Microstructure–mechanical properties correlation in spark plasma sintered Ti–4.8 wt.% TiB₂ composites

Ti–TiB₂ composites were fabricated from powder mixtures via spark plasma sintering method. Mechanical behavior of the sintered composites were then investigated via both routine and nanoindentation methods. Results indicated a significant increase in ultimate tensile strength and hardness of the composite, when the sintering temperature is raised. Besides common increase in the relative density of the composite, such a behavior was also attributed to the higher amounts of in-situ formed TiB whiskers. The remarkable reduction in bending strength is probably due to limited formability of unreacted coarse TiB₂ particles and agglomerated in-situ formed phases. Such findings were then discussed in detail, based on the nanomechanical behavior of the primary and in-situ formed phases in Ti–TiB₂ composite sintered at 1200 °C. It was concluded that the superiority of mechanical properties in the mentioned sample may be due to high strength primary and in-situ formed reinforcements distributed homogenously in the matrix. Such reinforcement also provided high strength interfaces, according to interfacial nanoindentation approaches.