Printability enhancement and mechanical property improvement via in situ synthesis of carbon nanotubes on aluminium powder

Abstract

A strategy of powder surface functional modification involving in situ synthesis of carbon nanotubes (CNTs) on Al powder is described to address the poor forming ability and inferior mechanical properties of Al parts produced by laser powder bed fusion. The obtained CNTs-Al composite powder exhibited a combination of high sphericity and flowability of powder, as well as good dispersion uniformity, bonding force and structural integrity of CNTs. The presence of CNTs significantly reduced the laser reflectivity and enhanced the printability of Al powder. The in situ synthesized CNTs contributed to reinforcement after printing and enhanced the tensile properties of printed sample. The printing behavior of powder, the distribution of reinforcement, and the tensile properties of printed sample were optimized by tuning the content of CNTs. The CNT-content in the composite powder was optimized at 0.96 wt% to achieve the synergy of high forming quality, densification and good tensile properties. • High-quality carbon nanotubes (CNTs) were in situ synthesized on Al powder. • Coating CNTs effectively increased the laser absorptivity of Al powder. • The incompatible issue of Al powder with laser additive manufacturing was addressed. • High forming quality and good properties of were obtained in the printed composite.