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Theoretical Study on the Mechanism of Anisotropic Thermal Properties of Ti 2 AlC and Cr 2 AlC
Author(s) -
Wang Jiemin,
Wang Jingyang,
Li Aijun,
Li Jingjing,
Zhou Yanchun
Publication year - 2014
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.12814
Subject(s) - thermal expansion , anisotropy , isotropy , materials science , thermal , anharmonicity , bulk modulus , elastic modulus , composite material , thermodynamics , condensed matter physics , physics , quantum mechanics
Temperature dependences of thermal and elastic properties, such as the Grüneisen parameters, thermal expansion, bulk modulus, and heat capacity of Ti 2 AlC and Cr 2 AlC , are studied by combining first‐principles method and lattice dynamic calculation based on the quasi‐harmonic model. Experimental thermal expansion coefficient is also measured for comparison. Thermal expansion coefficients of Ti 2 AlC and Cr 2 AlC show different trends: Ti 2 AlC exhibits anisotropic thermal expansion while Cr 2 AlC shows generally isotropic character. The mechanism is explored by investigating the isotropy or anisotropy of Grüneisen parameters (phonon anharmonicity and thermal pressure) and elastic stiffness (response to thermal pressure) of Ti 2 AlC and Cr 2 AlC . In addition, the calculated bulk modulus of Cr 2 AlC is higher at ambient temperature but decreases faster than the value of Ti 2 AlC as temperature increasing.