Improving high temperature oxidation resistance of TiAl alloy via hierarchical Ti5Si3-Ti2AlC precipitation strategy

In -situ precipitated ceramic particles with excellent oxidation resistance acted as a barrier, which can improve the high temperature oxidation resistance of TiAl alloys. Herein, hierarchical Ti5Si3-Ti2AlC particles reinforced TiAl composite was designed and prepared by spark plasma sintering, where micron-Ti5Si3 particles were mainly precipitated at grain boundaries, and nano-Ti2AlC particles were mainly precipitated at the interfaces of alpha 2/gamma lamellae. The mass gain of TiAl alloy was decreased by 38.5% after oxidation at 850 degrees C for 100 h. The various atoms inward and outward diffusion were inhibited by the hierarchical micron-Ti5Si3 and nano-Ti2AlC particles, which suppressed TiO2 fast-growing and promoted Al2O3 slow-growing.