Al-Ti-B grain refiners via powder metallurgy processing of Al/K2TiF6/KBF4 powder blends

The response to thermal exposure of ball-milled Al/K2TiF6/KBF4 powder blends was investigated to explore the potential of PM processing for the manufacture of Al-Ti-B alloys. K2TiF6 starts to be reduced by aluminium as early as 220 degrees C when ball-milled Al/K2TiF6/KBF4 powder blends are heated. The reaction of KBF4 with aluminium follows soon after. The Ti and B thus produced are both solutionized in aluminium before precipitating out as Al3Ti and TiB2. All these reactions take place below the melting point of aluminium. The ball-milled Al/K2TiF6/KBF4 powder blends heat treated at approximately 525 degrees C can be compacted to produce Al-Ti-B pellets with in situ formed Al3Ti and TiB2 particles. These pellets are shown to be adequate grain refiners for aluminium alloys. (C) 2009 Elsevier B.V. All rights reserved.