Investigation of Cyclic Oxidation Behavior of (Cr, Mo, Si)-Containing (α2 + γ) TiAl-Based Alloys Synthesized by ECAS Sintering

Ti–48Al–2Cr–2Mo–(0 and 0.5 at %) Si intermetallic alloys were synthesized by electric current- assisted sintering (ECAS). Microstructures of the alloys were characterized using scanning electron microscopy (SEM), electron diffraction spectroscopy (EDS), and X-ray diffraction (XRD) methods of analysis. It was found that the microstructures of the produced alloys consist of α2-Ti3Al and γ-TiAl phases. The cycle oxidation behaviors of the alloys were carried out between 700 and 900°C temperatures for 180 h in air. The oxide scale has comprised the TiO2 and Al2O3 mixture layer, intermediate Al2O3 layer, and outermost TiO2 layer. The oxidation rate constants and activation energies of the alloys were calculated.