Microstructures and mechanical behaviors of reinforced aluminum matrix composites with modified nano-sized TiB2/SiC fabricated by selective laser melting

TiB2/SiC/AlSi10Mg composite powders were prepared by adding nano-sized TiB2/SiC particles modified by γ-methacryloxypropyltrimethoxysilane (KH-570), and TiB2/SiC/AlSi10Mg composites were fabricated by selective laser melting (SLM) technology. The microstructures and mechanical behaviors of modified nano-sized TiB2/SiC reinforced AlSi10Mg alloys were explored. The results showed that KH-570 was stably adsorbed on the surface of modified powders, making mechanically mixed TiB2/SiC/AlSi10Mg composite powders distribution more uniform. Compared with the unmodified materials, the relative density of the modified nano-sized TiB2/SiC particle reinforced AlSi10Mg alloy was higher, reaching 98.7%. The average grain size of AlSi10Mg alloy was reduced from 8.9 μm to 2.7 μm by utilizing modified reinforced particles, and the tensile strength and elongation increased by 11.4% and 41.0%, respectively, which were better than the enhancement effect of unmodified materials. This work reveals that modified nano-sized TiB2/SiC helped to alleviate the load of the Marangoni convection effect during the SLM process, and significantly improved both strength and plasticity of composites.