Materials Science Forum, Vol.396-4, 45-51, 2002
Studies on the sedimentation and agglomeration behavior of Al-Ti-B and Al-Ti-C grain refiners
The sedimentation and agglomeration behavior of Al-Ti-B and Al-Ti-C grain refiners in liquid aluminum has been investigated using the LiMCA and PoDFA analysis techniques in combination with metallographic examination. The widely used Al-5%Ti-1%B and Al-3%Ti-0.15%C master alloys were chosen. Two aluminum alloys, an AAlxxx (commercially pure metal) and an AA5182 (Al-4.5%Mg) alloy, were prepared with different additions of grain refiners. The difference in particle behavior in liquid aluminum for both refiners is described and briefly analyzed in terms of sensitivity to agglomeration and grain refiner performance. Experimental results indicate that, in comparison with the Al-Ti-B refiner, the AI-Ti-C refiner is detrimentally affected by long holding periods due to the decomposition of TiC particles within the melt.
Keywords:aluminum alloys;grain refinement;Al-Ti-B grain refiner;Al-Ti-C grain refiner;sedimentation;agglomeration;TiC instability