Creep behavior and microstructure evolution of titanium matrix composites reinforced with TiB, TiC and Y2O3
(1. National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin 150001, China;
2. School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China)
2. School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China)
Abstract: Titanium matrix composites reinforced with (TiB + TiC) and (TiB + TiC + Y2O3) were prepared by induction skull melting. The creep test was carried out at 650 °C and 120-160 MPa, and the microstructure evolution was characterized in detail by XRD, SEM and TEM. The results show that the microstructure of the two composites is basket-weave structure. Under the same creep condition, the composite with the addition of Y2O3 has lower steady-state creep rate. After creep, silicides precipitated at the α/β interface, around dissolved β phases and reinforcements, which have a strong pinning effect on the dislocation movement. Due to the stacking fault structure through TiB whisker, the size of silicides around TiB is significantly larger than that around TiC and Y2O3. Solute-drag creep is the main creep mechanism, and the dislocation movement is also affected by α/β interface, reinforcements and silicides.
Key words: titanium matrix composite; microstructure; creep behavior; silicide