Revealing the elastic properties and anisotropies of Mg2X(X = Si, Ge and Sn) with different structures from a first-principles calculation. (September 2020)

• Record Type: Journal Article
• Authors: Bao, Longke; Kong, Zhuangzhuang; Qu, Deyi; Duan, Yonghua
• Is Part Of: Materials today communications. Volume 24(2020)
• Publication Date: 2020-09
• Subjects: First-principles calculations -- Mg2X -- Elastic anisotropy -- Sound velocity; Materials science -- Periodicals; 620.11
• DOI: 10.1016/j.mtcomm.2020.101337
• Languages: English
• ISSNs: 2352-4928

Abstract

Abstract: The elastic constants and modulus, elastic anisotropy, Debye temperature, and sound velocity properties of hP 6- and cF 24-Mg2 X (X = Si, Ge, and Sn) compounds were investigated by first-principles calculations, and a comparison with cF 12-Mg2 X was performed. By employing the stress-strain method and Voigt-Reuss-Hill approximation, we calculated the elastic properties of single and polycrystalline crystals, respectively. The calculated Poisson's ratio v, G H / B H and Cauchy pressure P Cauchy values indicate that cF 12-Mg2 X is brittle, while hP 6- and cF 24-Mg2 X are ductile. The elastic anisotropy of Mg2 X (X = Si, Ge and Sn) is estimated by several elastic anisotropy indices, three-dimensional surface constructions and projections of Young's, shear and bulk modulus. The elastic anisotropy of Mg2 X (X = Si, Ge and Sn) is in a sequence of cF24 > hP6 > cF12 . Finally, Debye temperature and the directional sound velocity were obtained from the elastic constant and the modulus conversion, respectively.