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

The Al2O3 forming MAX-phase Ti2AlC has potential to be used in the high-temperature combustion chambers of aircraft engines. In this work, Ti2AlC powder was compressed and synthesized by spark plasma sintering (SPS) at 1200 degrees 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 TiO2, with a small amount of alpha-Al2O3 and numerous planar defects. When the oxidation time was increased, some additional oxides such as rutile-TiO2, alpha-Al2O3, TiO2-Al2TiO5, and TiO2-alpha-Al2O3 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.

Automated summary

In this study, Ti2AlC powder was synthesized using spark plasma sintering (SPS) at different time periods and analyzed for its surface morphology, microstructure, elemental distribution, phase transition, and mechanical properties. The results showed that with increased oxidation time, additional oxides such as rutile-TiO2, alpha-Al2O3, TiO2-Al2TiO5, and TiO2-alpha-Al2O3 were formed.