Optimization of Al6061 Nanocomposites Production Reinforced with Multiwalled Carbon Nanotubes

This study investigates the impact of multi-walled carbon nanotubes (MWCNTs) on the microstructure and mechanical properties of Al6061 nanocomposites. The MWCNTs were uniformly dispersed in the aluminum alloy matrix using ultrasonication following cold pressing and sintering in a vacuum. The effect of the sintered temperature on the microstructure and mechanical properties of the nanocomposites was evaluated. The addition of MWCNTs resulted in grain refinement, with the nanocomposites exhibiting smaller and more uniformly distributed grains than the pure Al6061 matrix, particularly at lower sintering temperatures of 580 and 600 °C. The nanocomposites also demonstrated an increase in hardness, with peak values observed at 580 °C, primarily due to the effective dispersion of MWCNTs, which restrict dislocation movement and reinforce grain boundaries. While higher sintering temperatures led to significant grain growth and less uniform hardness distribution, lower temperatures favored finer grain structures and more homogeneous hardness profiles. The results suggest that the optimal sintering temperature for achieving the best balance between microstructure and mechanical properties is 580 °C. However, the study also highlights the need for optimized dispersion techniques to achieve a more uniform distribution of MWCNTs.