Abstract
The effects of C and Al concentrations on the specific resistance and rigidity of newly developed ultra-high strength titanium-based metal matrix composites (Ti-MMCs), fabricated using blended elemental reactive sintering (BERS), were investigated. Both TiC(1−X)/Ti–6Al–4V and Ti–8.6Al–5.7V composites were compared with TiB/, SiC/ and AlN/Ti-MMCs. TiC was found to react with Ti powder and to transform to TiC(0.50–0.62) during sintering. The resulting TiC(0.50–0.62)/Ti–8.6Al–5.7V exhibited a specific resistance of 2.33 µΩm, a Young’s modulus of 135 GPa and a tensile strength of 1.25 GPa, with a substantial elongation of approximately 2.5%. In contrast, TiB/Ti–6Al–4V showed excellent mechanical properties but an extremely low electrical resistance because the conducting TiB particles had a specific resistance of only 0.07 µΩm. Both SiC and AlN also reacted with Ti powder during sintering to form a brittle phase at the interfaces between the particles and the Ti matrix. As a result, Ti–6Al–4V MMCs suitable for use as structural materials could not be fabricated using BERS with SiC or AlN. The high specific resistance of the TiC(0.50–0.62)/Ti–8.6Al–5.7V is partly attributed to the C deficiency of the TiC(0.50–0.62) particles, which results in a specific resistance of approximately 1.7 µΩm. This value is approximately three times higher than the value of 0.52 µΩm for stoichiometric TiC particles. The solubility of excess C and Al in the Ti matrix also increases the specific resistance of the material.
This Paper was Originally Published in Japanese in J. Japan Inst. Met. Mater. 83 (2019) 97–106. The fifth author name was revised from Kiyoji Nakamura to Kiyoharu Nakamura. The bibliography information of an article for correction was listed in J. Japan Inst. Met. Mater. 83 (2019) 256.
