Fracture Behavior of Alumina/Monazite Multilayer Laminates

• Published in: Journal of the American Ceramic Society Vol. 83; no. 4; pp. 802 - 808
• Main Authors: Mawdsley, Jennifer R., Kovar, Desiderio, Halloran, John W.
• Format: Journal Article
• Language: English
• Published: Westerville, Ohio American Ceramics Society 01.04.2000; Blackwell
• Subjects: Applied sciences; Building materials. Ceramics. Glasses; Ceramic industries; Chemical industry and chemicals; debonding; Exact sciences and technology; fracture; laminates; Structural ceramics; Technical ceramics; Bending strength; Interface properties; Stratified material; Fracture mechanics; Lanthanum Phosphates; Mechanical properties; Experimental study; Alumina; Sliding friction; Composite material; Structural ceramic
• ISSN: 0002-7820; 1551-2916
• DOI: 10.1111/j.1151-2916.2000.tb01278.x

Monazite (LaPO4) has been proposed as an interphase to promote debonding between the reinforcement and the matrix during the fracture of oxide‐based composites. The correlation between fracture behavior and micromechanical properties in model alumina/monazite (Al2O3/LaPO4) multilayer laminates has been investigated in this study. The delamination fracture energy (Γi) was dependent on crack length, which is consistent with previous results; the initial value of Γi was ∼10 J/m2. The interfacial frictional sliding resistance increased as the normal stress on the interface increased. Using a Coulombic friction model, the coefficient of static friction between the Al2O3 and LaPO4 layers was determined to be 0.63. The influence of Γi and flaw size in the Al2O3 layers on fracture path has been predicted, using an existing model, and confirmed experimentally. The results indicate that, in addition to satisfying energy‐based fracture criteria, several other factors affect whether LaPO4 is a suitable interphase for oxide composites.