Biaxial Fracture Behavior of Polycrystalline Alumina
Fracture behavior under multiaxial stress state of polycrystalline alumina was studied from the view point of an artificial crack propagation and fracture from a natural flaw. The former was studied by mixed-mode fracture toughness tests; asymmetric four-point bending and diametral compression techniques were carried out using precracked and notched specimens. The latter was studied by biaxial fracture tests in compression and torsion loading; multiaxial fracture statistics was applied to the measured fracture envelope. The ratio KIIC/KIC obtained from the biaxial tests was higher than that obtained by the mixed-mode fracture toughness tests. It revealed that the fracture from an artificial flaw does not simulate the fracture from a naturall flaw in polycrystalline ceramics.
Z.Y. Zhong, H. Saka, T.H. Kim, E.A. Holm, Y.F. Han and X.S. Xie
M. Tsukada et al., "Biaxial Fracture Behavior of Polycrystalline Alumina", Materials Science Forum, Vols. 475-479, pp. 1329-1332, 2005