Analysis of the response to thermal exposure of Al/K2TiF6 powder blends

The response to thermal exposure of mixed and ball-milled Al/K2TiF6 powder blends was investigated in an effort to explore the potential of powder metallurgy processing in the production of Al-Ti alloys. K2TiF6 reacts with aluminium in the solid state, producing Al3Ti and the inorganic salts, KAlF4 and K3AlF6. This reaction which occurs shortly before the melting of aluminium when K2TiF6 and aluminium powders are merely mixed, starts as early as 220 degrees C when the two powder components are ball-milled before thermal exposure. Heating ball-milled Al/K2TiF6 powder blends in an inert atmosphere for 1/2 h at approximately 500 degrees C suffices to produce a very fine dispersion of Al3Ti particles inside aluminium grains. The alloy powder thus obtained can be compacted to manufacture Al-Ti pellets which can be employed for grain refining aluminium alloys. (C) 2008 Elsevier B.V. All rights reserved.