Grain size effect on cyclic oxidation of (TiB2+TiC)/Ni3Al composites

(TiB2+TiC)/Ni3Al composites were prepared by mechanical alloying of elemental powders and subsequently spark plasma sintering. Microstructure of (TiB2+TiC)/Ni3Al composite sintered at 950 °C was finer than that of composite sintered at 1050 °C. The influence of grain size on cyclic oxidation behavior was investigated. Cyclic oxidation results showed that the composite sintered at 950 °C had smaller mass gains than the composite sintered at 1050 °C. XRD and EDS results indicate that finer grain size is beneficial for increasing the oxidation resistance by improving the formation of a continuous TiO2 outer layer and a continuous Al2O3 inner layer on the surface of the composites sintered at 950 °C.