Etude par Sonde Atomique Tomographique de la formation de nano ...

tel-00751814, version 1 - 14 Nov 2012
Chapter 4. Nitride Dispersion Strengthened Steels
Figure 4.37. Composition of particles (denoted as (2)) observed in nitrided NDS steel
annealed at 700°C during 1h. Only Cr, N, O, Al and Fe (at.%) is shown.
A composition profile plotted through the largest nanoparticle (as indicated by black
dashed arrow Figure 4.35) is shown in Figure 4.38. From this profile, it can be seen that this
particle is enriched in Cr and N and almost depleted in Fe. The content of Fe reaches 2.0
at.%.
Concentration of Cr, N and Fe (at,%)
100
90
80
70
60
50
40
30
20
10
0
0 5 10 15 20 25 30 35 40 45 50 55
Distance (nm)
Figure 4.38. Composition profile for Cr-N-rich particle observed in nitrided NDS
steel annealed at 700°C/1h. Profile drawn for large particle (which is clearly seen in the end
of 3DAP analyse) in direction of analyse as indicated in Figure 4.35-(2). Sampling volume is
5×5×1 nm 3 . Only Cr, N and Fe (at.%) are shown.
An estimation of the particle number density for this state is rather complicated, since
particles are close to each other, partially interwoven and cross the analyzed volume.
Cr
N
Fe
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