Evolutions of grain size and nucleating particles in carbon-inoculated Mg–3% Al alloy

Abstract

The grain refinement of primary α-Mg phase in the Mg–3% Al alloy was studied by carbon inoculation. The grain size and nucleating particles in the samples cast from the melt held at different times after inoculation were observed. It is found that the primary α-Mg grains in the Mg–3% Al alloy could be effectively refined from the melt immediately inoculated. The grain size maintained relatively stable with increasing holding time from 5 to 120min. Therefore, no obvious fading effect could be observed in the Mg–3% Al alloy inoculated by carbon. However, the holding time had no obvious effect on the particle densities, particle size distribution and the mean size of Al–C rich particles in the samples held over 5min after inoculation. The particles varied in a range of 2–4.5μm with a mean size of 2.85μm. The number of active nucleating particles with the size larger than 3μm was stable at prolonged holding time over 5min, which resulted in the less fading in the inoculated melt.