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 degrees 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 degrees C) and aging temperature (400-600 degrees C). Moreover, the composites with equiaxed microstructure were obtained due to the static recrystallization after solution treated at 950 degrees C for 1 h and aging treated at 600 degrees 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 degrees C, respectively. In addition, fractured morphology analysis indicated the excellent strengthening effect of TiBw at a temperature below 600 degrees C. However, the strengthening effect was significantly reduced due to the debonding of matrix and TiBw at 700 degrees C and caused the cracks to propagate along the grain boundary.

Automated summary

The study fabricated 2.6vol% TiBw/Ti6Al4V composites with a network architecture through hot press sintering at 1100 degrees C for 1 hour, establishing quantitative relationships between phases and heat treatment temperatures. It was found that the volume fraction phases changed linearly with solution and aging temperatures, resulting in equiaxed microstructure composites with different high temperature tensile strengths and elongations. Fractured morphology analysis indicated the strengthening effect of TiBw at lower temperatures, but debonding at 700 degrees C significantly reduced this effect.