Ti transition zone on the interface between TiC and aluminum melt and its influence on melt viscosity

EPMA and TEM analysis shows that there is a Ti transition layer around TiC particles in the α-Al grain center both in the usually solidified sample and in the rapidly solidified ribbon. Because the rapid solidification restrains the solute of the melt to diffuse before solidification, the rapidly solidified ribbon can conserve the instantaneous structure of the melt mostly, indicating that the Ti transition layer originates from the Ti transition zone in the melt. A new theory named as “Ti transition zone” theory has been proposed as a possible refinement mechanism for pure aluminum by Al–Ti–C refiner, and its formation model is given. The influence of the Ti transition zone on the melt viscosity was also discussed in this paper.