Application of electron energy loss spectroscopy to microchemical analysis of Ti-modified austenitic stainless steel irradiated in HFIR

Abstract

Microchemical analysis on Ti-modified austenitic stainless steel specimens, irradiated to 56 dpa at 773 K in the High Flux Isotope Reactor (HFIR) was conducted by utilizing electron energy loss spectroscopy (EELS). EELS results of precipitates extending through the foil surface were compared with the typical results by energy dispersive X-ray spectroscopy (EDS) on the precipitates, which were extracted on carbon replica films. Reasonably good agreement was obtained between the results by EELS and those by EDS. Comparing the EELS spectrum from a precipitate and the adjacent matrix, spatial resolution was obtained to be about 20 nm or better. EELS results on dislocation loops with sizes of about 20 nm in diameter and oriented normal to the foil surface revealed that the enrichment of Ti and Cr had occurred by irradiation. The pressure of helium gas atoms in a cavity of about 10 nm in diameter was estimated from the EELS spectra. The energy shift of the plasmon loss peak indicated that the pressure was of the order of 10 8 Pa.