The Difference in the Grain Refining Capacity of Al-Ti Grain Refiners With and Without TiC

As a result of experimental investigations of cast samples prepared under various thermal conditions, TiC particles were shown to be effective in refining Al grains, particularly when a high content of Ti is dissolved in the Al melt. TiC particles are fairly stable in Al melt but decompose gradually during isothermal holding, the rate of decomposition being temperature dependent. TiAl3 particles can act as the nucleation center for Al when they exist in the liquid but the rate of dissolution of these particles is much faster than the rate of decomposition of TiC. The refinement due to the crystal-multiplication can be promoted by the existence of Ti in solution in certain freezing conditions. 12 ref.--JLMA.