In this work a solidification experiment was carried out to investigate the effect of heat flow parameters, such as growth and cooling rates (VL and TR, respectively) on the evolution of the microstructure and hardness of the unsteady-state solidified Al-33%Cu-1%Bi alloy. The referred parameters were obtained experimentally by means of temperature monitoring using a set of thermocouples that were inserted inside the metal. The thermodynamic computational tool Thermo-Cal was used to generate the equilibrium phase diagram as well as the theoretical solidification path of investigated alloy, in turn, it was compared with the typical experimental microstructure obtained by optical and scanning electron microscopy/energy-dispersive spectroscopy. It was found that both VL and TR as well as the as-cast microstructure showed varying values during solidification. This allowed the proposal of experimental equations of eutectic spacings growth (E) as a function of the heat flow parameters represented by the following mathematical relations VL.E1/2 = Constant and TR.E ¼ = Constant. The typical solidification microstructure was formed by a coarser region composed of the primary phases Al2Cu+Alα, surrounded by another region of eutectic dendrite colonies with the mixture (Al2Cu+ Alα)eutectic plus Bi globules and Fe intermetallic. Finer eutectic microstructures acted as a resistance-increasing mechanism.
