The effect of rare earth (RE) elements addition on the microstructure, high temperature mechanical properties, and oxidation resistance of a ?-stabilized TiAl alloy was investigated by scanning electron microscopy (SEM), high temperature compression and isothermal oxidation tests. SEM and EDS results showed that RE-added alloys contained dispersed particles. Most particles were rich in RE-elements and oxygen, thereby suggesting that solute oxygen atoms in the matrix of alloys were scavenged by RE-elements. With increasing RE-content, mean size of particles was increased; however, the number of particles reached to the maximum values at 0.2 % RE, corresponding to minimum interparticle spacing. Afterwards, as a result of particle coarsening, the number of particles was declined to the lower values. Fine and closely spaced particles in the microstructure of TNM+0.2La and TNM+0.2Er alloys led to retarding dynamic recrystallization and higher peak flow stresses at 900 and 1000 ? C. Also, the results showed that Er-containing alloys possessed a higher flow stress, particularly at 1000 ? C, since the particle size of Er-containing alloys was less than that of La-containing alloys. Oxidation resistance of alloys containing 0.1 % La and Er increased due to reducing diffusion rate in oxidation scale. However, the scale growth rate of TNM+0.2La and TNM+0.2Er were higher than that of TNM alloy.
