Abstract
Al-Ti-B alloys are the most commonly used grain-refiners in the casting of aluminum alloys; however, the grain-refining mechanisms are still not conclusive. Quantities of the two kinds of phase particles, TiB 2 and Al 3 Ti, introduced into the molten aluminum by the addition of Al-Ti-B grain refiners are determined experimentally. It is found that the quantities of Al 3 Ti particles introduced are much lower than those of grains in the as-cast aluminum alloys, while those of introduced TiB 2 are higher. Thus it is concluded the Al 3 Ti particles in the A1-Ti-B grain-refiners cannot be the primary nucleation sites during solidification of aluminum. © 2002 Elsevier Science B.V. All rights reserved.