Условия Механической Стабильности И Упругие Свойства Кристаллических Структур С Разной Симметрией

Abstract

A critical analysis of the conditions of elastic stability of crystal structures of different symmetry as restrictions imposed on their elastic constants cij has been carried out. It is shown that the conditions of elastic stability of all crystals, except for cubic ones, are described by polynomials from the second to sixth powers of their elastic constants cij. Necessary and sufficient conditions for the elastic stability of crystals of different symmetry are presented explicitly.