| Popis: |
The master alloys based on the Al-Ti-b system have been used extensively for grain refining aluminum alloys. The TiB2 particles in commercial AlTiB master alloys, however, are rather coarse and have a tendency to agglomerate both during the manufacturing process and after being released into the melt, leading to a number of quality problems. These quality-related problems have created a big demand for an acceptable replacement for AlTiB master alloys. The Al-Ti-C system thus received particular attention as TiC has been assumed for a long time to be the nucleant for aluminum treated with hypo-peritectic Ti concentrations. TiC particles are claimed to be smaller than the TiB2 particles and are less prone to agglomeration. The Al-3%Ti-0.15%C alloy of this new generation grain refiners have been used commercially for several years in a wide range of alloy systems. Much of the work reported on this alloy, however, has been from laboratory scale testing while data on commercial applications is rather scarce. In the present work, coomercially available Al-3%Ti-0.15%C grain refiner was employed in the twin roll strip casting of the AA8111 alloy. Its grain refining potency was compared with that of the Al-5%Ti-0.2%B master alloy, the standard grain refiner in aluminium industry for the manufacture of aluminium fin and foil products. |
