Fig. 8. STEM EDS linescan through the particle present in the grain
interior. Mainly W is rich within the particle, while content of Fe, Ni
and Cu is significantly depleted or absent.
Fig. 9 shows the STEM image of the foil and the EDS map illustrating the
composition of particles developed at the grain boundaries and in its
neighbourhood. EDS analysis indicates the formation of Cr-rich particles
decorating the grain boundary. The area close to the grain boundary is
rich in Cr and is heavily depleted in Fe and Ni. In steels having the
essential content of Cr, there is a strong tendency to the rapid
formation of numerous Cr-rich particles of
M23C6 type 29.
M23C6 particles nucleate rapidly
preferentially at high angle grain boundaries which is in accord with
the results of Mazánová et al. 14. Fig. 9 also shows
the chains of Cu-rich particles and small-scale Nb-rich particles
nucleated at the grain boundary. Cu-rich particles nucleated at the
grain boundary are substantially larger than those in the matrix.