Mechanical properties and oxidation behavior of the Ti–24Al–14Nb–3V–0.5Mo alloy sheet

Tensile properties of the Ti–24Al–14Nb–3V–0.5Mo alloy (at.%) solution treated at 1000 °C after hot-rolling was studied in the temperature range between room temperature and 700 °C. The tensile strength was sensitive to the test temperature and was decreased as the temperature increased from 200 to 500 °C. Tensile strength of the alloy at room temperature initially increased gradually with an increase in the strain rate from 8.3 × 10−4 to 0.33 s−1 followed by a slow hardening with increasing the strain rate to 8.3 × 10−1 s−1. The alloy exposed at 700 °C showed the best oxidation resistance due to the formation of a continuous α-Al2O3 layer in the scale. However, the beneficial doping effect of Nb addition on the oxidation resistance above 700 °C was probably overlaid by fast internal diffusion of oxygen, which was proved by a thick transitional layer beneath the scale in the specimen exposed at 800 °C.