Chai Lihua

STUDY ON CYCLIC OXIDATION RESISTANCE OF HIGH NIOBIUM CONTAINING TiAl BASE ALLOY WITH ERBIUM

Ti-46Al-8Nb and Ti-46Al-8Nb-0.1Er alloys were prepared by the cold crucible induction levitation melting method.The oxidation behavior experiment was done in air at 900℃ up to one hundred times.Based on the oxidation kinetic analysis and the phase constitution,microstructure and the interface of the oxidation film and the matrix were investigated by means of XRD and SEM equipped with EDS,the cyclic oxidation resistance of TiAl based alloys was explored.The results showed that no spallation of layer occurs in both alloys,and Ti-46Al-8Nb-0.1Er comparing with Ti46Al-8Nb exhibits more excellent oxidation resistance,oxides formed on the surface consist of mainly Al_2O_3,the continuous compact oxidation film with a good combination with the matrix significantly decreases the oxidation rate,the mass gain and the oxide film thickness.The addition Er purifies the alloy matrix and prevents the inward diffusion of oxygen atoms,thereby improves the cyclic oxidation resistance of TiAl based alloy.