Abstract
The mechanism of grain refinement was investigated for Mg–Al alloys inoculated with SiC particles. Contrary to the previously
reported Al4C3 hypothesis, the ternary carbide Al2MgC2 was observed, which has a crystal structure closer to that of Mg than to
that of Al4C3. In the centre of the grains, one or more “hillocks” enriched in Al and C were observed. Based on the observed phenomena,
a novel mechanism is suggested to explain the grain refinement of Mg–Al alloys with the addition of SiC particles.