Macrostructural and Microstructural Study in Alloys Hipoeutecticas AL-SI Solidified Directionally

Abstract

In this work, unidirectional solidification experiments were carried out in a Bridgman type furnace with Al-4wt. %Si and Al-6wt. %Si alloys, using different cooling rates, V_e. The cooling curve was used to determine the values of cooling rates, V_e and dendritic growth rates, V_c, and temperature gradients, G_t. It was observed that columnar grain size (length and width) and secondary dendritic spacing (λ₂) decreased with increasing V_e. Also, the presence of a columnar-to-equiaxed transition zone, CET, was observed. Likewise, the values of the microhardness Vickers, HV, were measured, determining that the values of HV increased as it does the V_e and the content of Si, due to the increase of the phase β and the refinement of the lamellae of the eutectic.