Abstract
Negligible work has been reported on exploring the machinability aspects of titanium-based nanocomposites. High-density graphene nanoplatelets (GNPs) reinforced Ti6Al4V matrix nanocomposites are developed by using a high-frequency induction heating technique. The nanocomposites are developed with different percentages of GNPs, including 0 wt.% (base-Ti6Al4V), 0.3 wt.%, 0.6 wt.%, and 1.2 wt.% (GNPs/Ti6Al4V). Afterward, the machining behavior of the Ti6Al4V nanocomposites is investigated in detail during milling in terms of the cutting force components, surface roughness, surface morphology, microhardness and chips morphology. The milling results show that the addition of GNPs reinforcements considerably affects the machining performance of the nanocomposites. Even with high hardness, the 0.3 wt.% and 1.2 wt.% GNPs/Ti6Al4V nanocomposites showed lower cutting forces than the base-Ti6Al4V, i.e., leading to energy conservation. This is mainly due to the profound effect of the GNPs on the hardness, microstructure, and developed phases (TiC and graphene agglomeration) in the nanocomposites. Despite having a higher hardness, all the GNPs/Ti6Al4V nanocomposites revealed improved surface morphology as compared to the base-Ti6Al4V samples. For instance, at a high feed rate of 210 mm/min, the nanocomposites with 0.3 wt.%, 0.6 wt.%, and 1.2 wt.% GNPs contents exhibited approximately 39%, 13%, and 24%, respectively, lower roughness as compared to the base-Ti6Al4V. The 1.2 wt.% GNPs/Ti6Al4V samples show the lowest increase (3.2%) in the surface hardness even after machining at a higher cutting speed of 75 m/min. In comparison, the base-Ti6Al4V samples, which have lower (8.6%) initial hardness, exhibit an increase of 12.7% in surface hardness after machining at the same cutting speed (75 m/min). Overall, the 0.3 wt.% and 1.2 wt.% GNPs nanocomposites are close contestants for yielding the lower cutting forces, improved surface roughness, lower variation in the machined surface hardness, and smoother surface quality with minimum defects in most of the milling conditions, i.e., leading to sustainable machining and clean environment.