alloy, cell structure is well developed during prior creep, which impedes the motion of dislocations during sequential fatigue, resulting in a negative interaction between creep and fatigue.

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