Microstructures, Properties and Strengthening Mechanisms of Titanium Matrix Composites Reinforced by In Situ Synthesized TiC and Unreacted Carbon Nanotubes

Carbon nanotubes (CNTs) are regarded as an excellent reinforcement for reinforcing metal matrix composites. However, they are extremely difficult to disperse since nano-scaled CNTs have large specific surface area, generally leading to agglomeration due to the large van der Waals attractive forces. In this study, CNTs as carbon sources were added into Ti6Al4V matrix, a dry jar-milling process without milling balls was performed to greatly reduce the structural damage of CNTs and simultaneously meet the requirements of dispersion homogeneity. In situ synthesized TiC and unreacted CNTs reinforced Ti6Al4V matrix composites (TMCs) were successfully prepared by the fast manufacturing process via spark plasma sintering. The microstructures and mechanical properties including microhardness, compressive yield strength, ultimate compressive strength and plastic strain of the Ti6Al4V alloy and the TMCs prepared by different CNTs content were studied to evaluate the strengthening effects of the reinforcements on Ti6Al4V matrix.