Microstructure and mechanical properties of Al2O3/Al2O3 composite densified through a slurry infiltration and sintering process

High fracture strength and fracture toughness are vital requirements for the Al2O3/Al2O3 composites. This advanced structural material is composed of two-dimensional alumina fiber fabrics with porous alumina matrices. However, the Al2O3/Al2O3 composites exhibit low delamination resistance under shear stress. In this study, an as-fabricated Al2O3/Al2O3 composite was densified through a slurry infiltration and sintering (SIS) process. The SIS-cycle-dependent mechanical properties of the Al2O3/Al2O3 composites were investigated. The results showed that the matrix was strengthened, and the fibers were unaffected after SIS process. With increasing SIS cycles, the flexural and interlaminar shear strengths increased, whereas the fracture toughness decreased. The best performance was reached after six SIS cycles, which had a flexural strength of 414.7 +/- 41.6 MPa, an interlaminar shear strength of 25.6 +/- 3.1 MPa, and a fracture toughness of 11.0 +/- 0.3 MPa m1/2. The different changes in fracture strength and fracture toughness with the SIS cycles were attributed to matrix densification and enhanced interfacial bonding. The SIS process has the potential to improve the strength without sacrificing the damage tolerance.(c) 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).