Comparative study of the oxidation and hot corrosion behaviors of TiAl-Cr intermetallic alloy produced by electric current activated sintering

Ti-48Al-10Cr (at.%) intermetallic alloy was produced by electric current assisted sintering (ECAS) technique. The oxidation and hot corrosion behaviors of intermetallic alloys were investigated in the cyclic conditions at 700, 800 and 900 degrees C for 180 h in the air. The hot corrosion was realized in the Na2SO4 salt. X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM) equipped with an energy-dispersive spectroscopy (EDS) were used to identify the phase compositions and microstructures of the layers formed on the samples oxidized and hot corroded. The oxidation tests results were showed parabolic behaviors for all test temperatures. In the surface of the corroded samples was observed the separations from porous scale which was composed of Na2Ti3O7, TiO2, Al2O3 and minor phase of TiS. The alloys showed good hot corrosion resistance up to 800 degrees C in the Na2SO4 while the samples showed that weak hot corrosion resistance when the salt was molten at 900 degrees C. In addition, the hot corrosion mechanism was debated on the basis of basic, acidic and synergistic fluxing model. (C) 2018 Elsevier B.V. All rights reserved.https://doi.org/10.1016/j.jallcom.2018.11.32