Densification and mechanical properties of novel Al ₄ O ₄ C ceramics by spark plasma sintering with Y ₂ O ₃ addition

Abstract The present study explores the densification and mechanical properties of novel Al 4 O 4 C ceramics, which are enhanced by the incorporation of Y 2 O 3 additives and the utilization of spark plasma sintering. A significant observation was the presence of a native oxide layer on the surface of the Al 4 O 4 C powder, predominantly composed of Al 2 O 3 . Following sintering at 1723 K, Al 4 O 4 C was established as the primary phase, with Al 2 O 3 and Y 3 Al 5 O 12 (YAG) identified as secondary phases. Comprehensive experimental analysis, complemented by molecular dynamics simulations, revealed the mechanism of YAG on the grain growth behavior of Al 4 O 4 C. The findings demonstrated that an optimal Y 2 O 3 content of 3 wt% resulted in a maximum flexural strength of 272 MPa, a fracture toughness of 2.01 MPa·m 1/2 , and a Vickers hardness of 15.1 GPa. This research offers valuable insights into the densification process and the enhanced mechanical properties of ternary carbides, paving the way for their further applications.