Formation of intermetallic phases in unrefined and refined AA6082 Al alloys investigated by using SEM-based ultramicrotomy tomography

•Microstructure of AA6082 Al alloys was studied using SEM serial ultramicrotomy tomography.•The formation sequence of intermetallic phases is related to the coarsening of α-Al dendrites.•TiB2 particles act as nuclei for the formation of β, α intermetallics and Mg2Si.•The grain refinement processing causes the severe interconnectivity of α-intermetallics.•Melt shearing is better to uniformly distribute and refine intermetallics than grain refiner.