ABSTRACT
In order to investigate the influence of AlB2 and AlB12 particles on the grain refining performance of an Al-4B master alloy in aluminum-silicon casting alloys, Aluminum Association TP-1 grain size tests were performed for varying concentrations of AlB2 and AlB12. For the chemical characterization, optical emission spectrometry and energy dispersive spectrometry (EDS) were used. Grain sizes were measured by line intercept method using stereoscopic microscope. The results were compared with the conventional grain refiner Al-5Ti-1B. The aluminum-silicon alloy used was the Al-11Si-0.1Mg, common in the production of automotive wheels. The master alloy Al-4B with 100% of AlB2 particles showed the best refining performance, providing average grain sizes of 0.26 mm in the alloy Al-11Si-0.1Mg after sampling time of 5 minutes. The alloy Al-4B with 100% of AlB12 particles showed an intermediate result, with average sizes of 0.43 mm in the alloy Al-11Si-0.1Mg after sampling time of 5 minutes. The alloy Al-11Si-0,1Mg refined using the conventional grain refiner Al-5Ti-1B presented average grain size of 0,63 mm after 5 minutes of sampling time, the worst result compared with the refiners Al-4B with 100% of AlB2 and AlB12 particles respectively.
Keywords:
Grain refine; aluminum; boron.
