Characterization of precipitates in a Fe-10Cr-6Mo-0.5Nb ferritic steel

In the course of studying radiation damage in ferritic steels, there was a need for information on the nature of precipitate phases in one of the steels, an alloy of composition Fe-10Cr-6Mo-0.54Nb-0.33V-0.45Mn-0.3Si-0.05C (wt%). Since suitable data were not available in the literature an analysis was performed. The experiments were done with 3-mm diam disks punched from 0.5-mm thick rolled strips. The disks were annealed in evacuated quartz capsules for 1h at 11500C, followed by cooling to room temperature in an unheated part of the furnace, then reheated to 7300 for 1h and cooled again in the cold zone. The microstructure consisted of equiaxed ferrite grains containing several apparently different precipitates. A morphological distinction between the various precipitates was made by optical metallography and transmission electron microscopy (TEM). The precipitates were analyzed in the TEM foils and in extracted form on carbon films by electron diffraction and energy dispersive x-ray spectroscopy (EDS), and in extracted form on single-crystal silicon substrates using conventional x-ray diffraction. 9 references 3 figures