Analysis of the influence mechanism of high temperature creep behavior difference between TiBw/TA15 and TiBw/Ti65 composites

To fully utilize the persistent performance of composites with TiBw whiskers (TiBw) distributed along the network, the creep resistance mechanisms of two rolled composites (TiBw/TA15 and TiBw/Ti65) with different matrices were thoroughly investigated. The creep properties of the two composites under different temperatures and stress conditions were comparatively analyzed by high-temperature (HT) creep tests. The fracture mechanism and microstructure evolution of rolled composites during HT creep were summarized. The results indicate that in the range of 600–650 °C, the creep mechanism of TiBw/TA15 was controlled by dislocation movement, while TiBw/Ti65 was controlled by dislocation climb. The creep life of rolled TiBw/TA15 can exceed 100 h (h) under conditions of 600 °C/250 MPa and 650 °C/150 MPa. Under the same stress, the creep resistance temperature of rolled TiBw/Ti65 was about 50 °C higher than that of TiBw/TA15, that is, the creep life can exceed 100 h under conditions of 650 °C/250 MPa and 700 °C/150 MPa. During the creep process, the voids at the interface between TiBw and the matrix exhibited, which were mainly distributed along the loading direction. As the deformation increased, the number of small voids increased and merged to form larger voids or cracks, ultimately leading to material fracture. The addition of TiBw and silicide effectively decreased the creep rate by impeding dislocation movement, leading to an enhancement in the creep resistance of the composites. The relatively stable interface between the silicide and the matrix hindered micropore formation, thereby maintaining favorable deformation coordination during the creep process and enhancing stability in resisting creep.