EELS and EDS fracture mode analysis at grain boundaries of Cr-Mo steel

Abstract

Electron energy loss spectroscopy (EELS) and energy dispersion spectroscopy (EDS) were used to study the chemical composition and bonding of grain boundary in CrMo steel. The bonding change in grain boundary of commercial CrMo steel is induced by P element segregation. The normalized 3d occupancies of states of irons both in bulk and at grain boundary were calculated according to the EELS spectra and they were related to the change in the chemical compositions of grain boundaries and the fracture mode. If the grain boundary has a higher occupancy of 3d state of iron than the bulk, the sample tends to have intergranular fracture, while if the grain boundary has almost the same occupancy of 3d state of iron as the bulk, the sample tends to have transgranular fracture.