The precipitation of Al3(Sc,Zr) primary phase in aluminum alloys fabricated with Selective Laser Melting (SLM) can be influenced by various factors, including the alloy composition, processing parameters, and post-processing treatments. The Al3(Sc,Zr) phase is often desirable for its grain refinement (primary phase) and precipitation strengthening (secondary phase) effects. Primary Al3(Sc,Zr) in the melt act as potent nucleation sites for aluminium grains with warious morphology characteristics wich is dependent of cooling rate. However, the Al3(Sc,Zr) particles at the grain boundaries have similar sub-structures also.  The secondary Al3(Sc,Zr) is an ordered intermetallic compound that can provide precipitation hardening and contribute to the improvement of mechanical properties in the alloy. The size, distribution, and density of these precipitates significantly impact the alloy's final mechanical properties. Understanding the characteristics of secondary Al3(Sc,Zr) precipitates is crucial for optimizing heat treatment processes and designing aluminum alloys with enhanced mechanical performance for various applications. This study investigates the microstructure of an Al-Mg-Sc-Zr-Mn alloy using SEM and STEM. The general microstructure consists of an equiaxial ultrafine-grained (FG) band at the melt pool boundary and a relatively columnar and coarse-grain (CG) region at the melt pool core. Primary precipitation is evident in the grains and grain boundaries with other phases according to alloying elements (Mg, Mn) and impurities (Fe). The secondary spherical Al3(Sc,Zr) with the L12 phase, after heat treatment, can be observed and identified.