Multi-scale mechanical properties of Al–Mg–Zr–Sc alloys fabricated by direct metal laser sintering: Towards single-material composites

This study proposes a methodology for experimentally deriving parameter-dependent mechanical properties of DMLS-printed aluminum. Eighty-five specimens were produced using seventeen distinct parameter sets, designed through a Design of Experiments approach, and subjected to non-destructive and destructive testing. The results reveal a strong correlation between printing parameters, porosity, and mechanical performance, with average pore areas ranging from 0.037% to 21.161% and varied pore types (spherical pores, keyhole pores, and lack of fusion). Correspondingly, mechanical properties showed a broad range: tensile strength (105.3 MPa–459.0 MPa), Young's modulus (23.38 GPa–69.77 GPa), and yield strength (105.2 MPa–444.8 MPa). Single-material composites were fabricated by integrating dense and porous structures within a single geometry. Tensile testing of these composites showed that geometry and the cross-sectional ratio of ductile material influence mechanical properties significantly (tensile strengths ranging from 89.8 MPa to 112.2 MPa), with stress-strain responses displaying atypical behavior due to the brittle, porous matrix and embedded ductile truss-lattice structures.