<p>The paper investigates the effects of selective laser melting (SLM) processing parameters on the formability, microstructure, and mechanical properties of Al-Cu-Mg alloys with simultaneous additions of Sc and Zr. It systematically explores the relationship between laser volumetric energy density (VED) and macro-defects, as well as the mechanisms underlying their formation. The microstructure of the alloy is composed of equiaxed grains and columnar grains. An increase in energy density leads to the transformation of columnar grains into equiaxed grains. The alloy exhibits only a large number of primary <i>θ</i> (Al₂Cu) phase, which appears as continuous agglomerates. Additionally, an ellipsoidal <i>w</i> (AlCuSc) phase is observed within the <i>θ</i> (Al₂Cu) phase. The contributions of different strengthening mechanisms to the yield strength of the alloy are obtained through theoretical calculations.</p>