The research study explored the impact of magnesium on the microstructural characteristics and mechanical properties of Al-Mg-Mn alloy in both its as-cast and homogenized states. Various analytical techniques including optical microscopy, x-ray diffraction, scanning electron microscopy, energy-dispersive x-ray spectroscopy, Vickers microhardness testing, and electrical conductivity measurements were employed for the analysis of the Al-Mg-Mn alloy. The findings reveal that the primary phases present in the as-cast alloy consist of α-Al, β ( \({\text{Al}}_{3}{\text{Mg}}_{2}\) ), and \({\text{Al}}_{6}\left(\text{Mn},\text{ Fe}\right)\) . As the magnesium content increases, notable alterations are observed in the diffraction angle θ, inter-planar spacing d, lattice constant a, and the solute magnesium concentration in the α-Al matrix. In instances where the Mg content is low, the grain size and distribution in both the as-cast and homogenized alloys appear coarse and uneven. However, as the magnesium content rises, there is a reduction in the primary dendrite length and columnar crystal zone in the as-cast alloy, alongside enhanced development of secondary dendrites and gradual diminishment of the grain size. This reduction in grain size is particularly pronounced in the homogenized alloy. Additionally, the hardness of both the as-cast and homogenized alloys experiences an increase, while the electrical conductivity undergoes a decrease with escalating magnesium content. Notably, in comparison with the as-cast alloy, the hardness and electrical conductivity of the homogenized alloy exhibit enhancements. The outcomes of this study offer valuable insights for the subsequent processing and deformation applications of the Al-Mg-Mn alloy.
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