Fabrication and mechanical properties of the titanium matrix composites based on Ti6Al4V-ZrB2-(Si) system

In this work, series of Ti matrix composites based on the Ti6Al4V-ZrB2-(Si) system were successfully fabricated through powder metallurgy. The room-temperature tensile strengths were significantly enhanced to 1063 MPa and 1185 MPa with 4.5 wt% and 9 wt% ZrB2 addition, respectively. The high-temperature tensile strength was enhanced to 501 MPa (600 °C) and 327 MPa (700 °C) for Ti64-4.5 wt%ZrB2 composite, and 693 MPa (600 °C) and 422 MPa (700 °C) for Ti64-9 wt%ZrB2 composite. As for the creep resistance, the Ti64-9 wt%ZrB2 composite exhibited the lowest steady-state creep rate of (4.88 × 10-7 s-1) and the longest creep time to rupture (6.28 h). Adding Si to construct the two-scale network structure further enhanced the mechanical properties, especially at high temperature, the strengths were elevated by 26% and 39% for the Ti64-4.5 wt%ZrB2-1wt.%Si composite at 600 °C and 700 °C, respectively, and the creep resistance was markedly enhanced with the help of the second-scale silicide reinforcement network.