Thermal stability and creep behavior of Ti-V-Cr burn-resistant alloys

The thermal stability and creep behavior of Ti-35V-15Cr (35V alloy) and Ti-25V-15Cr (25V alloy) burn-resistant titanium alloys are researched. The results show that post-exposure tensile properties deteriorated with the increase in exposure temperature (450-600 °C). The decrease in tensile properties of the 35V alloy results from the combination of surface oxidation and microstructural changes and the decrease in tensile properties of the 25V alloy results from surface oxidation. The main change of the microstructure during thermal exposure is the heterogeneous precipitation of α phase on β grain boundaries. Increased vanadium content in the alloy shows an adverse effect on alloys' thermal stability. The creep resistance of the 35V alloy is little better that that of the 25V alloy. During creep exposure at 540 °C for 100 h, the heterogeneous precipitation of α phase on β grain boundaries in 35V alloy strengthens the grain boundary, leading to increases in the creep resistance, while the heterogeneous precipitation of α phase in grains and grain boundaries in the 25V alloy is rod-like, leading to decreases in the creep resistance.