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/mm(3). 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 (similar to 536.9 MPa and similar to 16.5 %) and vertical (similar to 517.3 MPa and similar to 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.

Automated summary

The study demonstrates that the 6.5 wt% TiB2/AlSi10Mg composite manufactured by SLM has a wide processing window and excellent tensile properties. The material exhibits uniform equiaxed microstructures, and its tensile properties surpass those of reported SLM-ed matrix alloys and other particle reinforced Al-Si composites.