12%Cr鋼の焼戻しによる炭化物析出について

抄録

Precipitation characteristics of 12%Cr steel during isothermal tempering were studied mainly by a transmission electron microscope. As the result, the shape, nucleation site and habit plane of each carbide (Fe₃C, (Cr, Fe)₇C₃, (Cr, Fe)₂₃C₆), and the orientation relationships between carbides and ferrite matrix were clarified. It was confirmed that the transformation from Fe₃C to (Cr, Fe)₇C₃ occurs by both in situ and separate nucleation and the transformation from (Cr, Fe)₇C₃ to (Cr, Fe)₂₃C₆ by separate nucleation at grain boundaries. Furthermore, it was concluded that the secondary hardening may be induced by the distribution of fine granular particles of (Cr, Fe)₇C₃ nucleated separately on the dislocations in the region of high dislocation density.