Dong CHEN
,
Jingdong CHEN
,
Yinglu ZHAO
,
Benhai YU
,
Chunlei WANG
,
Deheng SHI
金属学报(英文版)
doi:10.1016/S1006-7191(08)60082-4
The equilibrium lattice parameter, relative volume V/V0, elastic constants Cij, and bulk modulus of titanium nitride are successfully obtained using the ab~initio plane-wave pseudopotential (PW-PP) method within the framework of density functional theory. The quasi-harmonic Debye model, using a set of total energy vs molar volume obtained with the PW-PP method, is applied to the study of the elastic properties and vibrational effects. We analyze the relationship between the bulk modulus and temperature up to 2000 K and obtain the relationship between bulk modulus B and pressure at different temperatures. It is found that the bulk modulus B increases monotonously with increasing pressure and decreases with increasing temperature. Moreover, the Debye temperature is determined from the non-equilibrium Gibbs functions.
关键词:
Elastic constants
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Chunlei WANG
,
Qiuju SUN
,
Xuanyu SONG
,
Benhai YU
金属学报(英文版)
doi:10.1016/S1006-7191(08)60100-3
The elastic and physical characteristics of ReB2 crystal have been predicted through a method of density functional theory within the generalized gradient approximation (GGA). Five independent elastic constants are C11=662 GPa, C12=150 GPa, C13=146 GPa, C33=1090 GPa and C44=263 GPa. The bulk modulus (B), shear modulus (G), Young's modulus (E), Poisson's ratio (γ) and the ratio of linear compressibility coefficient along the a- and c-axis crystal direction (Ka/Kc) are 356 GPa, 305 GPa, 711 GPa, 0.167 and 1.758, respectively. In addition, the dependence of bulk modulus (B) on temperature (T) and pressure (p) as well as the coefficient of thermal expansion (αL) at various temperatures are evaluated and discussed. The coefficient of thermal expansion is consistent with the famous Gruneisen's law when the temperature is less than 1500K. Our results agree well with the other experimental results.
关键词:
Rhenium diboride
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