• Ti 3 AlC 2 crystal orientation affects the anisotropic oxidation pathways. • The addition of Al 2 O 3 filler improve the formation of the α-Al 2 O 3 layer. • An anomalously high n-value (>4) signifies strongly decelerated oxidation behavior at 1000 °C. • The oxidation kinetic law is from complex to initial competitive oxidation . The application of Ti 3 AlC 2 is constrained by the inherent contradiction between its strength and toughness. Introducing texture and Al 2 O 3 as reinforcements is an effective strategy to address this challenge. However, the influence of crystallographic orientation and reinforcement phase on its high-temperature oxidation behavior has not been fully studied. In this work, the high-temperature oxidation behavior of texture Ti 3 AlC 2 /Al 2 O 3 composite was systematically investigated. And the effect of crystallographic orientation and exogenous Al 2 O 3 particles during the oxidation were further analyzed. The study demonstrated that Ti 3 AlC 2 /Al 2 O 3 composite exhibited an abnormal kinetic behavior with an oxidation index n > 4, which indicated the materials possess the excellent oxidation resistance. The Ti 3 AlC 2 /Al 2 O 3 composite exhibited oxidation anisotropy at different crystal orientation. Furthermore, the high content of Al 2 O 3 promoted preferential formation and densification of the protective α-Al 2 O 3 layer. As a result, the oxidation behavior of Ti 3 AlC 2 /Al 2 O 3 composite deviated from simple conventional kinetics and showed a complex transition process from competitive oxidation to diffusion control. This study enhances the comprehension of the oxidation behavior of textured MAX phase composites, providing a theoretical basis for their microstructural design and life prediction in high-temperature applications.
Xue et al. (Fri,) studied this question.