Accession Number : AD0673835

Title :   RELATION OF MECHANICAL PROPERTIES TO THE STRUCTURE OF IONIC SOLIDS.

Descriptive Note : Quarterly rept. no. 8, 1 Mar-31 May 68,

Corporate Author : PENNSYLVANIA STATE UNIV UNIVERSITY PARK MATERIALS RESEARCH LAB

Personal Author(s) : Vedam,K. ; Newnham,R. E.

Report Date : 20 JUN 1968

Pagination or Media Count : 29

Abstract : Experiments to cement the thin mica flakes to various materials for making reproducible microhardness measurements on them, were not successful. Hence, a suitable jig has been designed to hold the thin flakes firmly to the base, and is currently under fabrication. From an analysis of the crystal structures of the various micas two equations were obtained which can be used to predict the tetrahedral rotation angles alpha and the differences (Delta) between the outer and inner interlayer cation-oxygen distances from chemical composition data only. It was found that Delta is a linear function of alpha which is predominantly controlled by the tetrahedral-octahedral sheet misfit. Finally, it is suggested that barium restricts the formation of random stacking faults in much the same way as basal plane corrugation in dioctahedral micas. (Author)

Descriptors :   (*MICA, MECHANICAL PROPERTIES), (*SILICATES, CRYSTAL STRUCTURE), HARDNESS, TEST METHODS, JIGS, DISLOCATIONS, CRYSTAL LATTICES, BARIUM COMPOUNDS, LITHIUM COMPOUNDS, MAGNESIUM COMPOUNDS, ALUMINUM COMPOUNDS, FLUORIDES, CERAMIC MATERIALS, SIMULATION

Subject Categories : Ceramics, Refractories and Glass
      Crystallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE