Accession Number : AD0819014

Title :   DIFFUSIONAL PRESTRESSING OF CERAMICS.

Descriptive Note : Summary rept. 9 Dec 65-31 Mar 67,

Corporate Author : SOUTHERN RESEARCH INST BIRMINGHAM AL

Personal Author(s) : Bickelhaupt, Roy E. ; Cox, Herbert P. ; Hurst, Robert D.

Report Date : 06 JUL 1967

Pagination or Media Count : 81

Abstract : This report describes an investigation concerning diffusional prestressing of magnesia single crystal tensile specimens. Compressively stressed surface layers were obtained by creating a solid solution of MgO and NiO at the periphery of the specimen. This solid solution possesses a lower coefficient of expansion than the host MgO crystal and acquires a residual stress during cooling from the diffusion anneal temperature. The potential strength enhancement is discussed and an estimation of the magnitude of the effect is given. Several systems were examined with respect to the adaptability to this program. The effect of concentration of solute on the thermal expansion of magnesia solid solutions was investigated. Solute oxides included NiO, MnO, CaO, Li2O, and BeO. The quality of the solid solutions was evaluated by determining by X-ray lattice parameters, and thermal expansion was measured by high temperature X-ray diffraction. The current status of the work indicates that only the MgO-NiO system is suitable for the mechanical portion of this program.

Descriptors :   *TENSILE PROPERTIES), (*STRESSES, CERAMIC MATERIALS), (*CERAMIC MATERIALS, (*SURFACE PROPERTIES, STRESSES), MAGNESIUM OXIDES, OXIDES, ANNEALING, DIFFUSION, CRACK PROPAGATION, DEFECTS(MATERIALS), THERMAL EXPANSION, PHOTOMICROGRAPHY, SINGLE CRYSTALS, SOLID SOLUTIONS, NICKEL COMPOUNDS, MANGANESE COMPOUNDS, CALCIUM OXIDES, LITHIUM COMPOUNDS, BERYLLIUM OXIDES, CRYSTAL LATTICES, X RAY DIFFRACTION, TABLES(DATA).

Subject Categories : Ceramics, Refractories and Glass
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE