Accession Number:

AD0707447

Title:

STRENGTHENING OXIDES BY REDUCTION OF CRYSTAL ANISOTROPY.

Descriptive Note:

Technical rept.,

Corporate Author:

CERAMIC FINISHING CO STATE COLLEGE PA

Report Date:

1970-04-01

Pagination or Media Count:

55.0

Abstract:

Literature information was used to demonstrate that the grain size dependence of strength increases with increasing crystal anisotropy in well-made pure oxide ceramics. Based upon this information a large grain size dependence of strength was predicted for rutile TiO2 bodies. This dependence was verified by experiment. The lack of strength at large grain size was attributed to the presence of localized cracks formed by relief of stresses caused by thermal expansion anisotropy. The lengths of these cracks were measured and were used to calculate the strengths of the bodies using the Griffith theory. Solid solution compositions with reduced thermal expansion anisotropy were available from previous investigations. Ceramic bodies of these compositions were prepared by hot pressing. Specimens of various average grain sizes were prepared and the strength vs. grain size was determined. The weight of the evidence available at present indicates that the grain size dependence of strength of the solid solutions with reduced thermal expansion anisotropy is less than that of the comparable pure oxides. Author

Subject Categories:

  • Ceramics, Refractories and Glass

Distribution Statement:

APPROVED FOR PUBLIC RELEASE