Quantitative analysis on microstructure and high temperature fracture mechanism of 2.6vol%TiBw/Ti6Al4V composites with equiaxed microstructure after heat treatment

In this paper, the 2.6vol%TiBw/Ti6Al4V composites with network architecture were fabricated by hot press sintering (HPS) at 1100 °C for 1 h, and the quantitative relationships between phases and heat treatment temperatures were established. The results showed that the volume fraction phases changed linearly with a range of solution temperature (930–1010 °C) and aging temperature (400–600 °C). Moreover, the composites with equiaxed microstructure were obtained due to the static recrystallization after solution treated at 950 °C for 1 h and aging treated at 600 °C for 12 h. The ultimate high temperature tensile strengths were 772, 658, 392 and 182 MPa, and the elongations were 9.1%, 12.5%, 28.6% and 35.3% at 400, 500, 600 and 700 °C, respectively. In addition, fractured morphology analysis indicated the excellent strengthening effect of TiBw at a temperature below 600 °C. However, the strengthening effect was significantly reduced due to the debonding of matrix and TiBw at 700 °C and caused the cracks to propagate along the grain boundary.