Abstract:Near-α titanium matrix composites reinforced with TiB and La₂O₃ were synthesized by common casting and hot-working technology. The effects of β heat treatment temperature on the microstructure and the tensile properties of the in situ synthesized (TiB+La₂O₃)/Ti were studied. Microstructure was studied by OM and TEM, and tensile tests were carried out at room temperature and 923 K, respectively. Results show that with the increase of β heat treatment temperature, prior β phase grain size increases and α colony size decreases. Room temperature tensile strength increases with the increase of β heat treatment temperature, which can be attributed to the decrease of α colony size with the increase of β heat treatment temperature. However, high-temperature tensile strength decreases with the increase of β heat treatment temperature and the decrease of the high-temperature tensile strength is due to the increase of the prior β phase grain size.

Key words: titanium matrix composites; microstructure; mechanical properties