Al–Si–Cu alloys were cast with the unique gradient solidification technique to producealloys with two cooling rates corresponding to secondary dendrite arm spacing (SDAS) of ∼9 and ∼27 μm covering the microstructural fineness of common die cast components.The microstructure was studied with optical microscopy and scanning electronmicroscopy (SEM) equipped with energy dispersive spectroscopy (EDS) and electronbackscattered diffraction (EBSD). The alloy with higher cooling rate, lower SDAS, hasa more homogeneous microstructure with well distributed network of eutectic and intermetallicphases. The results indicate the presence of Al–Fe–Si phases, Al–Cu phases andeutectic Si particles but their type, distribution and amount varies in the two alloys withdifferent SDAS. EBSD analysis was also performed to study the crystallographic orientationrelationships in the microstructure. One of the major highlights of this study is theunderstanding of the eutectic formation mechanism achieved by studying the orientationrelationships of the aluminum in the eutectic to the surrounding primary aluminumdendrites.