Es erkennt hier eine sprudelnde Quelle. Wir auch. - ULV Leoben ...
Es erkennt hier eine sprudelnde Quelle. Wir auch. - ULV Leoben ...
Es erkennt hier eine sprudelnde Quelle. Wir auch. - ULV Leoben ...
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158<br />
A study of the modification of<br />
Al-Si & Al-Mg 2 Si eutectic<br />
An investigative study of heterogeneous nucleation using an entrained droplet<br />
technique in an Al-Si alloy & the solidification microstructure and morphology of<br />
Mg 2 Si in an Al-Mg-Si alloy by using a Bridgman furnace.<br />
Al-13.1%Mg 2 Si near eutectic alloys were prepared<br />
in a Dietz mould using high purity Al, Si & Mg. Additions<br />
of Sr & Y in the form of master alloys were<br />
made to modifiy the morphology of Mg 2 Si. With the<br />
addition of Sr the Mg 2 Si morphology appears to be<br />
flake or block-like while with the addition of Y the<br />
morphology changes to fine fibres as can be seen<br />
from the deep etched samples (see Fig. 2). Planned<br />
future work includes the use of a Bridgman furnace<br />
to see the effect on the solidification microstructure<br />
and eutectic morphology using different growth<br />
velocities and temperature gradients. Al-Al 3 Ni regular<br />
eutectic will be use to confirm the steady state<br />
growth (see Fig. 2).<br />
Muhammad Zafar<br />
Lehrstuhl für Gießereikunde<br />
an der MUL seit: 2007<br />
Email: muhammad-zafar.zarif@stud.unileoben.ac.at<br />
institute.unileoben.ac.at/giessereikunde<br />
Zur Person:<br />
M.Sc Eng. from PIEAS, Pakistan<br />
derzeit: Ph.D. Student at Chair of Casting Research (MUL)<br />
A high purity Al-Si master alloy was prepared by arc<br />
melting under high vacuum to reduce contamination.<br />
The alloy was then melt-spun on a rotating Cu wheel<br />
to produce a ribbon 3 mm wide and 85 µm thick. The<br />
DSC traces obtained from the ribbons showed two<br />
exothermic peaks. The first peak corresponds to the<br />
solidification of grain boundary eutectic, while the<br />
second peak corresponds to solidification of eutectic<br />
droplets in the Al matrix (see Fig. 1). A brightfield<br />
TEM image of an entrained droplet (see Fig. 1).<br />
Forschungspartner:<br />
Forschungsschwerpunkte:<br />
Solidification, especially modification of Al-Si and<br />
Al-Mg-Si alloys