Process Optimization, Microstructure Characterization, and Mechanical Properties of Al-Mg-Sc-Zr alloys Prepared via Laser Powder Bed Fusion

Aluminum alloys manufactured using traditional processes are increasingly unable to meet the high flexibility and performance requirements of modern engineering. In this study, Al-Mg-Sc-Zr alloys were manufactured via laser powder bed fusion (LPBF) to obtain high-performance aluminum alloys. To this end, process parameter optimization and heat treatment were adopted. The optimal process parameters were determined by initially analyzing the relative density and defect distribution under varying energy densities. The sample obtained under the optimal process parameters exhibited a relative density of 99.84%. Subsequently, the corresponding phase compositions, microstructures, and mechanical performance of the as-fabricated specimens were determined using the optimal process parameters before and after heat treatment. The microstructures of the samples showed typical equiaxed columnar bimodal grain structures, with A l 3 ( Sc , Zr ) precipitates detected. The samples exhibited no significant anisotropy before and after heat treatment, while the grain orientation differences were dominated by high-angle grain boundaries. The mechanical properties of all the samples were characterized using tensile and hardness tests. The yield strength, ultimate tensile strength, and elongation of the sample were 475.0 MPa, 508.2 MPa, and 8.3%, respectively. Overall, samples with high density, low porosity, high strength, and high plasticity were obtained by process parameter optimization and appropriate heat treatment.