Cyclic Oxidation and Diffusion-Controlled Performance of Ti2AlC MAX-Phase Produced by Spark Plasma Sintering

The AI2O3 forming MAX-phase TiyAlC has potential to be used in the hightemperature combustion chambers of aircraft engines. In this work, Ti2AlC powder was compressed and synthesized by spark plasma sintering (SPS) at 1200°C and 30 MPa for different periods of time. The surface morphology, cross-section microstructure, mapping elemental distribution analysis, phase transition analysis, and mechanical properties were analyzed using a scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and nanoindentation techniques. The results revealed that between 24 h and 100 h, Ti2AlC structure was primarily composed of rutile TiO2j with a small amount of a-Al2Og and numerous planar defects. When the oxidation time was increased, some additional oxides such as rutile-TiO2, aAl2Og, TiO2-Al2TiO5, and TiO2-a-Al2Og were also formed. Although the planar defects were reduced at 300 h due to the inward diffusion of O2 and outward diffusion of Al3+ and Ti4+, they spread throughout the entire structure rather than forming layers, leading to a significant loss in oxidation resistance.