Accession Number : AD0430069

Title :   ATOMISTIC EXPRESSION OF HARDNESS,

Corporate Author : AIR FORCE CAMBRIDGE RESEARCH LABS L G HANSCOM FIELD MASS

Personal Author(s) : Plendl,J. N. ; Gielisse,P. J.

Report Date : FEB 1963

Pagination or Media Count : 28

Abstract : Hardness of nonmetallic solids, define as resistance against structure break-down, has been re-examined for eighty-eight solids of twenty-two different structures. The validity of the previously proposed volumetric cohesive energy, U/V, as a direct measure of hardness, has been more fully substantiated by additional data. The essential subdivision of solids into hard core and soft core could be more clearly defined. A formula is proposed which expresses hardness in terms of physical constants and measurable physical parameters only. The formula shows hardness to be directly proportional to the force constants, a structure factor and the effective valency but inversely proportional to the interatomic distance. This formulation has a direct bearing on problems, such as hardness anisotropy and solid solution hardness. (Author)

Descriptors :   (*HARDNESS, NONMETALS), THEORY, MECHANICAL PROPERTIES, CRYSTAL LATTICES, ENERGY, SOLID STATE PHYSICS

Distribution Statement : APPROVED FOR PUBLIC RELEASE