Abstract
SiC particles are effective grain refiners in Mg-Al alloys. The greatest reduction in grain size
occurs in alloys with low Al contents, and therefore the investigation has been undertaken
with a commercial HP AZ31 Mg alloy. The presence of Mg2Si phases in the microstructure
and consideration of phase equilibria suggest that SiC can transform into Al4C3. If this happens
Al4C3 can also act as an effective grain refiner for Mg-Al alloys. The lattice misfit between
SiC, Al4C3 and Mg is in the same range, about 4%. Good grain refining achieved in
laboratory scale trials has been reproduced on an industrial scale vertical direct chill casting
machine. The influence of the casting speed and the addition of SiC as grain refiner on the
grain size across the cross-section of castings was investigated. A higher casting speed reduces
the grain size at the edge of the casting of non-grain-refined billets, but the grain size is
not consistent across the billet diameter. This variation in the grain size is not acceptable. After
the addition of SiC grain refiner, the grain size was homogeneous across the casting crosssection.
Originalsprache | Deutsch |
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Seitenumfang | 1 |
Fachzeitschrift | Berg- und Hüttenmännische Monatshefte |
Issue | 1 |
Publikationsstatus | Veröffentlicht - 2009 |
Research Field
- Ehemaliges Research Field - Low Emission Transport