Identifying and understanding the effect of milling energy on the synthesis of carbon nanotubes reinforced titanium metal matrix composites

The influence of milling energy on the dispersion and evolution of multi-walled carbon nanotubes (MWCNTs) in titanium (Ti) metal matrix composites (TMCs) prepared via powder metallurgy has been investigated. High energy ball milling (HEBM) was employed to disperse MWCNTs (0.5 wt.%) into Ti matrix in two controlled ball milling processes: with and without in-situ formation of titanium carbide (TiC). Both types of the powder mixtures were then pressed under 40 MPa into green compacts and sintered in a high vacuum furnace at 1100 degrees C for 2 h. The evolution of MWCNTs during the fabrication process and the mechanical properties of the sintered composites were discussed in conjunction with the in-situ formation of nano-crystalline TiC. The mechanical properties of the composites consolidated from the powder mixtures with in-situ formed TiC during HEBM were significantly enhanced as opposed to composites consolidated from the powder mixtures without formation of TiC during HEBM.