72  Prakt. Met. Sonderband 38 (2006) 
volume view in Fig.9. The represented volume of about (200 um)® contains more than 10 5.D 
Mg.Si “corals”, which are interpenetrating and can hardly be separated from each other. 
Fig.9b shows a grey level histogram, in which the regions for separating the phases are The 
marked. Summing all the voxels (>27) within the different grey value regions provides the start 
volume fraction of the phases. That of Mg,Si is slightly bigger than predicted by [6]: rems 
AlMg5.8Si5.6: 0.9 — 1.8 vol.% AlFeSi, 9.1 — 11.3 vol.% (9 vol.% [6]) Mg2Si; stoe 
AlMg4.9Si8.4: 1.1 — 2.0 vol.% AlFeSi, 8.8 — 10.8 vol.% (8 vol.% [6]) Mg2Si. dary 
594° 
rest 
temg 
relat 
gate 
until 
sepa 
up tc 
wt% 
Si ar 
dify | 
gethe 
558° 
Simil 
577° 
rema 
AGS 
' form: 
— Fig.1 
Fig.8: Details of 3D micro-tomogram of an AG4.9S8.4 sample recorded with a voxel size of the € 
(0.7 um)>. a) Connected AlFeSi phase discriminated by grey value selection (see Fig.9b); triple 
b) a slice of the tomogram showing Mg.Si dark and AlFeSi white (similar to BSE in Fig.7d). analy 
not c 
ntensitı dend 
gravi 
3.0E+05 
2.0E+05 AlFeS 
1.0E+0! 
Gray level 
U 20 39 58 77 96 115134 153 172 191 210 229 248 
Fig.9: a) 3D Mg,Si structure in a 
cube of about 200 ym edge length 
extracted from a (0.7um)® voxel- 
tomogram of an AG4.9S8.4 
sample; 
b) shows a grey value histogram 
indicating the regions for the 
separation of the different phases.