Fracture Resistance of Highly Textured Alumina

• Published in: Journal of the American Ceramic Society 2001-07, Vol.84 (7), p.1514-1520
• Main Authors: Hall, Peyton W., Swinnea, J. Steven, Kovar, Desiderio
• Format: Article
• Language: English
• Subjects: alumina; Applied sciences; Building materials. Ceramics. Glasses; Ceramic industries; Chemical industry and chemicals; Exact sciences and technology; fracture mechanics/toughness; Structural ceramics; tape casting; Technical ceramics; texture
• ISSN: 0002-7820; 1551-2916
• DOI: 10.1111/j.1151-2916.2001.tb00870.x

Textured alumina has been fabricated previously by either hot‐deformation processing, to produce moderate texture, or templating with aligned platelets, to produce stronger texture. Fracture‐toughness measurements on ceramics fabricated by hot deformation have indicated only a modest improvement in toughness compared with that of untextured ceramics, while measurements on more strongly textured ceramics have been very limited. In this work, a simplified process for fabricating highly textured alumina was developed, using a solvent‐based slurry, tape casting, and liquid‐phase sintering. Grain size was tailored to maximize the likelihood of grain bridging and crack deflection. Image analysis was used to characterize morphologic texture, and X‐ray pole‐figure analysis was used to measure crystallographic texture. Fracture tests revealed significant changes to the crack path as a result of the texture. However, the apparent fracture resistances measured using single‐edge notched‐beam samples were similar for textured and untextured ceramics. The lack of apparent toughening resulting from texturing is discussed in light of previous results.