Mechanical behavior and microstructure of 3D-printed carbon nanotubes-reinforced Cu composite

Abstract This paper addresses the current limitations of three-dimensional (3D)-printed materials by developing a novel ink formulation using carbon nanotubes (CNTs)-reinforced Cu matrix composites. The fabricated inks consisted of CNTs/Cu powders with a binder (polyethylene glycol/polyvinyl butyral) and a solvent mixture (anhydrous ethanol/triethyl phosphate). 3D CNTs/Cu composites were fabricated by a process that included molecular-level mixing (MLM), micro-extrusion-based 3D printing (MED-3D), and pressureless sintering. The 3D-printed CNTs/Cu composite was prepared via an MED-3D process and exhibited structural stability and dimensional accuracy. The porosity and mechanical strength of the 3D-printed CNTs/Cu composite were controlled by optimizing the sintering temperature. The 3D-printed CNTs/Cu composites (surface porosity: 6.01%; internal porosity: 4.45%; sintering temperature: 1173 K) exhibited outstanding mechanical strength, reaching a maximum compressive strength of 10.65 ± 0.9 MPa, which is 104.9% higher than that of pure Cu. It is expected that CNT-reinforced metal matrix composites with structural and functional integration can be prepared by introducing CNTs into 3D metal-based scaffolds using MED-3D.