First-principles study on the elastic anisotropy and thermal properties of Mg–Y compounds. (December 2022)

• Record Type: Journal Article
• Authors: Zhou, Yunxuan; Lin, Yang; Wang, Hailian; Dong, Quan; Tan, Jun
• Is Part Of: Journal of physics and chemistry of solids. Volume 171(2022)
• Publication Date: 2022-12
• Subjects: Magnesium alloys -- Elastic anisotropy -- Mechanical properties -- Thermal properties -- First-principles calculations; Solids -- Periodicals; Solides -- Périodiques; Solids; Periodicals; 530.41
• DOI: 10.1016/j.jpcs.2022.111034
• Languages: English
• ISSNs: 0022-3697

Abstract

Abstract: Magnesium (Mg) alloys are widely used in automobile, rail transit, and other fields; however their heat resistance and deformation ability should be improved. In the present work, the structural characteristics, dynamic stability, mechanical anisotropic, electronic structure, and thermal properties of Mg-Yttrium (Y) binary compounds are systematically explored using the first-principles calculations combined with the quasi-harmonic approximation. The current calculated first-principles results reveal that MgY, Mg2 Y, and Mg24 Y5 are confirmed the dynamically and thermodynamically stable phases at 0 K by the phonon dispersions with no imaginary frequency and formation enthalpy convex hull graph. The calculated mechanical properties of Mg–Y compounds are gradually increased with the increase of Y content, and MgY has the largest elastic moduli, including bulk, shear, and Young's modulus, as the values with 43.82, 26.7, and 66.63 GPa, respectively. The elastic anisotropies of the Mg–Y system are illustrated by elastic anisotropy indexes and three-dimensional surface constructions, and these results show that the sequence of elastic anisotropy are MgY > Mg2 Y > Mg24 Y5 . Additionally, the MgY phase exhibits superior heat resistance compared to the Mg2 Y and Mg24 Y5 phases, which is beneficial to enhance the heat resistance of Mg alloys. Highlights: Mg–Y compounds are confirmed the dynamically and thermodynamically stable phases. The MgY phase has better heat resistance compared to Mg2 Y and Mg24 Y5 phases. The sequence of elastic anisotropy of Mg–Y system are MgY > Mg2 Y > Mg24 Y5 .