Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Al-Ni hypoeutectic alloys were directionally solidified under upward transient heat flow conditions. The aim of the present study is to set up correlations between the as-cast microstructure and the resulting mechanical properties of these alloys. The dependence of primary and secondary dendrite arm spacing on the alloy solute content and on solidification thermal parameters is also analyzed. The results include transient metal/mold heat transfer coefficient, tip growth rate, cooling rate, dendrite arm spacing, ultimate tensile strength, yield tensile strength and elongation. Expressions relating dendrite spacing to solidification thermal parameters and mechanical properties to the scale of the dendritic microstructure have been determined. It was found that the ultimate tensile strength and the yield tensile strength increase with increasing alloy solute content and with decreasing primary and secondary dendrite arm spacing. In contrast, the elongation was found to be independent of both alloy composition and dendritic arrangement.1613949Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAEPEX -UNICAMPFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)