Selective laser melting of TiB₂/AlSi10Mg composite: Processability, microstructure and fracture behavior

Recently aluminum matrix composites (AMCs) manufactured by selective laser melting (SLM) have attracted extensive attention in the lightweight application fields. In this work, pre-alloyed 6.5 wt.% TiB₂/AlSi10Mg composite powder was initially densified via SLM. The result indicated that the material had a wide processing window, and the fully dense bulked samples were successfully fabricated when the laser volumetric energy density is 50–70 J/mm³. We concluded that the morphology, size, and distribution of TiB₂ particles in the as-deposited condition were generally consistent with those of the powder. The fine equiaxed microstructures without apparent anisotropy were remarkably realized. Therefore, a superior combination of excellent tensile strength and elongation was evident in the horizontal (∼536.9 MPa and ∼16.5 %) and vertical (∼517.3 MPa and ∼15.4 %) directions due to the systematic processing optimization, accompany with the strong work hardening capability. Its tensile properties are higher than that of the reported SLM-ed matrix alloy and other particle-reinforced Al-Si composites. Besides, the fracture behaviors were complicated, and the crack propagation paths were affected not only by the defect and eutectic Al-Si of the molten pool boundary (MPB) but also by the homogeneously distributed TiB₂ particles. This study is expected to establish an important guiding significance for the practical engineering application of SLM-ed in-suit TiB₂/AlSi10Mg composite.