Low volume fraction in situ (Ti5Si3 + Ti2C)/Ti hybrid composites with network microstructure fabricated by reaction hot pressing of Ti–SiC system

In situ hybrid Ti5Si3 rods and Ti2C particles reinforced pure titanium matrix composites ((Ti5Si3 + Ti2C)/Ti) with a low volume fraction of reinforcements and a novel network microstructure were successfully fabricated by reaction hot pressing (RHP) of the Ti–SiC system. In order to tailor the network microstructure, large spherical pure Ti particles and fine SiC particles were selected followed by low energy ball milling and reaction hot pressing. Ti5Si3 rods and Ti2C particles were in situ synthesized by the reaction between the Ti and SiC phases and dispersed around the large pure Ti particles forming a unique network microstructure. The yield strength or ductility of the fabricated composites were remarkably improved by tailoring a novel network microstructure and introducing in situ hybrid reinforcements. In particular, both the strength and the ductility of the composite, having 1 vol.% reinforcement, are significantly enhanced compared with that of monolithic pure Ti. This can be attributed to formation of the network microstructure, matrix grain refinement and synthesis of in situ hybrid reinforcements. Furthermore, with increasing volume fraction of reinforcements above 1 vol.%, an increased strength and a decreased ductility were observed.