EFEITOS DA ADIÇÃO DO INOCULANTE Al-3%Ti-1%B ÀS LIGAS DO SISTEMA Al-Si

Abstract

Grain refinement of the as-cast macrostructure by the addition of the inoculant Al-3%Ti-1%B is examined for Al-3%Si, Al-7%Si, and Al-11%Si alloys using thermal and Fourier analyses as well as quantitative metalography. The effects of inoculant addition on the cooling curves, on the grain size, on the solid fraction evolution with time, and on the latent heat of transformation are investigated. The results show that the cooling curves are changed significantly with the inoculant addition only at the beginning of primary solidification. The evolution of solid fraction with time, however, occurs more slowly with the addition of inoculant. For the Al-3%Si alloy, the time rate of solid formation decreases from the beginning of solidification to a solid fraction of 50%. The average grain size decreases substantially with the addition of the inoculant, suggesting the presence of a larger number of grains during solidification