70 Prakt. Met. Sonderband 38 (2006)
Fig.4: Light optical micro-
graph of remelted and
gravity cast AG5.7S51.9
showing primary o-den-
drites (coarser than in
Fig.2) and regular “Chinese
script” Mg»2Si structures
(black) with about 10 um
distance in between.
{UL ym
UJ Jn
TEE - _
Fig.5: LOM of remelted and gravity cast AG5.7S2.4 showing in a) coarser a. dendrites and
Mg2Si structures than in Fig.3a; the marked area is enlarged in b) demonstrating the
different size classes of the interdendritic structures (submicron to 20um)
FE
hete
a
whic
Fig.6: LOM of gravity cast AG5.8S5.6 showing in a) a. dendrites and a higher volume not s
fraction of Mg,Si structures than in Fig.3; b) shows a star-like Mg,Si structure, Fe-rich view
“needles” (marked Fe) and fine structured eutectic areas (marked eut). preci
level
The highly alloyed, gravity cast AG4.9S8.4 sample is depicted in Fig.7a after solution treat Cros:
ment. The chinese script Mg,Si became rounded, and the fine eutectic spheroidized. Fig. wher
7b-f show images of the same region depicting all 3 phases: Mg2Si, eutectic Si and AlFeSi. appe