Microstructure Evolution and Reinforcing Mechanisms of the Slmed Aln/Alsimg Composites Fabricated Under Different Laser Energy Density

Abstract

Microstructure is very sensitive to the printing parameters in additive manufacturing and high performance materials could be designed by suitable printing parameters. In this work, influences of laser energy density on the microstrucutre and tensile properties of SLMed AlN/AlSiMg composites were investigated. Firstly, influences of laser energy density on the density and defects evolution of the SLMed AlN/AlSiMg composites were studied. Especially, when the laser energy density was fixed, discrepancies of scanning speed and hatch spacing on the micrsostrucure of the SLMed AlN/AlSiMg composites were also discussed. Secondly, the in situ fabrication of AlN during the SLM process under the laser energy density of 83.3 J/mm3 to 180.6J/mm3 was depicted. Meanwhile, the influences of AlN on the microstructure of eutectic Si network were illustrated. Finally, the strengthening effects and fracture behavior of the SLMed AlN/AlSiMg composites were revealed based on the tensile properties and fracture surface observation. Our finding in this work may provide a feasible experimental reference and theoretical basis for SLMed light weight composites.

Keywords: SLM, Al composites, AlN, laser energy density, strengthening mechanism