Abstract
A centrifuge which can apply centrifugal forces up to 1.4∼1.9×104 m/s to aluminum melt has been fabricated.
Al-0.14%Ti melts containing TiC particles were subjected to various centrifugal fields at 900°C and it was found that the aluminum grain counted after solidification in the stationary state was coarser with an increase of the centrifugal force applied to the melts.
As titanium in solution is not changed by the centrifugal treatments, the grain coarsening of aluminum appears to take place by the sedimentation of some solid nucleating particles in the melts.
The sedimented TiC particles were observed at the bottom of the samples after the centrifugal treatments.
The ratios of TiC particle number remaining in the melts to the initial one were calculated on the basis of the TiC size distribution measured in the refiner and it is shown that this result is consistent with the tendency of the grain coarsening.
It is concluded therefore that the TiC particles dispersed in aluminum melt act as the nucleating agents to cause the refinement of aluminum solidified grains.
