Investigation of thermal stability of aluminum matrix nanocomposites using functionalized MWCNTs

This work investigates the thermal stability of aluminum matrix nanocomposites reinforcing with functionalized multi-walled carbon nanotubes (MWCNTs). The effect of the chemical functionalization of MWCNTs (MWCNTs-COOH) was evaluated on the microstructure of these nanocomposites. One of the main challenges in producing metal matrix nanocomposites is obtaining a uniform dispersion of the reinforcement. The use of MWCNTs-COOH significantly impacted aluminum matrix nanocomposites' microstructure and mechanical properties. The nanocomposites produced with functionalized MWCNTs exhibit uniform dispersion, resulting in smaller grain sizes. However, concerning dislocation density and texture, the nanocomposites produced with non-functionalized MWCNTs exhibit a higher dislocation density and a different crystallographic orientation. For the heat-treated nanocomposites, it was observed that the reinforcement affects the recovery and recrystallization processes. This effect is more significant for nanocomposites produced with functionalized CNTs, resulting in a microstructure characterized by a significant fraction of deformed grains, smaller grain sizes, and higher mechanical properties.