Fatigue-induced precipitates at grain boundary of Nb-A286 alloy in high temperature low cycle fatigue

A quantitative analysis of the effect of the total strain range on the η precipitates at grain boundary under high temperature low-cycle fatigue has been interpreted for Nb-A286 alloy. The value of the activation energy of η phase formation with total strain range was analyzed by using the in situ X-ray diffraction (XRD) technique and the differential thermal analysis (DTA) technique. The applied strain during the low-cycle fatigue decreases the activation energy of η phase formation at grain boundary. The trend of decreasing the temperature of η phase formation with the applied strain was found to be due to the accommodation of deformation near grain boundary.