Effect of particle size on the fabrication of copper-based nanocomposites via planetary ball mill with DEM simulation

To improve the properties of copper, a copper-based nanocomposite was fabricated using carbon nanotubes (CNTs), with copper powder produced by Steppe Powder LLC. Copper powders with two different raw particle sizes (70 µm and 110 µm) were selected, and various milling parameters, including milling time (1, 3, 6, and 12 hours), rotational speed (100, 300, and 500 rpm), and ball size (5 mm, 10 mm), were adjusted to compare the resulting composite materials. A scanning electron microscope (SEM) was used to analyze particle size and morphology, while a particle size analyzer (PSA) was employed to determine the particle size distribution. A field emission scanning electron microscope (FE-SEM) was used to examine the dispersion of CNTs on the copper particles. Additionally, the discrete element method was applied to study the milling mechanism in the ball milling machine. The results indicated that for a rotational speed of 300 rpm, increasing the milling time led to the flattening and growth of the composite particles, whereas at 500 rpm, longer milling times resulted in more flattened and significantly reduced particle sizes. Regarding CNT dispersion, at 300 rpm with a milling duration of 12 hours, CNTs were weakly attached to the copper surface. In contrast, at 500 rpm for 12 hours, CNTs were successfully embedded into the surface of the copper particles.