Enhanced ambient temperature creep resistance of α/β-Ti alloys induced by minor Fe

It is generally accepted that the addition of Fe deteriorates the creep behavior of titanium alloys at elevated temperature. However, the effect of Fe at ambient temperature is not well documented. In this paper, the creep performance of an α/β titanium alloy with different Fe contents (0.05 and 0.20 wt%) was systematically studied at temperatures from the ambient to 500 °C. Creep resistance of samples with 0.20 wt% Fe was found to decrease at temperatures above 300 °C, but to increase at ambient temperature and 200 °C. The resulting stress exponent was in the range of 4.7-14.4, corresponding with dislocation creep. The fitted creep activation energy fell into two categories, i.e., 1) comparable with the self-diffusion activation energy of α-Ti at elevated temperature, and 2) remarkably higher than the former at 200-400 °C. The underlying mechanisms controlling creep processes at different temperatures were discussed.