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The elastic properties of hexagonal auxetics under pressure
Author(s) -
Goldstein Robert V.,
Gorodtsov Valentin A.,
Lisovenko Dmitry S.
Publication year - 2016
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201600054
Subject(s) - auxetics , materials science , poisson's ratio , hexagonal crystal system , modulus , silicon carbide , bulk modulus , elastic modulus , composite material , condensed matter physics , poisson distribution , crystallography , mathematics , physics , chemistry , statistics
Elastic properties of the hexagonal crystals under pressure were analyzed. Seven crystals with negative Poisson's ratio (auxetics) were revealed at zero pressure. These are crystals of MoS 2 , Zn, Be, BeCu (alloy with 2.4 at.% Cu), TiB 2 , C 7 H 12 , and MnAs. Analytical expressions of extreme values of Poisson's ratio and Young's modulus were obtained. For these materials, the variability of Poisson's ratio and Young's modulus was analyzed at pressure change. It was shown that all seven hexagonal auxetics may become completely auxetic under certain pressure values. The variability of the elastic properties of graphite and SiC, being non‐auxetics at zero pressure, was considered. These crystals become partially auxetic at negative pressure (−15 GPa for graphite and −56 GPa for silicon carbide) and completely auxetic at −114 and −122 GPa, respectively. The surface of auxeticity ν ( θ , ψ ; p ) = 0 for hexagonal auxetic MoS 2 .