Abstract
This study investigated the thermal diffusivity behaviours of spark plasma sintered
(SPS) multi-walled carbon nanotubes (MWCNTs) reinforced Ti6Al4V composites containing 0,
1, 2 and 3 wt. % of the reinforcement respectively, over a range of 50 – 300 °C. The MWCNTs were
dispersed into the Ti6Al4V matrices by high-energy ball milling (HEBM) technique and the milled
composite powders were consolidated by SPS under a vacuum atmosphere. The sintering conditions
employed were heating rate (100 °C/min), holding time at temperature (5
min), sintering temperature (850 °C) and applied pressure of 50 MPa. The relative densities of the
composite discs were measured according to Archimedes’ principle while the thermal diffusivities of
as-sectioned composite samples were measured using the Laser Flash equipment. Relative densities of
the synthesized nanocomposites deteriorated with increase in the weight fraction of MWCNTs added to
Ti6Al4V. The thermal diffusivities of the composites containing
1 and 2 wt. % MWCNTs improved with increase in temperature and weight fraction of MWCNTs contents.
A reverse trend was observed in the composite containing 3 wt. % MWCNTs, as the measured thermal
diffusivities continued to drop with increase in temperature. Although this composite exhibited the
best thermal diffusivities compared to the other composites up to 200 °C, a significant drop in
thermal diffusivity was recorded between 250 and 300 °C respectively with the values lower than
that of the unreinforced Ti6Al4V alloy. However, the thermal diffusivities of MWCNTs/Ti6Al4V
composites were generally not dependent on their densification as the composites with higher weight
fractions of the reinforcement had higher
thermal diffusivities in spite of their lower relative densities.