Frictional ignition of Ti40 fireproof titanium alloys for aero-engine in oxygen-containing media

Abstract The effect of friction pressure p and oxygen concentration x O on the fireproof performance of Ti40 titanium alloy was studied by frictional ignition test, the p — x O relationship quantitatively describing the fireproof performance of Ti40 was established and the fireproof mechanism of Ti40 was analyzed by SEM, XRD and EDS. The results show that the p — x O relationship of Ti40 obeys parabolic rule. The varying range of x O is about 25% while p varies within 0.1-0.25 MPa. When x O is ≥70%, Ti40 is ignited immediately at room temperature and develops into continual and steady burning, and the duration of burning is more than 10 s. The fireproof performance of Ti40 is better than TC4 while x O of Ti40 is at least 40% higher than TC4. When x O is low, the fireproof performance of Ti40 is more sensitive to p ; when x O increases, it is more sensitive to x O . The forming of fused oxides of V 2 O 5 , TiO 2 and Cr 2 O 3 with strong inner interaction during friction is the basic reason of high fireproof performance of Ti40.