Conclusion
High quality dispersion was achieved using ZW surfactant, resulting in undamaged CNT surfaces. Ni–CNT composite
powders were successfully consolidated by SPS at 650 _C. Room temperature tensile tests indicate high strength in all
consolidated bulk samples, with Ni samples consolidated at 550 _C obtaining the highest average strength and ductility.
Ni–CNT specimens showed increased Vickers hardness and comparable tensile strength when compared to Ni
specimens with the same grain size, and notable decrease in ductility. The hardness results agree with the anticipated
increase in mechanical behavior as a result of CNT addition. Lower than expected strength and ductility was
observed, which are attributed to a weak interface between the Ni matrix and CNT resulting in lower than expected load transfer. A shear-lag model where the operative reinforcement length is less than the calculated critical
reinforcement length is thought to be a more appropriate model given the UFG nature of the Ni matrix used in this study.